The prognostic inhomogeneity in pT3 rectal carcinomas

To obtain data on locoregional recurrence and survival rates in prognostica lly inhomogeneous pT3 rectal carcinomas we analyzed the data on 853 patient s of the Erlangen Registry for Colo-Rectal Carcinomas (ERCRC) and 600 patie nts of the Study Group for Colo-Rectal Carcinoma (SGCRC), stage I-III, trea ted by radical surgery alone. The category pT3 was subdivided according to the histological measurement of the maximal tumor invasion beyond the outer border of the muscularis propria: pT3a (up to 5 mm) and pT3b (more than 5 mm). In the ERCRC locoregional recurrence rates were 10.4% (95% confidence interval 6.0-14.6) for pT3a and 26.3% (20.6-31.6) for pT3b (P <0.0001). The cancer-related 5-year survival rates were 85.4% (80.6-90.5) for pT3a and 5 4.1% (48.5-60.5) for pT3b (P <0.0001). Lymph node negative pT3a and pT2 pat ients showed very similar 5-year survival rates (91.2% vs. 93.6%, respectiv ely) as well as lymph node positive pT3a and pT2 patients (77.8% vs. 82.8%, respectively). In the SGCRC patients similar but statistically marginal di fferences between pT3a and pT3b tumors were observed. An extended pT classi fication (pT1, pT2, pT3a, pT3b, pT4) thus allows an improved prediction of outcome in rectal carcinoma patients. The subdivision of pT3 enables the id entification of stage II patients (pT3a pN0) who might not benefit from adj uvant treatment.