Keywords
colorectal cancer - global surgery - low-resource setting - surveillance - treatment
Colorectal cancer (CRC) is the third most diagnosed cancer and second leading cause
of cancer-related death worldwide.[1] In 2020, an estimated 1.9 million people were diagnosed with CRC and 940,000 deaths
were attributed to CRC.[2] The global incidence of CRC is predicted to increase to approximately 3.2 million
cases by 2040.[2] While the incidence of CRC is on average sixfold higher in high-income countries
compared with very low-income countries, there have been distinct shifts over the
past decade in the incidence and mortality of CRC across the globe that correlate
with measures of development, including human-development index (HDI) and socio-demographic
index levels.[1]
[3] The incidence and mortality of CRC are rising in low- and medium-HDI countries (Eastern
Europe, Asia, South America), while the incidence and mortality are stabilizing or
decreasing in countries with the highest HDI (United States, Australia, New Zealand,
Western Europe).[3]
The global rise of CRC incidence is multifactorial. Rapid increases in wealth and
economic development in low- and middle-income countries have led to increased exposure
to CRC risk factors including westernization of diet, resulting in consumption of
more red and processed meats, refined sugars, and less intake of fruits, vegetables,
and fiber.[4] Smoking, alcohol use, sedentary lifestyle, and obesity are also thought to contribute.
Increased mortality in low- and middle-income countries may be associated with limited
access to CRC screening resulting in delayed diagnosis, lack of access to adjunct
therapies such as chemotherapy and radiation, as well as health and cultural beliefs.
Meanwhile, the declining mortality in high-income countries can be in part attributed
to more developed health care systems that provide widespread screening programs and
deliver best practices in CRC treatment.
These global trends point toward a widening disparity gap in low- and middle-income
countries that are undergoing economic and societal development, but still do not
possess the infrastructure for effective widespread screening and best practice therapy
for CRC. The rapid rise in CRC cases represents a critical public health issue. In
this article, we will review barriers to care, screening and treatment approaches,
and ongoing developments in CRC care in low-resource settings.
Societal Implications and Barriers to Care
Societal Implications and Barriers to Care
Barriers to evidence-based screening and treatment contribute to poor outcomes of
CRC seen in low- and middle-income countries. Identifying these barriers and developing
strategies to address them can lead to implementation of more widely adopted screening
and treatment programs. These barriers are context and culture specific, and not all
resource-restricted health systems will face the same challenges. Efforts to tailor
CRC screening and treatment programs will depend on a variety of context-specific
factors such as socio-demographics, religious and cultural norms, and health care
infrastructure. A qualitative analysis conducted on a low-income, urban community
in Mexico City identified barriers at multiple levels to implementation of a non-invasive
CRC screening program[5]; at a societal level, they identified poverty, health literacy, and beliefs around
health, cancer, medicine, and gender as major barriers. For example, participants
often shared the view that cancer was a “death sentence.”[5] At a health care system level, lack of CRC awareness among health care providers,
lack of infrastructure, community perceptions around the quality of available health
care, poor doctor–patient communication, and previous experiences of mistreatment
and abuse in health care were found to be major challenges. Finally, at the individual
level, the authors found a lack of CRC awareness, fear of participating in screening,
and distrust in health care providers; and concluded that implementation of CRC screening
in this population would be facilitated by enhanced education of health care personnel
and community members on CRC and its screening options, free screening, as well as
culturally-appropriate, non-fear-based screening messages tailored to lay beliefs.[5]
A study investigating clinician perspectives on using evidence-based CRC treatment
guidelines conducted in Ukraine, where CRC incidence is rising and mortality rates
remain high, demonstrated lack of English proficiency and financial constraints as
significant barriers to using the most updated CRC treatment guidelines among Ukrainian
surgeons.[6] The authors proposed that open-access literature and foreign language translation
should be made available via international societies to low- and middle-income countries.[6]
Populations underserved in CRC care also exist within rural settings in the United
States. Disparities in CRC screening were identified in a population-based study that
compared breast and CRC screening among women living in rural versus urban areas in
