RCR3: Modern pelvic chemoradiotherapy techniques continue to affect the small bowel
1The Christie NHS Foundation Trust, Manchester, UK,2Salford Royal NHS Foundation Trust, Manchester, UK,3University of Manchester, Manchester, UK
Diarrhoea is common during pelvic chemoradiotherapy and is multifactorial in origin. Previous studies show a rate of 44-57% bile acid malabsorption (BAM), 26% small intestinal bacterial overgrowth (SIBO) and 15-44% lactose intolerance during the acute toxicity phase. We aimed to determine the rate of these diagnoses in patients receiving newer techniques at our centre.
This study was part of a trial evaluating the use of a gastrointestinal intervention for patients with cervical and bladder cancer receiving pelvic chemoradiotherapy. When patients developed lower gastrointestinal symptoms, tests were performed to detect BAM, SIBO and lactose intolerance.
Ten patients had cervical cancer, 6 received conformal therapy and 4 received Volumetric Modulated Arc Therapy (VMAT). Of the 11 patients with bladder cancer, 10 were male. All received conformal radiotherapy. All patients received weekly chemotherapy. Twenty patients had hydrogen methane breath testing for SIBO and 17 for lactose intolerance. Twenty patients underwent SeHCAT (to detect BAM).
Overall the prevalence of BAM was 65% (13/20). SeHCAT was positive in 90% of the patients with cervical cancer (75% of those who received VMAT) and 40% of the patients with bladder cancer. Of the 13 patients who had BAM the prevalence of mild, moderate and severe BAM were 23%, 31% and 46% respectively. SIBO was diagnosed in 21% (4/19). Of patients with cervical cancer 38% (3/8) had SIBO compared with 9% (1/11) patients with bladder cancer. Lactose intolerance was diagnosed in 29% (5/17) patients. Of the patients with bladder cancer 30% (3/10) had lactose intolerance while 29% (2/7) of the patients with cervical cancer tested positive.
Despite recent advances in radiotherapy treatment, the prevalence of BAM, SIBO and lactose intolerance in this study is similar to that previously described suggesting that new techniques do not reduce the risk of small bowel bystander effects.