Disease relapse is common in patients with non-small-cell lung cancer (NSCLC) after surgery, highlighting the need for treatment optimization in the adjuvant setting. Now, the results of the SELECT trial demonstrate the potential of adjuvant erlotinib, an EGFR tyrosine-kinase inhibitor (TKI), in patients with EGFR-mutated NSCLC.

In this study, 100 patients with resected stage IA–IIIA EGFR-mutant disease received erlotinib for a median duration of 23 months. 2-year disease-free survival (DFS), the primary end point, was 88% (95% CI 80–93%), a value significantly higher than that of a historical control group of untreated patients (76%; P = 0.0047). 5-year DFS was 56%, and 5-year overall survival was 86%.

Disease recurrence occurred in only 4 patients during treatment but in 36 patients after stopping treatment (the median time to recurrence was 25.4 months after cessation). Of these 40 patients, 26 had a new course of erlotinib for a median duration of 13 months; their outcomes were not reported owing to a lack of formal radiographic measurements.

“In this and other studies, very few recurrences occurred during treatment with EGFR TKIs, which is encouraging, but after stopping erlotinib the recurrence rate is similar to what we would expect without adjuvant treatment, only delayed by therapy,” explains principal investigator Nathan Pennell, adding “trials testing longer treatment durations, such as the ADAURA trial of osimertinib, are underway.”

Dose reductions were required in 40% of patients. No grade 4–5 adverse events were reported; the toxicities observed were those commonly associated with erlotinib (rash, diarrhoea, dry skin or fatigue, among others).

“Ultimately, I believe that adjuvant EGFR-targeted therapy will be the optimal strategy. In the future, we will use more-effective and less-toxic drugs to improve treatment adherence, and we will test both earlier initiation and longer treatment durations,” concludes Pennell.