In rectal cancer pooled analyses of phase III North American trials, both overall survival (OS) and disease-free survival (DFS) were dependent on TN stage, NT stage, and treatment method. Three risk groups of patients were defined: intermediate (T1-2N1, T3N0), moderately high (T1-2N2, T3N1, T4N0), and high (T3N2, T4N1, T4N2). Patients with a single high-risk factor (T1-2N1, T3N0) have better OS, DFS, and disease control than patients with both high-risk factors. Within TNM stage II rectal cancer, different treatment strategies are indicated for stage IIA (T3N0) versus stage IIB (T4N0) patients based on differential rates of survival and disease relapse. Use of trimodality treatment (surgery plus radiation and chemotherapy; S+RT+CT) for all T3N0 patients may be excessive, as S+CT resulted in 5-year OS of approximately 85% in the second rectal cancer pooled analysis; however 5-year DFS with S+CT was 69% indicating room for improvement. Stage IIB patients are preferably treated with preoperative chemoradiation, but stage IIA patients could appropriately be treated with either preoperative or postoperative chemoradiation.
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