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DOI: 10.1055/s-0043-1768051
Multiple Primary Malignancies: A Clinicopathological Profile of Patients at a Tertiary Center of North India—A Retrospective Hospital-Based Observational Study
- Abstract
- Background
- Material and Methods
- Results
- Discussion
- Limitations
- Conclusion
- Ethics Approval and Consent to Participate
- References
Abstract
Introduction The incidence, prevalence, as well as survival of cancer patients, is increasing day by day due to the use of screening and improved diagnostic modalities. Simultaneously, the development of multiple primary malignancies (MPMs) in cancer survivors is not uncommon in recent years, because of an improved understanding of biology and effective management of cancer in the form of local (i.e., surgery/radiotherapy) and systemic (chemotherapy/targeted therapy) treatment, leading to improved survival and subsequent development of more malignancies. The study was conducted to describe the clinicopathological profile of patients diagnosed with MPMs.
Objective To study the clinicopathological profile of MPMs and to look for treatment patterns of these patients.
Materials and Methods This was a retrospective hospital-based observational study. Medical records of 73 patients with MPMs, who were registered in the department of medical and surgical oncology between January 2016 and December 2018, were enrolled in the study. The statistical analysis was done by using IBM SPSS Statistics for Windows from IBM Corp. Categorical data were expressed in the form of frequencies and percentages.
Results Out of the total 73 patients, 2 patients were diagnosed to have triple malignancies and were excluded from the study for discussion purposes. Among 71 patients with double malignancies, 19 patients had synchronous and 52 had metachronous malignancies with synchronous to metachronous ratio of 1:2.73. The study included 39 men and 32 women with a male to female ratio of 1.21:1. Gastrointestinal system was the most common system involved in first primary as well as in second primary malignancy. Squamous cell carcinoma and adenocarcinoma equally were the most common histologies seen in primary, whereas adenocarcinoma was the most common histology seen in second primary malignancy.
Conclusions The phenomenon of MPMs is not an uncommon presentation due to longer survival and side effects of treatment (radiotherapy/chemotherapy). It should always be kept in consideration in any cancer survivor during surveillance in order to detect it and treat at the earliest.
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Background
Multiple primary malignancies (MPMs) in cancer patients are not very rare because of prolonged survival due to advances made in the treatment of cancer patients. The probability of recurrence or a secondary from the initial malignancy may delay treatment and impact the overall prognosis and survival, making the diagnosis of MPMs complicated. The most common presentation of MPMs is double malignancies.[1] [2] MPMs were first described by Billroth[3] in 1889 and reported in a detailed study by Warren and Gates[4] in 1932. The criteria for diagnoses of MPM, as proposed by Warren and Gates, include: (1) histological confirmation of malignancy in both the index and second primary tumors; (2) there should be at least 2 cm of normal mucosa between the tumors; if the tumors are in the same location, then they should be separated in time by at least 5 years; (3) probability of one being the metastasis of the other must be excluded.
Double primary malignancies could be divided into two categories, depending upon the interval between tumor diagnoses. Synchronous malignancies are defined where second tumor develops simultaneously or within 6 months after the diagnosis of first malignancy, whereas in metachronous malignancies, second tumor develops after 6 months or more after the diagnosis of the first malignancy.[5]
The aim of our study was to assess the clinical and pathological profile of patients diagnosed with MPMs in our region.
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Material and Methods
This was a retrospective hospital-based observational study. Medical records of 73 patients with MPMs who were registered in the department of medical and surgical oncology between January 2016 to December 2018 were enrolled in the study. The patient's details were entered in a set proforma, which include age, sex, family history, smoking and drinking history, histology of synchronous and metachronous lesions, and treatment received.
Inclusion Criteria
Patients with two or more lesions at different sites with different histology or those with two lesions at different sites with similar histology but with different immunohistochemistry markers were included in the study. The tumors were divided into synchronous and metachronous lesions depending upon the time interval between the occurrence of two lesions. Synchronous tumors developed simultaneously or within 6 months of each other, whereas metachronous lesion occurred more than 6 months apart from each other.
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Exclusion Criteria
Patients with malignancy at different sites but with same immunohistochemistry or disease at same site within 5 years of first malignancy were excluded from the study.
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Sample Size
Sample size was calculated by using the Cochran's formula n = (1.96)[2] p(1-P)/d 2, p = 0.73%, d = 0.10%, and thus, the calculated sample size is 76. Case records of three patients were incomplete and were excluded from the study, so the final sample size of our study was 73 patients having 85% power of study.
