Adjuvant radiochemotherapy--what is the patients benefit?

Local relapse is a major problem after potentially curative rectal cancer surgery. Although the incidence of local recurrences may be reduced by specialized surgical techniques such as total mesorectal excision (TME), local relapse rates of 20% or higher are the surgical reality today. Studies using adjuvant postoperative radiotherapy, chemotherapy, radiochemotherapy or immunotherapy have tried to reduce local relapse rates and distant progression. Postoperative radiochemotherapy has been the recommended standard, after complete resection of Union Internationale Contra la Cancrum (UICC) stages II and III rectal cancers. In view of recent positive results with preoperative radiotherapy of TME without adjuvant therapy, we found it important to review the literature to update the recommendable adjuvant procedure in rectal cancer.

The literature from 1985 to May 1998 was reviewed for studies trying to either confirm or improve adjuvant therapy in rectal cancer. Only randomized controlled trials were analyzed with regard to their effectiveness in reducing the absolute rates of local recurrence and improving survival.

Two trials applying adjuvant radiotherapy were able to demonstrate the reduction of local relapse rates, one trial with marginal significance, both without impact on survival. Four trials involving 1104 patients with rectal cancer stages UICC II-III compared postoperative radiochemotherapy with either surgical controls, adjuvant radiotherapy or conventional radiochemotherapy. In these trials, local relapse rates were significantly reduced by 11-18%, and survival rates significantly improved by 10-14%. Severe acute toxicities occurred in 50-61% of the patients, compromising compatibility, and caused death in 0-1%. Small-bowel obstruction leading to surgery was noted in 2-6% and to death in up to 2% of the patients. Intraoperative radiotherapy (IORT) improved local control and survival after surgery of locally advanced disease/local relapse.

In view of four trials demonstrating a significant benefit of postoperative radiochemotherapy and with regard to recent still-debatable results of preoperative short-term radiotherapy optimal surgery with lowest local relapse rates plus postoperative radiochemotherapy remains the actual recommendable standard for rectal cancer surgery in R0 resected tumors stages UICC II+III.