the United States.[7] Women in rural and urban communities were equally adherent to breast cancer screening,
however, women living in rural areas were significantly less likely to be adherent
to CRC screening (82 vs. 78%, p = 0.01).[7] Women living in rural areas were found to have lower income and level of education,
higher rate of smoking, and less frequent use of health care than women residing in
urban areas. They also identified more fatalistic beliefs around cancer among the
rural population and skepticism around the use of screening. The authors hypothesized
that the disparities in CRC screening among rural women are partially due to slower
diffusion of medical advances, and that public health interventions such as motivational
messaging around CRC screening and distribution of free non-invasive CRC screening
methods may help with adherence in rural populations.[7]
A systematic review addressing CRC screening barriers in rural U.S. populations identified
multiple factors including high cost, lack of a prevention attitude toward cancer,
fear of finding cancer, embarrassment and perceived lack of privacy, distance to screening
facility, and shortage of specialist as rural-specific barriers to CRC screening.[8] Additionally, gender specific barriers including the belief that CRC mainly affects
men, and race/ethnicity specific barriers including poor provider communication, language
barriers, and immigrant status, were found to contribute to lower rates of CRC screening
in rural settings.[8] Family history of CRC, physician recommendation for screening, and health insurance
were positively associated with CRC screening compliance.[8]
Underserved populations face barriers to CRC care at the policy, health system, provider,
and individual levels.[9] These barriers must be addressed within the context of the resources and attitudes
inherent to each specific setting; an urban location such as Mexico city has different
needs than a rural area in the United States. Poor awareness and communication surrounding
CRC, however, were repeatedly identified as barriers regardless of location, and health
care professionals should strive to provide culturally appropriate education to their
patients about CRC screening and treatment.
Screening and Surveillance Approaches
Screening and Surveillance Approaches
CRC screening tests allow for prevention and early detection of CRC and have been
associated with improved survival, which is directly related to cancer stage at diagnosis.[10] However, due to limited access to screening modalities including colonoscopy, outcomes
in low-resource settings are typically poor, and many patients present emergently
with advanced, late-stage disease. Multiple complexities arise when CRC screening
is considered from a global perspective. Due to the wide variability of health care
environments, there is no “one size fits all” screening program. Moreover, the multiple
testing options for CRC screening, including colonoscopy, sigmoidoscopy, capsule endoscopy
(CE), CT colonography, guaiac-based fecal occult blood tests (gFOBT), fecal immunochemical
testing (FIT), and stool DNA test (i.e., Cologuard), all differ in their cost, accessibility,
and acceptability. Thus, to ensure equitable screening and adequate participation,
the specific health care context must be considered. Even when screening programs
are in place, inequalities in participation associated with socioeconomic status,
education, age, gender, and ethnicity are frequently present.
There are two main CRC screening programs currently in place in multiple countries[11]:
-
Population-based screening: these programs target the entire population based on age. Invitations to screen
are issued from the government or public sector. Typically, a primary screening modality
is followed by secondary testing if positive. There are explicitly defined policies
and systems in place to monitor follow-up of testing, outcomes, and quality control.
-
Opportunistic screening:
-
Structured opportunistic screening: typically supported by official policy with an aim of achieving widespread coverage
of a target population. Screening depends on the individual or health care professional.
-
Ad hoc opportunistic screening: this type of screening depends on the individual or health care professional without
an organized screening program in place.
According to a recent review by Young et al,[11] in 1999 there were only three established screening programs in place across the
world: one population-based organized screening program (Japan) and two structured
opportunistic screening programs (Germany and United States). Since 1999, there has
been a rapid implementation and uptake of CRC screening globally. As of 2018, 29 population-based
organized screening programs (19 European countries, Canada, Uruguay, Israel, United
Arab Emirates, East and Southeast Asia, Australia, and New Zealand) and nine structured
opportunistic screening programs (four European countries, United States, Colombia,
Iran, Japan, and Malaysia) have been implemented.
