A recent study has demonstrated that among patients with surgically resected stage I NSCLC, those with ADC had a lower risk of death than those with SqCC. However, in patients with stage II and III NSCLC, whether the prognosis varies depending on the histologic subtype remains unclear. 

A total of 2155 consecutive adult patients who underwent complete resection of stage II and III NSCLC between 2008 and 2018 were enrolled. The primary endpoints were freedom from recurrence (FFR) and overall survival (OS). The secondary endpoint was the time to lung cancer or non-lung cancer death.

Of the 2155 patients, 1436 (66.6%) had adenocarcinoma (ADC) and 719 (33.4%) had squamous cell carcinoma (SqCC). Patients with SqCC had better FFR than those with ADC (stage II, p < 0.001; stage III, p < 0.001). Although patients with ADC showed a slightly better OS until 5 years than those with SqCC, the difference was insignificant (stage II, p = 0.292; stage III, p = 0.196). Patients with SqCC had higher rates of non-lung cancer death than patients with ADC (stage II, p < 0.001; stage III, p = 0.039). The time from lung cancer recurrence to death was shorter in patients with SqCC than in those with ADC (stage II, median 13 vs. 37 months, p < 0.001; stage III, median 11 vs. 26 months, p < 0.001).

In stage II and III NSCLC, ADC had a higher risk of recurrence than SqCC, with no difference in OS. These results were related to significant differences in non-lung cancer mortality and recurrence-to-death time between the two histologic types.