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Primary Outcome
To study the clinicopathological profile of MPMs.
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Secondary Outcome
To study the treatment patterns of MPM patients.
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Statistical Analysis
The data analysis was done on a computer running Microsoft Windows. The data were initially entered into a Microsoft Excel spreadsheet to be checked for mistakes. The IBM Corp.'s IBM SPSS Statistics for Windows was used for the statistical analysis (released 2020, Version 27.0. Armonk, New York, USA). The frequency and percentage representations of categorical variables were displayed.
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Results
Out of 13,852 newly diagnosed cancer cases, 73 patients were diagnosed to have MPMs comprising of 0.51% of the total cases enrolled during the study. Two patients had triple malignancies, whereas 71 patients had double malignancies. In the two patients with triple malignancy, one had non-Hodgkin's lymphoma and developed metachronous squamous cell carcinoma of esophagus and adenocarcinoma of sigmoid colon. In another patient with index squamous cell carcinoma of skin (thigh), developed two metachronous malignancies, i.e., renal cell carcinoma and adenocarcinoma stomach. For rest of discussion purposes, we will exclude triple malignancies. Of the 71 cases of double malignancy, 39 (54.92%) were men and 32 (45.07%) were women with a male to female ratio of 1.21:1. Median age of our patients was 55 (30–80) with median time to diagnosis of second cancer of 36 months (12–228).
Among the 71 patients with MPMs, 52 patients harbored metachronous double malignancies, whereas 19 patients harbored synchronous double malignancies with metachronous to synchronous malignancy ratio of 2.73:1. The most common systems involved in primary cancer were gastrointestinal system (GI; 22; 30.99%), breast (8; 11.27%), reproductive (8; 11.27%), urinary tract (8; 11.27%), and head and neck (7; 9.86%), whereas in second primary cancer most common systems involved were GI (28; 39.43%), lung (12; 16.9%), reproductive (8; 11.27%), head and neck (8; 11.27%), and breast (4; 5.63%), with esophagus (8; 11.26%), stomach (7; 9.85%), and breast (7; 9.85%) being the most common organs involved in primary cancers, whereas lung (12; 16.90%), colorectal (9; 12.67%), and stomach (8; 11.26%) being the most common organs involved in second primary cancers ([Table 1], [Fig. 1]). Squamous and adenocarcinoma were equally distributed (16 cases each; 22.53%), the most common histologies involved in primary cancers, whereas adenocarcinoma (22; 30.99%) followed by squamous cell carcinoma (18; 25.35%) were as the most common histologies in second primary cancers ([Supplementary Fig. S1], available in the online version). Of the 71 patients with MPMs, 20 (28.17%) were treated with surgery, 14 (19.71%) with surgery + chemotherapy, 10 (14.08%) with chemotherapy + radiotherapy, whereas in second primary malignancy, 15 (21.12%) underwent surgery; 13 (18.30%) chemotherapy + radiotherapy, and 10 (14.08%) patients received surgery + chemotherapy ([Tables 2] and [3], [Supplementary Fig. S2] [available in the online version])


Abbreviation: CI, confidence interval.
Abbreviations: Adeno, adenocarcinoma; ALND, axillary lymph node dissection; BCS, breast conservative surgery; Chemo, chemotherapy; CLL, chronic lymphocytic leukemia; CT-RT, chemoradiation; DLBCL, diffuse large B cell lymphoma; HGS, Ca-high-grade serous carcinoma; IDC, infiltrating duct ca; NACT, neoadjuvant chemotherapy; NHL, non-Hodgkin's lymphoma; OCR, optimal cytoreduction; PSC, papillary serous adenocarcinoma; PTC, papillary thyroid carcinoma; RAIA, radioactive iodine ablation; RT, radiation therapy; SCC, squamous cell ca; Sx., surgery; TAH, total abdominal hysterectomy with salpingo-oopherectomy; TCC, transitional cell carcinoma; TURBT, transurethral resection of bladder tumor; WLE, wide local excion.
