The role of radiological imaging in the patient with gastrointestinal symptoms after pelvic radiotherapy

In recent years there have been sustained improvements in the outcomes from pelvic malignancy, with the introduction of new radiotherapy or combined chemotherapy– radiation treatment schedules [1,2]. Approximately four out of 10 people with cancer will have radiotherapy as part of their treatment. In the UK this includes about 12 000 patients annually who are treated with radiotherapy for pelvic cancer, mainly with curative intent. As screening programmes increase the numbers diagnosed at an earlier stage and treatments have become more effective, more patients are surviving longer. However, radical therapy with the aim of curing the patient of their cancer carries a risk for normal tissues around the tumour. During their 6 week course of radiotherapy, partly because of mucosal damage, 80% of patients will develop gastrointestinal problems—mainly diarrhoea, but also abdominal cramps, tenesmus or faecal incontinence. Nevertheless, almost all patients manage to continue with their radiotherapy. In the acute setting, it is very rare for a patient to be referred for gastrointestinal investigations. Perhaps, this is a pity. Frequent specialist evaluation at this stage might have contributed to a better understanding of why the acute radiation reaction sometimes resolves with no gastrointestinal sequelae, but in other patients evolves into difficult chronic symptoms or serious complications. Although it is clear that late gastrointestinal symptoms are not entirely dose related and depend on a complex interaction of physical, patient-related, treatment and genetic factors, we do not know precisely how often chronic gastrointestinal problems will develop. However, herein lies a problem. Data from our unit suggest that in one-quarter of the patients referred with new gastrointestinal symptoms after radiotherapy, the cause is unrelated to the radiotherapy [3]. So, just because symptoms start after radiotherapy, it does not necessarily follow that they are caused by the radiotherapy. However, we do know that after treatment, 80% will have developed a permanent change in their bowel habit compared to before radiotherapy. Many authors minimise the significance of this change although detailed study of long-term survivors suggests that their altered bowel habit affects quality of life in half of them [4]. The commonest symptoms in these patients which generate referral to gastroenterologists in the UK include diarrhoea, rectal bleeding, bowel frequency, tenesmus and abdominal pain but other problematic issues include urgency, faecal incontinence, weight loss, non-obstructed vomiting, wind, need for nocturnal defecation and steatorrhoea [3]. There are few data about the diagnostic significance of individual symptoms in these patients. Those that do exist suggest that the clinician should be wary about assuming the specific symptoms are due to a specific cause. Small studies have investigated why patients develop chronic diarrhoea after pelvic radiotherapy and have found a wide