Benefits of Etoposide Maintenance Therapy for Patients With Extensive SCLC Who Experienced PR/CR/SD After 4-6 Cycles of First-Line Chemotherapy With Etoposide Plus Cisplatin/Carboplatin

Abstract

Background: The clinical remission period of small cell lung cancer was shorter after the first-line treatment. Aim: To observe whether oral etoposide maintenance therapy can improve the progression-free survival (PFS) in patients with lung cancer who experienced complete remission (CR), partial remission (PR), and disease stabilization (SD) after 4-6 cycles of first-line chemotherapy with etoposide plus cisplatin/carboplatin. Methods: A retrospective analysis was performed on patients with ED-SCLC who were treated with etoposide (100 mg/d, iv.gtt days 1-5 with a cycle length of every 21 days) plus 4-6 cycles of cisplatin/carboplatin chemotherapy during the period from 1 January 2014 to 31 December 2016 at the Cancer Hospital affiliated with Zhengzhou University. All the patients were divided into 2 groups based on the criteria whether they had gone through maintenance therapy with etoposide: nonmaintained treatment group (NT), and maintenance treatment group (TH). The maintenance treatment group was further subdivided into the 25 mg subgroup (group A) and the 50 mg subgroup (group B) according to the maintenance dose. Analysis of 1-year progression-free survival (PFS) was conducted using the Kaplan-Meier method and Cox proportional hazards model. PFS1 was defined as the first day of first-line treatment until the disease progressed or the last follow-up time. PFS2 was defined as the first day of etoposide capsule treatment until disease progression or the last follow-up time. Results: A total of 85 patients were enrolled in this study; there were 50 patients in the NT group (58.8%) and 35 patients in the TH group (41.2%). In the TH group, there were 10 (28.6%) in the 25 mg subgroup (group A) and 25 (71.4%) in the 50 mg subgroup (group B). Detailed patient information and tumor-related parameters are shown in Table 1. For all patients, the median PFS1 in the first-line regimen with either the cisplatin or carboplatin group was 6.5 months (95% CI: 5.870-7.130) and 6.4 months (95% CI: 5.970-6.970) respectively ( P = 0.0551). Median progression-free survival for all patients and the median PFS for patients of the TH group were 6.5 months (95% CI: 6.138-6.861) and 7.2 months (95% CI: 6.702-7.698) respectively; the median PFS for the NT group, subgroup A, and subgroup B were 5.7 months (95% CI: 4.862-6.478), 6.7 months (95% CI: 6.390-7.010), and 7.4 months (95% CI: 6.386-8.474), respectively ( P = 0.0043). Median PFS2 was 2.400 months for maintenance treatment patients; the median PFS2 in the 25 mg and 50 mg groups was 2.100 months (95% CI 1.690-2.510 months) and 3.030 months (95% CI 1.937-4.123 months), respectively ( P = 0.0309). Conclusion: Use of etoposide capsules to maintain chemotherapy can significantly prolong the progression-free survival (PFS) of CR, PR, and SD in patients with extensive SCLC and improve 1-year survival; a 50-mg dose is better than 25 mg.