Population-based screening may eliminate the barriers to access seen with opportunistic
screening, however, this is not universally the case, emphasizing that multifactorial
health care and cultural milieus typically require a more personalized approach. It
is unlikely that asymptomatic population-based CRC screening will be feasible in many
low- and middle-income countries in the near future, thus other paradigms must be
explored in these settings. For example, the role of symptomatic-based surveillance
models is being explored in Nigeria, where a recent multicenter prospective trial
investigated a screening tool to predict increased risk of CRC in patients with rectal
bleeding.[12] Risk stratification is particularly important in resource-limited regions where
the incidence of CRC remains low but mortality is high, as in sub-Saharan Africa.[12] We discuss future directions and technological developments to facilitate risk stratification
and screening in the global context at the end of this articles.
While there are no universal guidelines for CRC screening given the challenges previously
discussed, the American Society of Clinical Oncology (ASCO) put forth resource-stratified
guidelines for CRC screening in 2019. These guidelines are targeted toward individuals
in resource-limited settings where CRC incidence is high, so cannot be widely applied,
however, they provide a concrete framework to guide screening within this sub-population.
The following recommendations have been adapted from the ASCO guidelines[13]:
Screening should take place from the age 50 to 75 years in asymptomatic, average-risk
populations in high-incidence areas:
-
Basic setting: gFOBT or FIT every 1 to 2 years if resources are available.
-
Limited setting: gFOBT or FIT annually, or flexible sigmoidoscopy every 5 years, or
flexible sigmoidoscopy every 10 years plus FIT every year.
-
Enhanced setting: gFOBT or FIT annually, or flexible sigmoidoscopy every 5 years,
or flexible sigmoidoscopy every 10 years plus FIT every year, or colonoscopy every
10 years.
-
Maximal setting: gFOBT or FIT annually, or flexible sigmoidoscopy every 5 years, or
flexible sigmoidoscopy every 10 years plus FIT every year, or colonoscopy every 10
years.
Reflex testing should typically be performed if patients have a positive result from
CRC screening:
-
Basic/limited: Patients should be referred for colonoscopy (preferred) or flexible
sigmoidoscopy if available. If endoscopy is not available, clinicians should refer
patients for double contrast barium enema. If a patient's barium enema is positive,
refer for colonoscopy, if available.
-
Enhanced/maximal: If patients have a positive result from a non-colonoscopy CRC screening
test, colonoscopy should be performed.
Work-up and diagnosis for those with symptoms:
-
Basic/limited: Physical exam with digital rectal examination, double contrast barium
enema, or colonoscopy with biopsy if no contraindications are available. If contraindications
to colonoscopy, then perform flexible sigmoidoscopy and barium enema.
-
Enhanced/maximal: Colonoscopy with biopsy if no contraindications. If contraindications
to colonoscopy, then perform flexible sigmoidoscopy with full visualization of the
colon (barium enema or CT colonography). CT colonography if contraindications to both
endoscopic options or double contrast enhanced barium enema.
Treatment Approaches and Outcomes
Treatment Approaches and Outcomes
Surgical resection remains the pillar of treatment for colon and rectal cancer. With
the rising rate of CRC in low- and middle-income countries, the need for access to
surgeons is critical. Unfortunately, surgical care is often not available in resource-limited
settings. Major challenges to the surgical management of CRC in resource limited settings
include scarcity of surgeons, delays in diagnosis and treatment, limited surgical
capacity of underserved hospitals, poor health literacy, and misconceptions surrounding
surgery. Given these challenges, patients often either do not meet with a surgeon,
or do so once their tumor has progressed to later stages, impacting prognosis and
long-term survival. A study performed in Kenya demonstrated that curative surgery
for patients with CRC in a rural hospital significantly improved survival at 1 and
5 years, identifying prompt surgical evaluation and treatment of CRC in resource-limited
areas as a top health priority.[14]
1. Resource-stratified and evidence-based recommendations on treatment and follow-up
of patients with ASCO.
Summarized below are recommendations by a multinational, multidisciplinary group of
experts using evidence from existing guidelines and clinical experience[15]:
Colon cancer stages I-IIA, non-obstructing:
-
Basic/limited: Open resection following standard oncologic principles (segmental colectomy
with regional en bloc mesenteric lymphadenectomy).
