Patient-reported acute GI symptoms in locally advanced cervical cancer patients correlate with rectal dose

Background and purpose To investigate relationships between patient-reported acute gastro-intestinal symptoms in a locally advanced cervical cancer (LACC) prospective cohort and clinical and dosimetric parameters, while also taking spatial dose into account. Material and methods A total of 103 patients was included, receiving radiotherapy based on a plan-library-based plan-of-the-day protocol, combined either with concurrent chemotherapy or with neo-adjuvant chemotherapy and concomitant hyperthermia. Toxicity endpoints were extracted from questionnaires sent out weekly during treatment and regularly in the acute phase after treatment. Endpoints were defined for symptoms concerning obstipation, diarrhea, fecal leakage, bowel cramps and rectal bleeding. Dose surface maps were constructed for the rectum. Clinical parameters and dosimetric parameters of the bowel bag and rectum were collected for all patients. Results The use of concomitant chemotherapy and an increase in Planning Target Volume (PTV) resulted in a significant increase in reported diarrhea. The dose–volume parameters V5Gy–V25Gy of the rectum were found to be significant, unlike dose–volume parameters of the bowel bag. Additionally, a significantly higher dose to the inferior part of the rectum was found for patients reporting diarrhea. No significance was reached for fecal leakage and bowel cramps. Conclusion The significance of results for patients reporting diarrhea symptoms found for PTV volume indicates a potential benefit for a plan-of-the-day protocol. Additionally, the results suggest that a reduction of inferior rectum dose could decrease patient-reported diarrhea symptoms, while the administration of concomitant chemotherapy appears to lead to radiosensitizing effects that increase these symptoms.