Stratification of rectal cancer stage for selection of postoperative chemoradiotherapy: current status

Disease relapse (local, distant) and survival rates (overall [OS], disease-free [DFS]) are dependent on disease stage at time of diagnosis. In rectal cancer pooled analyses of phase III North American trials, OS and DFS were dependent on TN stage (N substage within T stage), NT stage (T substage within N stage), and treatment method. Three risk groups of patients were defined: (1) intermediate T1-2N1, T3N0; (2) moderately high T1-2N2, T3N1, T4N0; and (3) high T3N2, T4N1, T4N2. Patients with a single high-risk factor (T1-2N1, T3N0) were shown to have better OS, DFS, and disease control than patients with both high-risk factors. Although adjuvant chemoradiotherapy (CRT) is indicated for patients with moderately high-risk and high-risk stage of disease, many of these patients are currently treated preoperatively if stage of disease can be defined. If surgery precedes adjuvant treatment, however, postoperative CRT is certainly indicated for these risk groups. For patients with intermediate-risk stage of disease (T1-2N1, T3N0), use of trimodality treatment (surgery plus radiotherapy and chemotherapy) in all patients may be excessive. The challenge is in determining which patients can be spared adjuvant CRT and whether it is worth the exercise.