-
Enhanced/maximal: Laparoscopic or minimally invasive surgery (MIS) resection unless
contraindicated (distended bowel, advanced disease, if cannot achieve R0 resection,
or inability to tolerate pneumoperitoneum).
Colon cancer stages IIB-IIC, non-obstructing:
-
Basic/limited: Open resection following standard oncologic principles.
-
○ If not possible, transfer to higher-level facility.
-
○ In emergency, limit to life-saving procedures.
-
Enhanced/maximal: Laparoscopic or MIS resection. If not possible, then open resection.
Colon cancer stages IIB-IIC, obstructing:
Colon cancer diagnoses eligible for adjuvant treatment:
Rectal cancer stage 1 (cT1N0):
Rectal cancer stage 1 (cT2N0):
Rectal cancer stage IIA (cT3N0):
-
Basic/limited: TME or transfer to higher capacity facility. Fecal diversion alone
if obstructing tumor and TME cannot be performed.
-
Enhanced/maximal: TME if R0 resection is expected based on preoperative magnetic resonance
imaging or endorectal ultrasound. If preoperative imaging indicates 1 mm circumferential
resection margin or less, advanced T3 substage or extramural vascular invasion, offers
neoadjuvant therapy.
-
Basic/limited/enhanced/maximal: May offer adjuvant therapy to high-risk stage II and
stage III patients who did not receive neoadjuvant chemotherapy.
2. Minimally invasive options in low-resource settings.
Minimally invasive surgery has led to significant improvements in postoperative recovery
and length of hospital stay. The uptake of MIS techniques, including laparoscopic
and robotic surgery, has been limited in low- and middle-income countries, largely
due to the cost associated with training and equipment.[16] Given the lack of trained personnel and necessary instruments, laparoscopy is not
taught in many postgraduate surgical programs in low-resource countries, and often,
laparoscopic training requires travel by either a visiting surgeon to underserved
communities or by local surgeons to high-resource hospitals.[16] Virtual training via internet-based video platforms such as YouTube and Zoom is
increasingly utilized to conduct remote laparoscopic surgical education. Innovations
in creating inexpensive laparoscopic trainers out of locally available materials have
also shown to be effective in bringing simulation experiences to these settings.[16] Robotic telesurgery, discussed in depth at the end of this chapter, is a cutting-edge
technology that may also play a future role in providing MIS to low-resource settings.
Minimally Invasive Colorectal Surgery in the Global Context
The technical aspects of MIS present a steep learning curve, which is magnified by
the added complexity of CRCs. The dissection required for adequate surgical margins
and lymphadenectomy in both colon and rectal cancer operations is complex and calls
for advanced MIS skills. For example, the pelvic dissection performed during TME necessitates
familiarity with tissue planes as viewed from the laparoscope and experience with
the haptics of MIS instruments for delicate tissue handling. Low colorectal anastomoses
have a higher risk of anastomotic leak, and surgeons performing laparoscopic or robotic
low-anterior resections must be adept at using the MIS-specific staplers to optimize
distal rectal transection and potentially allow for an intracorporeal colorectal anastomosis
that follows optimal surgical technique and principles. Moreover, the instrumentation
is costly and may not be widely available in underserved areas.
We suggest that minimally invasive approaches can play an important role in CRC operations
in low-resource settings where surgeons have received adequate laparoscopic training.
Hand-assisted laparoscopic surgery or laparoscopic colon mobilization followed by
resection and anastomosis through a lower midline or Pfannenstiel incision could potentially
enhance post-operative recovery. This, in turn, could shorten hospital length of stay
and expedite return to work, which ultimately may decrease financial burden to health
care systems and patients.
