Bi-weekly irinotecan is an effective and convenient regimen in the treatment of relapsed or refractory small cell lung cancer.

Background: Despite initial dramatic responses, metastatic small cell lung cancer (SCLC) invariably recurs. Irinotecan is one of the active agents for patients with recurrent SCLC. In the second line, weekly or three-weekly irinotecan regimens have been adopted, however, the optimal dose and schedule is not defined. In our institution, we use a bi-weekly regimen of irinotecan. In this study, we aimed to investigate the safety and efficacy of the bi-weekly irinotecan in the second- or third-line treatment of SCLC patients.

Methods: The study population consisted of advanced stage SCLC patients who were followed at Hacettepe University Cancer Institute between January 2007 and March 2021 and received salvage irinotecan 180 mg/m every two weeks, following progression after platinum-etoposide treatment.

Results: One hundred patients were included. At diagnosis, nineteen patients (19%) had limited stage and 81 patients (81%) had extensive stage SCLC. Objective response rates (ORR) were 44.6% and 46.2% for patients who received irinotecan treatment in second line, and in third line, respectively. Seventeen percent of all the patients had grade 3 and above adverse events during irinotecan treatment. In our study, 45.8% of patients were able to complete at least 6 cycles of irinotecan treatment and 69.8% were able to receive at least 3 cycles of irinotecan treatment without any dose interruption or reduction.

Conclusions: Irinotecan 180 mg/m every two weeks appears to be safe and effective in the 2nd- and 3rd-line treatment of advanced stage SCLC. Bi-weekly administration allows G-CSF prophylaxis in between doses, leading to an uninterrupted administration.