Does the histologic predominance of pathological stage IA lung adenocarcinoma influence the extent of resection?

Abstract

We studied whether histologic subtype according to the new IASLC/ATS/ERS adenocarcinoma classification influences the extent of resection in patients with pathological stage IA lung adenocarcinoma. Data on 288 patients with pathological stage IA lung adenocarcinoma were analyzed retrospectively. Recurrence-free survival (RFS) rates were compared according to clinicopathological characteristics, including predominant histologic subtype and extent of resection. Median follow-up was 38.9months. Lobectomy was performed in 146 patients, and sublobar resection in 142 patients. When recurrence was compared among the low-grade group (adenocarcinoma in situ, AIS; minimally invasive adenocarcinoma, MIA), intermediate-grade group (lepidic, acinar, and papillary) and high-grade group (solid and micropapillary), the RFS rate decreased as the grade increased (p=0.037). There was no recurrence in the low-grade or lepidic predominant groups. The recurrence pattern did not differ according to the type of resection or histological subtype. Even in the intermediate- and high-grade groups, the extent of resection was not significantly related to the RFS rate (p=0.622, p=0.516). The results were unchanged after adjusting for independent risk factors. The concordance rate between clinical and pathological stage IA was good in low (98.6%) and intermediate grade (84.6%) and poor in high grade (41.2%). AIS, MIA, and lepidic predominant may be curable by any type of complete resection. Even in invasive subtypes, lobectomy does not offer a recurrence-free advantage over sublobar resection. However, in the high-grade group, less than half of clinical stage IA was actually pathological stage IA. Physicians should exercise caution whenever sublobar resection is planned.