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

PURPOSE: Although adjuvant chemoradiotherapy may improve outcomes after sur gery for high-risk rectal cancer, its toxicities are not well documented. T his is a review of complications associated with adjuvant therapy in random ized, controlled trials. METHODS: A MEDLINE and literature search was perfo rmed for randomized, controlled trials of adjuvant therapy for rectal cance r. Modalities of adjuvant therapy evaluated included preoperative radiother apy, preoperative chemoradiotherapy, postoperative radiotherapy, and postop erative chemoradiotherapy, All documented complications were analyzed, incl uding any effect on pelvic floor function and quality of life. RESULTS: Sho rt-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 se lf-limiting. With preoperative radiotherapy the incidence of perineal mound infection increases from 10 to 20 percent. The acute toxicities after post operative 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 associat ed with more complications than preoperative radiotherapy. The main problem s with postoperative radiotherapy are small-bowel obstruction (5-10 percent ), delay in starting radiotherapy caused by delayed wound healing (6 percen t) and postoperative fatigue (14 percent), and toxicities precluding comple tion of adjuvant therapy (49-97 percent). The morbidity and mortality of bo th preoperative and postoperative radiotherapy are higher in elderly patien ts and when two-portal rather than three-portal or four-portal radiation te chnique is used. Meticulous radiation technique is important, and multiple fields of irradiation are mandatory. After combined adjuvant chemotherapy a nd radiotherapy acute hematologic and gastrointestinal toxic effects are fr equent (5-50 percent). Delayed radiation toxicities include radiation enter itis (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 fo r rectal cancer has considerable adverse effects. Adverse effects on bowel and sphincter function and quality of life have not been defined.