Abbreviations: Adeno, adenocarcinoma; ALND, axillary lymph node dissection; BCS, breast conservative surgery; Chemo, chemotherapy; CLL, chronic lymphocytic leukemia; CT-RT, chemoradiation; DLBCL, diffuse large B cell lymphoma; HGS, Ca-high-grade serous carcinoma; IDC, infiltrating duct ca; NACT, neoadjuvant chemotherapy; NHL, non-Hodgkin's lymphoma; OCR, optimal cytoreduction; PSC, papillary serous adenocarcinoma; PTC, papillary thyroid carcinoma; RAIA, radioactive iodine ablation; RT, radiation therapy; SCC, squamous cell ca; Sx., surgery; TAH, total abdominal hysterectomy with salpingo-oopherectomy; TCC, transitional cell carcinoma; TURBT, transurethral resection of bladder tumor; WLE, wide local excion.
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Discussion
Recently, there has been a sharp increase in the prevalence of MPMs, ranging from 0.7 to 11.7% among various populations.[6] This can be due to multitude of reasons including the improved survival of cancer patients due to improved treatment modalities, better diagnostic modalities, and more stringent surveillance of cancer survivors.[7] The prevalence of MPMs in the studied group was 0.51%.
MPMs are a special phenomenon in the tumorigenesis. A number of studies have been conducted worldwide leading to better understanding of this phenomenon. The etiopathogenesis of MPMs can be attributed to genetic events or the common environmental risk factors.[8] Various other mechanisms like aging, an unhealthy lifestyle, cancer treatments, or interactions between any of these factors are also believed to contribute to the development of MPMs.[9] The increased risk of MPMs can be attributed to field carcinogenesis due to exposure to tobacco, smoking, and alcohol consumption.[10] In our study population, 32% patients had smoking history, and none had history of alcohol consumption.
The treatment of primary malignancy by chemotherapy and/or radiotherapy may contribute to increased risk of second malignancy as both ionizing radiation and cytotoxic agents (etoposide, cyclophosphamide, and Adriamycin etc.) can cause DNA damage leading to carcinogenesis. The harmful effects of these treatments as well as of the tumor microenvironment on the patient's immune system may be an important contributing factor allowing future renegade mutant cancer cells from escaping the body's defense mechanisms. Children and young adults may be especially prone to such iatrogenically induced cancers.[11] This was also seen in our patient population, as around 40% of the patients in total and 51.71% patient in metachronous group had received either chemotherapy/radiotherapy or both as treatment for their primary cancers.
In the present study, the incidence of multiple primaries was more common in men as compared with women with a male to female ratio of 1.21:1. Although MPMs can occur at any age, there are several studies that show that incidence is more in older patient population.[12] [13] [14] [15] [16] The median age in our study was 55 years (range 30–80 years). Etiz et al in their study had male to female ratio of 1.19:1 with a median age of 59 years (range 29–80 years),[17] consistent with our study. The interval between index primary and second primary in our study was 12 to 228 months (median 36 months), which is consistent with other studies[9] [18] (comparison between different studies given in [Table 4]).
Study (ref. No) |
Total no. of patients |
No. of patients with multiple primary malignancies |
Synchronous/metachronous |
Male/female |
Median age (metachronous group) |
Common site |
Median interval between index and second primary (mo) |
|||
---|---|---|---|---|---|---|---|---|---|---|
No. |
% |
Index primary |
Second primary |
Index primary |
Second primary |
|||||
Vadgaonkar et al[18] |
16,461 |
44 |
0.26 |
7/37 |
13/31 |
48 |
56 |
Gynecological |
Gynecological |
38 |
Breast |
Gastrointestinal |
|||||||||
Head and neck |
– |
|||||||||
Etiz et al[17] |
9,772 |
122 |
1.2 |
36/86 |
67/55 |
56 |
62 |
Lung |
Lung |
– |
Gastrointestinal |
Gastrointestinal |
|||||||||
Genitourinary |
Genitourinary |
|||||||||
Zhai et al[9] |
15,321 |
167 |
1.09 |
98/69 |
117/50 |
62 |
64 |
Gastrointestinal |
Gastrointestinal |
31.15 |
lung |
lung |
|||||||||
Head and neck |
Head and neck |
|||||||||
Bisht et al[7] |
3,879 |
29 |
0.74 |
8/21 |
10//19 |
54 |
56 |
Breast |
Gastrointestinal |
– |
Head and neck |
Head and neck |
|||||||||
Lung |
Lung |
|||||||||
Irimie et al[8] |
– |
63 |
– |
24/41 |
34/29 |
58.2 y in entire group |
Genital |
Breast |
– |
|
Breast |
Gastrointestinal |
|||||||||
Gastrointestinal |
Lung |
|||||||||
Present study |
13,852 |
71 |
0.51 |
19/52 |
39/32 |
55 y in entire group |
Gastrointestinal |
Gastrointestinal |
36 |
|
Breast |
Lung |
|||||||||
Reproductive |
Reproductive |
The ratio of synchronous to metachronous malignancies varies in different studies.[19] [20] [21] [22] In a study by Aydiner et al,[14] synchronous malignancies constituted 34%, whereas metachronous malignancies constituted 66%, consistent with our study with synchronous and metachronous malignancy of 27 and 73%, respectively. The most common system involved in first primary as well as second primary malignancy in our study was GI (30.99 and 39.44%) with lung being the most common second primary malignancy after GI (16.9%). In a retrospective study, Zhai et al[9] found that the most common pairs were digestive–digestive (25.75%) followed by digestive–lung pairs (19.16%), which coincides with our findings. In another study conducted by Etiz et al, the most common second primary malignancies were GI (22%) and lung (19%), similar to present study.[17] There is high prevalence of GI malignancies in this region of country, which is presumed due to geographic, dietary, and cultural reasons. In a study from the region by Khan et al,[23] which included 22,180 patients, cancer of esophagus, stomach, and colon were second, third, and sixth most common causes of cancer incidence. This could explain the reason for GI tract being the most common site in both synchronous and metachronous groups.
