What proportion of lung cancers can be operated by segmentectomy? A computed-tomography-based simulation

To estimate the probability that a lung cancer arising in a segment has safety anatomical margin for segmentectomy by using a computed-tomography (CT)-based simulation technique.

We measured the volume of each segment by dividing a three-dimensional lung model into a segment model. We also measured the volume of particular portions of each segment that were located away from the intersegmental plane by a predefined distance according to a virtual tumor size of 1, 2, or 3 cm. The probability that a lung cancer arising in the segment has safety anatomical margin for segmentectomy (chance to accept segmentectomy) was expressed as the ratio of this particular portion to the entire segment.

There was significant variability in segment size (smallest, the right medial-basal; largest, the left apicoposterior segment). The chance to accept segmentectomy depended on the segment size and the virtual tumor size; however, irrespective of segment size, there was only a small chance to accept segmentectomy in the bilateral lateral-basal and left anterior segments. Overall, the chance to accept segmentectomy for virtual tumors of 1, 2, and 3 cm in diameter was 33%, 24%, and 18%, respectively. Bisegmentectomy provided 49% chance in resecting virtual tumors that were 2 cm in diameter.

The chance to accept segmentectomy differed greatly in individual segments; it was minimal if a segment was small or located between neighboring segments. Bisegmentectomy can increase the chance to accept segmentectomy. In addition to these results, our method is useful in identifying tumors having eligibility for segmentectomy.