Figure 1. Distribution of patients in the three study periods according to the extent of resection. Subtotal lobectomy and near-total lobectomy refer to remnant sizes of 2 to 4 g and 1 g or less, respectively. In total lobectomy, no residual tissue is left; enucleation is the localized removal of a circumscribed pathologic lesion. The proportion of extensive resections increased in periods 2 and 3.