S-PHASE FRACTION CAN PREDICT EVENT-FREE SURVIVAL IN PATIENTS WITH PT2-T3NOMO COLORECTAL-CARCINOMA - IMPLICATIONS FOR ADJUVANT CHEMOTHERAPY

BACKGROUND. Adjuvant chemotherapy for colorectal carcinoma was found t o improve survival of patients with American Joint Committee on Cancer /International Union Against Cancer Stage III disease. The usefulness of chemotherapy in patients with Stage II disease continues to be deba ted, and it is likely that only those patients with a poor prognosis s hould receive adjuvant chemotherapy. Biologic prognostic factors may a llow further insight into the optimal treatment strategy for patients with Stage II or earlier disease. In this study the prognostic role of S-phase fraction (SPF) determined by flow cytometry was assessed in p atients with Stage I-II colorectal carcinoma. METHODS. Specimens of su rgically resected colorectal carcinoma were examined for SPF by flow c ytometric DNA analysis. Consecutive patients referred to the study ins titution were considered eligible for this study. The main inclusion c riteria were a Stage I-II tumor together with sufficient tumor materia l and adequate follow-up information. For each stage of disease, SPF d ata were associated with the recurrence rate and the disease free surv ival (DFS). RESULTS. Analysis was performed on 167 patients (65 with S tage I disease and 102 with Stage II disease). Among Stage I patients, SPF was high in 20 patients and low in 45 patients. In Stage II patie nts, there were 36 patients with low SPF and 66 patients with high SPF . In both stages, the recurrence rate and DFS were significantly worse for the subgroups of patients with high SPF. CONCLUSIONS, SPF has rev ealed prognostic differences among patients with surgically resected S tage I-II colorectal carcinoma. These data should be considered for pl anning future trials in the adjuvant setting because patients with hig h SPF may benefit from adjuvant chemotherapy. (C) 1998 American Cancer Society.