Sub-solid lung adenocarcinoma in Asian versus Caucasian patients: different biology but similar outcomes

Asian and Caucasian patients with lung cancer have been compared in several database studies, with conflicting findings regarding survival. However, these studies did not include proportion of ground-glass opacity or mutational status in their analyses. Asian patients commonly develop sub-solid lung adenocarcinomas that harbor EGFR mutations, which have a better prognosis. We hypothesized that among patients undergoing surgery for sub-solid lung adenocarcinomas, Asian patients have better survival compared to Caucasian patients.

We identified Asian and Caucasian patients who underwent surgical resection for a sub-solid lung adenocarcinoma from 2002 to 2015 at our institution. Sub-solid was defined as ≥10% ground-glass opacity on preoperative CT scan or ≥10% lepidic component on surgical pathology. Time-to-event multivariable analysis was performed to determine which characteristics were associated with recurrence and survival.

Two hundred twenty-four patients were included with median follow up 48 months. Asian patients were more likely to be never smokers (76.3% vs. 29.0%, P<0.01) and have an EGFR mutation (69.4% vs. 25.6% of those tested, P<0.01), while Caucasian patients were more likely to have a KRAS mutation (23.5% vs. 4.9% of those tested, P<0.01). There was a trend towards Asian patients having a higher proportion of ground-glass opacity (38.8% vs. 30.5%, P=0.11). Time-to-event multivariable analysis showed that higher proportion of ground-glass opacity was significantly associated with better recurrence-free survival (HR 0.76 per 20% increase, P=0.02). However, mutational status and race did not have a significant impact on recurrence-free or overall survival.

Asian and Caucasian patients with sub-solid lung adenocarcinoma have different tumor biology, but recurrence-free and overall survival after surgical resection is similar.