Influence of maintenance therapy on incidence of 2nd line therapy and OS in NSCLC IV
Introduction: One of the strongest rationale for maintenance therapy in NSCLC is the fact that exposure to 2nd line therapy is only 40 – 60% in clinical trials in specialized treatment centers. Even with follow-up intervals of 6 weeks, the 2nd line treatment rate does not seem to increase. We analyzed the exposure of 2nd line therapy as well as OS and PFS in patients with stage IV NSCLC in the subgroups no 2nd line, 2nd line after maintenance and 2nd line without maintenance therapy.
Methods: All primary lung cancer cases stage IV in the lung cancer center were analyzed based on the documentation files between 2009 and 2013. Patients were followed-up between 1st and 2nd line therapy every 6 – 8 weeks according to S3 guidelines. Patients with EGFR+, ALK+ or ROS1+ were excluded from the analysis.
Results: 221 patients were diagnosed with NSCLC IV (UICC7), or had systemic relapse of localized disease and were treated with 1st line therapy for metastatic disease. Of these, 160 (72%) received 1st line combination therapy with Carboplatin, 50 (23%) with Cisplatin and 11 (5%) with platin-free single agent therapy. 45 (19%) of all patients received maintenance therapy, most of them with bevacizumab. Of 221 patients, 188 (85%) progressed after 1st line therapy or 1st line and maintenance therapy. 101/157 (64%) of non-maintenance therapy patients received 2nd line therapy, 56 patients (35%) did not. Of 31 patients receiving maintenance therapy and requiring 2nd line therapy, 27 (89%) received 2nd line therapy. Reasons for not obtaining 2nd line therapy were captured and were manifold. Survival analyses showed differences regarding overall survival (median survival 21 (maintenance and 2nd line) vs. 14 (1st and 2nd line) months) but no relevant differences regarding progression free survival on 2nd line (median 2 months).
Conclusion: In a certified lung cancer center and stringent follow-up every 6 to 8 weeks, 1/3 of patients do not receive 2nd line therapy because of various reasons. The application of maintenance therapy raises the chances of receiving 2nd line therapy and increases overall survival whereas progression free survival is not affected.