Argon plasma coagulation in chronic radiation proctitis: Postgate et al.

I read the paper “Argon plasma coagulation in chronic radiation proctitis” (Postgate et al.) with interest [1]. As an expert review of the technical issues related to argon beam ablation, it is excellent; however, as a review of how to treat patients with rectal bleeding after radiotherapy, it fails to address a number of salient issues.

First, the authors fail to point out that there are no randomized trials of argon beam ablation in patients with radiation-induced telangiectasia. Indeed, of the eight studies they cite, five are retrospective. With such data it is difficult to be certain as to the true benefit of the intervention especially when there is evidence that radiotherapy-induced rectal telangiectasia may spontaneously improve with time [2].

Secondly, the authors fail to include two other prospective and six other retrospective studies [3] [4] [5] [6] [7] [8] [9] [10] in their analysis. If they had included these studies, it would not have altered their conclusion that most patients with mild to moderate radiation proctopathy are reported to have reduced rectal bleeding after intervention with the argon beamer. However, they would have been able to compute that these published data series together report a serious complication rate of 8 % from the use of the argon beamer in this situation. There are very few other situations in endoscopy where such a high complication rate would be tolerated.

For many years, it has been thought that telangiectasia developing in the gastrointestinal tract after pelvic radiotherapy is due to localized ischemia induced by the radiotherapy. A recent publication challenges that premise [11] but probably the ischemia hypothesis is sound. It seems likely that the worse the ischemia, the more telangiectasia will develop. The more the telangiectasia, the more likely that the patient will bleed.

So I believe that with the current state of knowledge, it is preferable to adopt the diametrically opposite view to Postgate and colleagues. Argon plasma coagulation (APC) in patients with radiotherapy-induced bleeding should be a tool of last resort and should only be attempted by experts. In patients with minor bleeding not affecting quality of life, once endoscopic assessment has confirmed the cause of the bleeding and excluded the presence of other coexisting pathology, endoscopic intervention is not needed. The patient should be reassured and sent on their way. In patients, with significant bleeding, not only does argon beam ablation often fail but in addition, these patients are potentially at the greatest risk of complications, because they have the most ischemic rectums. In a very ischemic rectum, even a shallow ulcer caused by APC may not heal, may cause severe chronic pain, and may induce fibrotic proliferation leading to stricturing and loss of function.

The quality of the published literature is such that it is impossible to be sure whether most of the patients who developed serious complications from APC were those with the heaviest bleeding. However, if it were to be assumed that all the complications did occur in the most symptomatic patients, that is, in those requiring transfusion, that is, those with the most severe ischemia in the rectum, then from the published literature one could compute a serious complication rate of 26 % in those patients. A horribly sobering thought.

”Physician do no harm”. Just because we have a tool, it does not mean we should use it. Many of these unfortunate patients are polysymptomatic with diarrhea, frequency, urgency, and incontinence as well as bleeding. To treat the bleeding with a modality which significantly risks increasing these patients’ morbidity, must be avoided at all cost, especially as APC has no effect on these other often more debilitating symptoms.

So if we are to practice evidence-based medicine, only two treatments have been shown in randomized trials to be beneficial for the treatment of radiotherapy-induced telangiectasia. One is the use of sucralfate enemas. The other is oral metronidazole for 4 weeks [12]. Clearly if patients need treatment, evidence-based therapies should be used as a first line. We know that other treatments such as steroids and 5-aminosalicylic acids (5-ASAs) do not work in this situation. Hyperbaric oxygen probably has the best evidence to support its use as second-line therapy.

I believe that all endoscopic intervention for patients with heavy bleeding after radiotherapy is potentially very hazardous. Even the use of formalin, which the authors suggest as an alternative if APC does not work, is not without worry. There is evidence that formalin used topically in the rectum worsens local ischemia [13]. However, although many of us use formalin, a review of the quality of the outcome data suggests that it is as difficult to reach a reliable conclusion about the benefits and risks of formalin as it is of the argon plasma coagulator [14].

What is the solution if patients have heavy bleeding affecting quality of life? I do not know. It is clear however, that there is an urgent need for a proper, multicenter placebo-controlled randomized trial of the various possible endoscopic interventions. I suspect that endoscopists help very few of these patients. This is really the very last group of patients in whom a “have-a-go” approach should be adopted. If a serious complication arises from endoscopic therapy, patients of this type are condemned to a dire future.

References

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