3. Enhanced recovery after colon and rectal surgery in low-resource settings.
Enhanced recovery after surgery (ERAS) protocols and optimal care pathways have shown
to reduce complications and length of hospital stay compared with conventional recovery
strategies.[17] These pathways contain many recommendations throughout the perioperative course,
including early mobilization and oral intake, goal-directed and early discontinuation
of intravenous fluids, avoidance of urinary catheters and nasogastric tubes, and multimodal
opioid-sparing analgesia, which have shown to be significant predictors of shorter
hospital stay and reduction in the risks of postoperative ileus and surgical site
infection.[18] In 2017, the American Society of Colon and Rectal Surgeons and Society of Gastrointestinal
and Endoscopic Surgeons published clinical practice guidelines for enhanced recovery
after colorectal surgery.[19] These guidelines made multiple recommendations from the preadmission phase through
discharge, many of which are applicable to low-resource settings. In the preoperative
time period, stoma education, marking, and counseling are inexpensive and critical
components of elective colorectal surgery. Stoma teaching has been shown to improve
patient quality of life, reduce length of hospital stay, overall costs, and prevent
hospital readmissions due to dehydration.[19] In resource-limited areas where an ostomy therapist or nurse may not be available,
the operating surgeon can provide ostomy education at the preoperative visit. Additionally,
virtual platforms and online media options may play an increasing role in preoperative
stoma education.
The use of bundles aimed at reducing infectious complications, that include preoperative
mechanical bowel preparation with oral antibiotics and perioperative IV antibiotics
limited to 24 hours postoperative, has been reported to significantly reduce surgical
site infections and postoperative sepsis.[20] Preoperative bowel preparation is relatively cost-effective and accessible with
the benefit of reducing postoperative infectious complications. Intra- and postoperative
components of the guidelines for enhanced recovery after colorectal surgery including
multimodal, opioid-sparing pain control, judicious use of intraoperative crystalloids,
avoidance of abdominal drains and nasogastric tubes, early postoperative mobilization,
early oral feeding, and early discontinuation of intravenous fluids and urinary catheters
should be implemented in underserved settings as much as possible as these interventions
are low-cost and have been shown to improve postoperative recovery.[19]
ERAS protocol implementation in rural hospitals has also been slower than in urban
and suburban regions in the United States. A study by Smucker et al[21] examined pre- and post-ERAS recovery metrics after colon resection at a rural institution.
The authors found that ERAS led to significant reductions in length of hospital stay
and average cost reduction of $3,000 USD per patient. Despite rural-specific barriers
to ERAS protocols such as lack of personnel, poor communication, resistance to change,
patient comorbidities, and socioeconomic disadvantage, ERAS was feasible by overcoming
these barriers, largely through patient and provider education.
4. Improving the quality of CRC resections by rural surgeons.
One of the major factors impacting CRC outcomes, in particular rectal cancer, is volume.
High-volume centers have shown to decrease 30-day mortality and colostomy formation,
increase adherence to treatment guidelines, improve the quality of surgical resection
(higher lymph node yield and lower positive resection margin rate), and improve long-term
overall survival.[22] Surgical volume in rural hospitals is significantly lower. In a recent study examining
Medicare data in critical versus non-critical access hospitals, it was found that
the annual surgical volume per hospital for colectomy was a median of eight cases
versus 92, respectively.[23] This study demonstrated significantly improved in-hospital mortality, complication
rates, and rate of hospital readmission for patients undergoing colectomy in critical
access hospitals. However, these results are heavily confounded by baseline patient
characteristics, with patients undergoing surgery in critical assess hospitals having
significantly less comorbidities and undergoing less emergent operations.[23]
Geographical distance is one of the main barriers that rural providers face. To improve
surgical education for rural general surgeons and to teach CRC-specific surgical principles,
the geographical barrier needs to be overcome. In the era of emerging virtual learning
platforms, virtual-online teaching and video recordings made available on YouTube
should be optimized and encouraged. In addition, virtual and in-person workshops for
teaching lymphadenectomy and total mesorectal excision should be offered to rural
surgeons who have no effective means to refer patients with CRC to hospitals with
specialized CRC care teams. More advanced workshops should also be conducted to teach
principles of MIS colorectal resections and transanal local excision for low-risk
early-stage rectal tumors. Additionally, training of rural pathologists in the assessment
of colorectal specimens is critical to ensure accurate staging so that patients receive
the appropriate postoperative therapies and surveillance.
