Morbidities of adjuvant chemotherapy and radiotherapy for resectable rectal cancer - An overview

PURPOSE: Although adjuvant chemoradiotherapy may improve outcomes after surgery for high-risk rectal cancer, its toxicities are not well documented. This is a review of complications associated with adjuvant therapy in randomized, controlled trials. METHODS: A MEDLINE and literature search was performed for randomized, controlled trials of adjuvant therapy for rectal cancer. Modalities of adjuvant therapy evaluated included preoperative radiotherapy, preoperative chemoradiotherapy, postoperative radiotherapy, and postoperative chemoradiotherapy, All documented complications were analyzed, including any effect on pelvic floor function and quality of life. RESULTS: Short-term (acute) complications of preoperative radiotherapy include lethargy, nausea, diarrhea, and skin erythema or desquamation. These acute effects develop to some degree in most patients during treatment but are usually self-limiting. With preoperative radiotherapy the incidence of perineal mound infection increases from 10 to 20 percent. The acute toxicities after postoperative radiotherapy for rectal cancer occur in 4 to 48 percent of cases, and serious toxicities, requiring hospitalization or surgical intervention, occur in 3 to 10 percent of cases. Postoperative radiotherapy is associated with more complications than preoperative radiotherapy. The main problems with postoperative radiotherapy are small-bowel obstruction (5-10 percent), delay in starting radiotherapy caused by delayed wound healing (6 percent) and postoperative fatigue (14 percent), and toxicities precluding completion of adjuvant therapy (49-97 percent). The morbidity and mortality of both preoperative and postoperative radiotherapy are higher in elderly patients and when two-portal rather than three-portal or four-portal radiation technique is used. Meticulous radiation technique is important, and multiple fields of irradiation are mandatory. After combined adjuvant chemotherapy and radiotherapy acute hematologic and gastrointestinal toxic effects are frequent (5-50 percent). Delayed radiation toxicities include radiation enteritis (4 percent), small-bowel obstruction (5 percent), and rectal stricture (5 percent). Pelvic floor function and quality of life have not been well evaluated in randomized, controlled trials. CONCLUSION: Adjuvant therapy for rectal cancer has considerable adverse effects. Adverse effects on bowel and sphincter function and quality of life have not been defined.