A Phase II Study of Accelerated Hyperfractionated Thoracic Radiotherapy With Dose Escalation to 54 Gy With Concurrent Cisplatin and Etoposide for Limited-Stage Small-Cell Lung Cancer: Long-Term Results at a Single Institution.

[PURPOSE] The combination of 45 Gy accelerated hyperfractionated thoracic radiotherapy (AHF-TRT) and concurrent chemotherapy is the standard treatment for limited-stage small-cell lung cancer (LS-SCLC). However, the optimal dose and fractionation remain controversial. We herein report the long-term results of a phase II study investigating the utility of dose escalation to 54 Gy in AHF-TRT for LS-SCLC.

[METHODS AND MATERIALS] We enrolled patients with pathologically confirmed LS-SCLC. The radiation dose was 54 Gy, delivered in 36 fractions over 3.6 weeks. All patients were treated with 3D-CRT with multiple fields to reduce the elevated dose volume to the surrounding tissues. The chemotherapy regimens consisted of either cisplatin and etoposide or carboplatin and etoposide. All patients were evaluated for overall survival (OS), progression-free survival (PFS), and nonhematological toxicity.

[RESULTS] Between 2013 and 2019, 21 patients were enrolled in this study. All the patients were assessed for their response and toxicities. The median age was 70 years and 15 patients were male, while 6 were female. The median follow-up period of all patients was 57.3 months. The 2- and 5-year OS rates were 85.7% and 47.6% respectively. The 2- and 5-year PFS rates were 52.3% and 47.6% respectively. No patient experienced grade ≥ 3 nonhematological adverse effects either during treatment or in follow-up.

[CONCLUSIONS] In this phase II study, AHF-TRT of 54 Gy resulted in a good OS and PFS without increasing severe toxicities. These outcomes suggest that dose escalation to 54 Gy may be a promising radical treatment for LS-SCLC.