Context-Appropriate Interventions and Solutions in Development
Context-Appropriate Interventions and Solutions in Development
1. Robotic telesurgery could potentially breach the disparity gap by offering high
quality MIS colorectal resections.
The emerging field of telesurgery, utilizing wireless networks and robotic surgical
systems, allows surgeons to operate on patients in geographically distant locations.
In 2001, the first transcontinental robot-assisted telesurgery was completed using
the ZEUS system (Intuitive Surgical, Sunnyvale, California) by a surgeon in New York
on a patient in Strasbourg, France.[24] A surgeon performed a successful cholecystectomy in 54 minutes and the patient recovered
without complications. Robotic telesurgery has the potential to address some of the
most prescient issues facing global surgery by eliminating geographical barriers to
surgical care and alleviating the global shortage of surgeons in underserved areas.
Telesurgery platforms can also be used as a tool for surgical collaboration and education
between providers at distant locations, facilitating specialized training of surgeons
across the globe. The educational benefits of robotic telesurgery are well demonstrated
in the field of neurosurgery, where a virtual platform has allowed for multiple people
to view a merged surgical field allowing for real-time surgical collaboration and
training of remotely located surgeons.[25] A similar educational model applied to colorectal surgery would greatly benefit
patients undergoing complex resections for CRC and inflammatory bowel disease. Furthermore,
robotic surgery is particularly well suited for three-dimensional visualization of
colorectal anatomy in small operative fields (i.e., pelvis), and enhanced patient
recovery given its minimally invasive approach.
Since the 2001 landmark transcontinental operation, robotic telesurgery remains relatively
limited in its use. The lack of widespread uptake is due to various factors, especially
time latency and delay in transmission between surgeon location and the operating
room. Latency times of 100 milliseconds or less are ideal, and up to 200 milliseconds
are acceptable, while times greater than 200 milliseconds pose technical inaccuracies
and safety hazards.[26] Increased latency times are largely due to network congestion and server overload.[27] For widespread telesurgery to be available, an efficient global network first needs
to be in place and disparities in network availability must be solved. With ongoing
advances in wireless communication technology, including the development of 5G and
fiber-optic networks, the issue of latency time may be overcome. Another limiting
factor is the financial investment required to implement telesurgery programs, which
may be prohibitive for health care systems of less developed countries. Although the
initial implementation cost is high, there is the potential for long-term economic
advantage with telesurgery. For example, if patients with CRC are treated with best-practice
surgery offered by telesurgery, they may suffer less complications from their disease
and health care systems may ultimately incur less burden. Lastly, telesurgery presents
novel billing, insurance, legal, and ethical issues that will need to be addressed
in a global context as its use becomes more common.
Though robotic telesurgery is still in its early phases of development, this technology
poses a platform for a feasible solution to bridge the need-gap that exists amongst
surgical patients in underserved locations worldwide.
2. Use of artificial intelligence for identifying high-risk populations for screening
purposes.
Due to the challenges that low-resource health care settings face in establishing
comprehensive CRC screening programs, elaborating protocols to increase early detection
of CRC remains a critical area for improvement. Employing artificial intelligence
to augment currently available screening modalities may aid in identifying high-risk
populations to streamline and create efficiency in CRC screening. Artificial intelligence
also has the potential to improve the overall quality of CRC screening across multiple
modalities, which would ultimately reduce CRC incidence and mortality not only in
resource-limited areas but for all-comers.
Machine learning, specifically deep learning and neural network processing is being
utilized to aid with image classification in CRC screening. These technologies, known
as computer-aided diagnosis (CAD) systems, seek to enhance both polyp detection and
classification during colonoscopy.[28] The adenoma detection rate (ADR), adenoma miss rate (AMR), and interval CRC development
are important quality metrics of CRC screening. Higher ADR decreases the risk of post-colonoscopy
interval CRC development, which has been shown to be as high as 8.6%.[28] AMR, ranging from 6 to 27%, may be due to inadequate bowel preparation, polyp size,
withdrawal time, and operator experience. Use of automated polyp detection systems
in real-time may significantly increase ADR during colonoscopy, which has been borne
out in studies using CAD systems in conjunction with colonoscopy.[28]
[29] The use of CAD systems may help with diagnostic accuracy and ensure high quality
screening in settings where there may not be an adequate number of experienced endoscopists
to serve a population.
