Carcinoma broncogénico no anaplásico de células pequeñas. El nuevo estadio I

Abstract

To validate updated guidelines for stage I classification of patients with differentiated small-cell bronchogenic carcinoma. Seven hundred seventeen tumors of differentiated small-cell bronchogenic carcinoma were resected in our hospital and given a TNM classification of stage I based on guidelines recently issued by the Spanish Society of Pneumology and Chest Surgery (SEPAR). Survival was calculated using the Kaplan-Meier method and curves were compared with a log-rank test. The Cox proportional hazards model was used to analyze multiple variables. One hundred forty-two cases were classified as stage IA and 575 as stage IB. Survival was significantly longer for stage IA than for stage IB (p = 0.0021). The prognosis was significantly better for stage IA patients who were asymptomatic (p = 0.0380) or who had tumors < or = 2 cm in diameter (p = 0.0431). In stage IB, histologic grade (p = 0.0104) and tumor diameter (p = 0.0002) significantly affected survival. A noteworthy finding was the 82% survival at five years in a group of 66 patients with a maximum tumor diameter of 3 cm classified as T2N0M0 due to invasion of the visceral pleura or to proximal involvement of a lobar bronchus at a site > 2 cm from the carina; that survival rate was not significantly different from survival for stage IA (p = 0.1573). Multivariate analysis showed that tumor diameter (p = 0.0272) was of prognostic importance in stage IA, while tumor diameter (p = 0.0005) and histologic grade (p = 0.0092) were relevant in stage IB. The new staging guidelines for differentiated small-cell bronchogenic carcinoma are nearer to prognostic reality given that survival for stage IA patients is significantly longer than for stage IB patients. However, the method continues to have shortcomings in that it fails to achieve one of its main objectives, namely prognostic homogeneity for each subgroup, as indicated by problems related to variables of tumor extension such as diameter, involvement of the visceral pleura or bronchial location, apart from other factors that affect survival.