The possibility of existence of MPMs must always be considered during pretreatment evaluation. There is some evidence that screening will improve outcomes among patients who may develop second malignancies, although the data are limited. The optimal screening modalities and strategies to reduce mortality from second malignancies remain to be defined for most tumor sites.[21] With careful monitoring, second primary tumors can be detected early, and with appropriate intervention might be better managed, without compromising survival.
A sizable prospective study needs to be conducted to better understand the profile and outcome of MPMs in order to better develop the various strategies for screening and early identification of second primary malignancies and to enhance outcomes.
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Limitations
The small sample size and retrospective nature of our study are its primary limitations.
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Conclusion
In conclusion, second primary malignancies are not rare. They can be synchronous or metachronous. Improvements in diagnostic and staging modalities and improved survival after management of primary cancers have increased the detection of second primary malignancies. A strong clinical suspicion and thorough evaluation would be beneficial in the management of these tumors. A regular follow-up in a patient diagnosed and treated for primary malignancy would help not only to detect recurrence but also could detect most of the metachronous second primary malignancies at an early stage.
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Ethics Approval and Consent to Participate
The study was conducted in accordance with the guidelines of the Institutional Ethics Committee (IEC) and approved on January 31, 2022 vide IEC SKIMS No: 2022-34 of the Sheri Kashmir Institute of Medical Sciences (SKIMS), Srinagar. This study was conducted in accordance with the Declaration of Helsinki. As this was a retrospective audit of the hospital records, the full consent of the patients was waived by Institutional Ethics Committee, SKIMS, Srinagar.
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Conflict of Interest
None declared.
Acknowledgments
The authors would like to sincerely thank the Department of Medical Records for their support for data collection.
Consent for Publication
Not Applicable.
Authors' Contributions
A.W.M., S.P., and S.N. designed the study and oversaw the research. A.W.M., S.N., I.A., S.N., and N.A.D. developed the concept and drafted the manuscript. S.N. and N.A.D. prepared the tables and figures. A.W.M., S.N., I.A., N.S., S.P., M.H., and N.A. check data for accuracy, contributed to data preparation and analysis. A.W.M., S.N., I.A., N.S., S.P., M.M.H., and N.A. reviewed the results. A.W.M., S.N., I.A., N.S., S.P., M.M.H., and N.A.D. reviewed all versions of the manuscript. A.W.M., S.N., I.A., N.S., S.P., M.M.H., and N.A.D. finalized the manuscript. All authors reviewed the finalized manuscript. The author(s) read and approved the final manuscript.
