Background: We focused on the risk factors for poor outcome after curative resection of a colon cancer in UICC stages I and II based on the data of the Germany-wide quality assurance study "colon/rectum cancer (primary tumor)." In some countries, all stage II colon cancer patients are encouraged to participate in a clinical trial. We feel that this approach is too broad.
Methods: Using the data of 15,096 patients operated on from January 1, 2000 to December 31, 2004, the following factors were analyzed with the Cox regression model: age, comorbidities, ASA score, gender, localization of the tumor (left colon vs. right colon), perioperative complications (yes/no), pT stage, grading (G1/G2 vs. G3/G4), L-status (lymph vessels invasion yes/no), and V-status (venous invasion yes/no).
Results: The probability of a local relapse in stages I and II was 1.5 and 4.6%, respectively, or distant metastases 4.7 and 10.2%, respectively. Only pT stage [hazard ratio (HR) for pT1 = 1, pT2 = 1.821, pT3 = 2.735, and pT4 = 5.881], L-status (HR for L1 = 1.393), age (HR per year = 1.021), as well as ASA score IV (HR = 4.536) had significant influence on tumor-free survival.
Conclusions: Despite favorable prognosis and R0 resection, a small percentage of patients will still relapse. The most important risk factor comprising the tumor-free survival is the pT stage followed by L-status and age. These results should be taken into consideration when determining the course for adjuvant chemotherapy, especially if the course includes the recommendation of clinical trial participation for stage II colon cancer patients after an R0 resection.