Given the scarcity of endoscopists in many underserved communities, the ability to
perform colonoscopy as a population-based screening strategy may not be attainable
and thus, other high-quality alternatives should be considered. CE is an attractive
option in settings that lack traditional endoscopic resources. However, the accuracy
of polyp detection by CE and subsequent colonoscopy remains uncertain. Additionally,
the traditional manual process of identifying polyps on the images generated from
CE is labor intensive and time consuming and does not address the need for polypectomy.
Deep learning is being used to increase CE polyp matching capabilities and develop
autonomous polyp detection algorithms. A recent prospective study in Denmark including
255 patients undergoing CE and subsequent colonoscopy investigated a matching algorithm
that was able to detect polyps with 97% sensitivity and 93% specificity.[30] Automated CE screening technology could bridge the gap in worldwide screening due
to scarcity of endoscopic equipment and trained practitioners in low-resource settings.
Virtual colonoscopy using CT colonography is another alternative to colonoscopy that
will benefit from artificial intelligence, and machine learning algorithms are being
explored to increase its ability to accurately detect precancerous lesions.[31]
One exciting application of artificial intelligence relevant to global surgery is
its potential use in CRC risk-stratification of the general population. This is well
illustrated in a retrospective study conducted on two national cohorts, one from Israel
and the other from the United Kingdom, that used machine learning to develop and validate
a model to identify patients at increased risk of CRC.[32] The model used individual trends in blood counts, age, and sex on sets of controls
and cases collected 3 to 6 months prior to the diagnosis of CRC. A major strength
of this model is that it is not based on presence of symptoms, which typically present
at later stages of disease, but rather on laboratory value changes that precede symptom
onset. They found their model to be significantly better at detecting CRC than age
alone (basis for current screening guidelines), or iron-deficiency anemia guidelines,
and it was able to identify earlier stage CRCs. When combined with gFOBT, its detection
rate doubled. As the use of electronic medical records becomes more widespread across
the world, using artificial intelligence predictive models in this manner may help
identify at-risk individuals who can then be referred for further work-up. This will
help appropriately allocate resources, such as endoscopic evaluation, to those who
are most likely to benefit from it.
While artificial intelligence technology is still in its early phase for CRC screening,
it has made its way into clinical practice for enhancing detection rates in mammography
and CT scans for lung cancer. Artificial intelligence also has a vast potential to
improve access to and quality of CRC screening among underserved populations, which
would ultimately reduce the significant morbidity and mortality from this disease
worldwide.
Conclusion
The global health inequities present in CRC incidence, mortality, and care exist within
complex, multilayered societal frameworks. The disproportionate burden of CRC, with
rising incidence and mortality in low- and middle-income countries, represents a disparity
that can potentially be reduced through implementing widespread screening and best-practice
treatments. The challenges to screening and surgical care of CRC in resource-limited
settings are diverse, shaped by the cultural nuances and health care infrastructure
of a specific community. Promisingly, there is a great deal of research being done
to identify barriers and develop strategies to address them. Potential solutions in
limited settings, such as utilizing targeted screening programs that identify at risk
individuals to efficiently allocate endoscopic equipment and personnel, need to be
coupled with culturally specific community level interventions that spread knowledge
and debunk misconceptions surrounding CRC. While surgical guidelines for best-practice
treatment ideally should be adopted, the global paucity of surgeons, lack of comprehensive
CRC surgical training, and limited surgical equipment require surgical care to be
tailored to the available resources. Finally, innovative technologies using artificial
intelligence, machine learning, and remote telesurgery may play a role in bridging
the gap in global CRC care in the future, and more research and development in this
field are warranted.