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References
- 1 Noh SK, Yoon JY, Ryoo UN. et al. A case report of quadruple cancer in a single patient including the breast, rectum, ovary, and endometrium. J Gynecol Oncol 2008; 19 (04) 265-269
- 2 Lee JS, Moon W, Park SJ. et al. Triple synchronous primary cancers of rectum, thyroid, and uterine cervix detected during the workup for hematochezia. Intern Med 2010; 49 (16) 1745-1747
- 3 Billroth T. General Surgical Pathology and Therapy in 51 Lectures: A Handbook for Students and Physicians. 14th ed. Berlin, Germany: Reimer; 1889: 908
- 4 Warren S. Multiple malignant tumors. A survey of the literatures and statistical study. Am J Cancer 1932; 16: 1358-1414
- 5 Suzuki T, Takahashi H, Yao K. et al. Multiple primary malignancies in the head and neck: a clinical review of 121 patients. Acta Otolaryngol Suppl 2002; (547) 88-92
- 6 Amer MH. Multiple neoplasms, single primaries, and patient survival. Cancer Manag Res 2014; 6: 119-134
- 7 Bisht N, Singh S, Sarin A. et al. The conundrum of dual primary malignancies: four years' experience of a single tertiary care institute in India. Indian J Med Paediatr Oncol 2019; 40: 521-530
- 8 Irimie A, Achimas-Cadariu P, Burz C, Puscas E. Multiple primary malignancies–epidemiological analysis at a single tertiary institution. J Gastrointestin Liver Dis 2010; 19 (01) 69-73
- 9 Zhai C, Cai Y, Lou F. et al. Multiple primary malignant tumors - a clinical analysis of 15,321 patients with malignancies at a single center in China. J Cancer 2018; 9 (16) 2795-2801
- 10 Cheng HY, Chu CH, Chang WH. et al. Clinical analysis of multiple primary malignancies in the digestive system: a hospital-based study. World J Gastroenterol 2005; 11 (27) 4215-4219
- 11 Curtis RE, Freedman DM, Ron E. et al. New Malignancies Among Cancer Survivors: SEER Cancer Registries, 1973-2000. Bethesda, MD: National Cancer Institute; 2006: 9-14
- 12 Hajdu SI, Hajdu EO. Multiple primary malignant tumors. J Am Geriatr Soc 1968; 16 (01) 16-26
- 13 Berge T, Cederqvist L, Schönebeck J. Multiple primary malignant tumours. an autopsy study of a circumscribed population. Acta Pathol Microbiol Scand 1969; 76 (02) 171-183
- 14 Aydiner A, Karadeniz A, Uygun K. et al. Multiple primary neoplasms at a single institution: differences between synchronous and metachronous neoplasms. Am J Clin Oncol 2000; 23 (04) 364-370
- 15 Lee TK, Barringer M, Myers RT, Sterchi JM. Multiple primary carcinomas of the colon and associated extracolonic primary malignant tumors. Ann Surg 1982; 195 (04) 501-507
- 16 Vyas JJ, Deshpande RK, Sharma S, Desai PB. Multiple primary cancers in Indian population: metachronous and synchronous lesions. J Surg Oncol 1983; 23 (04) 239-249
- 17 Etiz D, Metcalfe E, Akcay M. Multiple primary malignant neoplasms: a 10-year experience at a single institution from Turkey. J Cancer Res Ther 2017; 13 (01) 16-20
- 18 Vadgaonkar RA, Nayak SS, Doni S, Digumarti L, Mullapally SK, Digumarti R. Distinct patterns of occurrence, common associations, and survival of patients with second primary malignancies: a 5-year single institute experience with review of literature. Indian J Pathol Microbiol 2021; 64 (04) 725-731
- 19 Jena A, Patnayak R, Lakshmi AY, Manilal B, Reddy MK. Multiple primary cancers: an enigma. South Asian J Cancer 2016; 5 (01) 29-32
- 20 Lv M, Zhang X, Shen Y. et al. Clinical analysis and prognosis of synchronous and metachronous multiple primary malignant tumors. Medicine (Baltimore) 2017; 96 (17) e6799
- 21 Mehdi I, Shah AH, Moona MS. et al. Synchronous and metachronous malignant tumours expect the unexpected. J Pak Med Assoc 2010; 60 (11) 905-909
- 22 Vogel VG. Identifying and screening patients at risk of second cancers. Cancer Epidemiol Biomarkers Prev 2006; 15 (11) 2027-2032
- 23 Khan NA, Ahmad Syed N, Dar NA, Masoodi SR, Lone MM. Changing pattern of common cancers in the last five years in Kashmir, India: a retrospective observational study. Int J Med Paediatr Oncol 2021; 42: 439-443
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Publication History
Article published online:
12 May 2023
© 2023. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)
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References
- 1 Noh SK, Yoon JY, Ryoo UN. et al. A case report of quadruple cancer in a single patient including the breast, rectum, ovary, and endometrium. J Gynecol Oncol 2008; 19 (04) 265-269
- 2 Lee JS, Moon W, Park SJ. et al. Triple synchronous primary cancers of rectum, thyroid, and uterine cervix detected during the workup for hematochezia. Intern Med 2010; 49 (16) 1745-1747
- 3 Billroth T. General Surgical Pathology and Therapy in 51 Lectures: A Handbook for Students and Physicians. 14th ed. Berlin, Germany: Reimer; 1889: 908
- 4 Warren S. Multiple malignant tumors. A survey of the literatures and statistical study. Am J Cancer 1932; 16: 1358-1414
- 5 Suzuki T, Takahashi H, Yao K. et al. Multiple primary malignancies in the head and neck: a clinical review of 121 patients. Acta Otolaryngol Suppl 2002; (547) 88-92
- 6 Amer MH. Multiple neoplasms, single primaries, and patient survival. Cancer Manag Res 2014; 6: 119-134
- 7 Bisht N, Singh S, Sarin A. et al. The conundrum of dual primary malignancies: four years' experience of a single tertiary care institute in India. Indian J Med Paediatr Oncol 2019; 40: 521-530
- 8 Irimie A, Achimas-Cadariu P, Burz C, Puscas E. Multiple primary malignancies–epidemiological analysis at a single tertiary institution. J Gastrointestin Liver Dis 2010; 19 (01) 69-73
- 9 Zhai C, Cai Y, Lou F. et al. Multiple primary malignant tumors - a clinical analysis of 15,321 patients with malignancies at a single center in China. J Cancer 2018; 9 (16) 2795-2801
- 10 Cheng HY, Chu CH, Chang WH. et al. Clinical analysis of multiple primary malignancies in the digestive system: a hospital-based study. World J Gastroenterol 2005; 11 (27) 4215-4219
- 11 Curtis RE, Freedman DM, Ron E. et al. New Malignancies Among Cancer Survivors: SEER Cancer Registries, 1973-2000. Bethesda, MD: National Cancer Institute; 2006: 9-14
- 12 Hajdu SI, Hajdu EO. Multiple primary malignant tumors. J Am Geriatr Soc 1968; 16 (01) 16-26
- 13 Berge T, Cederqvist L, Schönebeck J. Multiple primary malignant tumours. an autopsy study of a circumscribed population. Acta Pathol Microbiol Scand 1969; 76 (02) 171-183
- 14 Aydiner A, Karadeniz A, Uygun K. et al. Multiple primary neoplasms at a single institution: differences between synchronous and metachronous neoplasms. Am J Clin Oncol 2000; 23 (04) 364-370
- 15 Lee TK, Barringer M, Myers RT, Sterchi JM. Multiple primary carcinomas of the colon and associated extracolonic primary malignant tumors. Ann Surg 1982; 195 (04) 501-507
- 16 Vyas JJ, Deshpande RK, Sharma S, Desai PB. Multiple primary cancers in Indian population: metachronous and synchronous lesions. J Surg Oncol 1983; 23 (04) 239-249
- 17 Etiz D, Metcalfe E, Akcay M. Multiple primary malignant neoplasms: a 10-year experience at a single institution from Turkey. J Cancer Res Ther 2017; 13 (01) 16-20
- 18 Vadgaonkar RA, Nayak SS, Doni S, Digumarti L, Mullapally SK, Digumarti R. Distinct patterns of occurrence, common associations, and survival of patients with second primary malignancies: a 5-year single institute experience with review of literature. Indian J Pathol Microbiol 2021; 64 (04) 725-731
- 19 Jena A, Patnayak R, Lakshmi AY, Manilal B, Reddy MK. Multiple primary cancers: an enigma. South Asian J Cancer 2016; 5 (01) 29-32
- 20 Lv M, Zhang X, Shen Y. et al. Clinical analysis and prognosis of synchronous and metachronous multiple primary malignant tumors. Medicine (Baltimore) 2017; 96 (17) e6799
- 21 Mehdi I, Shah AH, Moona MS. et al. Synchronous and metachronous malignant tumours expect the unexpected. J Pak Med Assoc 2010; 60 (11) 905-909
- 22 Vogel VG. Identifying and screening patients at risk of second cancers. Cancer Epidemiol Biomarkers Prev 2006; 15 (11) 2027-2032
- 23 Khan NA, Ahmad Syed N, Dar NA, Masoodi SR, Lone MM. Changing pattern of common cancers in the last five years in Kashmir, India: a retrospective observational study. Int J Med Paediatr Oncol 2021; 42: 439-443

