There are a number of clinicopathologic variables that predict outcome in rectal cancer. In the era of postoperative chemoradiation treatment, these were more easily identified and were used to help select patients for adjuvant therapy.
Bruce D. Minsky, MD
This article reviews current evidence in support of a watch-and-wait approach to rectal cancer management, and discusses the challenges and limitations of this approach.
As with any legislation, there are both positive and negative aspects. Specific to oncology, one of the greatest impacts of the ACA will be the move to a bundled payment for a treatment of a disease.
Treatment for patients with locally advanced, resectable rectal cancer has clearly evolved, with significant refinements in preoperative assessment, surgical technique, and use of preoperative chemoradiation.
Based on positive results from the Radiation Therapy Oncology Group (RTOG) 85-01 trial, the conventional nonsurgical treatment of esophageal carcinoma is combined-modality therapy. Dose intensification of the RTOG 85-01 regimen, examined in the Intergroup (INT)-0123/RTOG 94-05 trial, did not improve local control or survival. Areas of clinical investigation include the development of combined-modality therapy regimens with newer systemic agents, the use of 18F-fluorodeoxyglucose positron-emission tomography to assist in the development of innovative radiation treatment planning techniques, and the identification of prognostic molecular markers. The addition of surgery following primary combined-modality therapy apparently does not improve survival, but this finding is controversial.
Colon cancer is a major public health problem. The primary treatment is resection. For patients with early-stage disease, surgery results in excellent survival rates. In contrast, patients with locally advanced tumors arising in "anatomically immobile" segments of large bowel have a less satisfactory outcome, in part secondary to compromised surgical clearance. Patterns-of-failure analyses suggest that for tumors that invade adjacent organs, exhibit perforation or fistula, or are subtotally resected, local failure rates exceed 30%. Multiple single-institution retrospective studies have shown improved local control and possibly survival with the addition of external irradiation and/or intraoperative radiation. In contrast, a recent Intergroup trial failed to show any benefit by the addition of adjuvant radiation therapy combined with chemotherapy. Interpretation of this trial's results is handicapped by low patient accrual. With the advent of novel and more effective systemic therapies for metastatic colon cancer, current and future clinical research will address the efficacy of these agents in the adjuvant setting. Adjuvant radiation therapy should be considered in patients with colon cancer at high risk for local failure.
There are two conventional treatments for clinically resectable rectal
cancer. The first is surgery followed by postoperative combinedmodality
therapy if the tumor is T3 and/or N1/2. The second, if the
tumor is ultrasound T3 or clinical T4, is preoperative combined-modality
therapy followed by surgery and postoperative chemotherapy. There
are a number of new chemotherapeutic agents that have been developed
for the treatment of colorectal cancer. Phase I/II trials are examining
the use of new chemotherapeutic agents in combination with pelvic
radiation therapy, most commonly in the preoperative setting. There
is considerable interest in integrating irinotecan (Camptosar) into preoperative
combined-modality therapy regimens for rectal cancer. Based
on these trials, the recommended regimen for patients who receive
irinotecan-based combined-modality therapy is continuous infusion
fluorouracil (5-FU), irinotecan, and pelvic radiation. New trials examining
preoperative combined-modality therapy regimens substituting
capecitabine (Xeloda) for continuous infusion 5-FU are in progress.