Preoperative TNM evaluation of peripheral clinical stage I small cell lung cancer treated by initial lobectomy with adjuvant chemotherapy.

Surgery with chemotherapy has been the accepted procedure for treating pathological stage I small cell lung cancer. However, there is a question of whether all clinical stage I patients should undergo surgery or not because of discrepancies between clinical and pathological staging. We conducted a retrospective analysis of TNM evaluation and postoperative survival on 10 clinical stage IA (T1N0M0) and 6 stage IB (T2N0M0) patients who had undergone initial lobectomy followed by chemotherapy. Clinical stage IB showed a high incidence of hilar or mediastinal lymph node involvement than stage IA (P=0.04). The accuracy of the T-factor did not differ between both stages. The pathological mean dimension of primary tumors with lymph node metastasis (33.4 mm) was significantly larger than that without metastasis (22.1 mm) (P=0.04). The difference in survival between clinical stage IA (7 of 10) and stage IB (2 of 6) was large but not significant (P=0.07). Four patients in each clinical stage died of cancer relapses. When indicating surgery for clinical stage I small cell lung cancer, it should be taken into account that primary tumors of more than 30 mm in diameter may suggest the possibility of stages more advanced than pathological stage II because of a high incidence of lymph node metastasis.