Evaluation of incidence of intestinal complications during radiation therapy in two supine and prone positions in patients with rectal cancer

Introduction: Radiation therapy is one of the main treatments for rectal cancer. In three-dimensional conformal radiotherapy, exposure of healthy tissue around the tumor is unavoidable. The small intestine is the most important organ at risk of rectal cancer radiotherapy. Intestinal complications are a major factor limiting the dose radiotherapy for rectal cancer. The most common complication of exposure to the small intestine is diarrhea which can lead to stopping patient treatment. In radiation therapy for rectal cancer, there is no standard position and the supine and prone positions, according to doctors from both will be used. In this study, we investigated the incidence and severity of diarrhea as the most common complication of small intestinal in rectal cancer radiotherapy in two supine and prone positions. Materials and Methods: In this study, 10 patients with rectal cancer with an average age of 57 years (range 50-65 years) in two groups with different positions, were followed weekly during treatment. Grade diarrhea was evaluated by a questionnaire based on CTCAE criteria. statistical analysis was performed with the SPSS software. Results: At least until the end of treatment all patients experienced grade 1 diarrhea. In the fourth week of treatment, the incidence and severity of diarrhea in both groups reached the highest levels. The results in this week was as follows: in the prone position, grade I and grade II was 40% and 60% respectively; in the supine position, grade I, grade II and grade III was 40%, 40% and 20% respectively. The mean diarrhea grade that observed at the end of each week in the prone position was lower than in the supine position, but this difference was not significant (p>0.05). Conclusion: Overall, there is no significant difference between the two supine and prone positions, but the use of prone position seems to reduce the severity of diarrhea in patients and can lead to improved quality of life for these patients.