Concurrent cisplatin/etoposide chemotherapy plus twice daily thoracic radiotherapy in limited stage small cell lung cancer: a phase II study

Radiotherapy Fraction in Limited-Stage Small Cell Lung Cancer in the Modern Era: A Systematic Review and Meta-Analysis of 8006 Reconstructed Individual Patient Data

The optimal thoracic radiotherapy (TRT) dose and fractionation for limited-stage small cell lung cancer (LS-SCLC) using modern techniques remain unclear. We conducted systematic review and meta-analyses of the efficacy and safety differences between definitive hypofractionated TRT (HypoTRT), conventional TRT (ConvTRT) and hyperfractionated TRT (HyperTRT), especially in the modern era. Eligible randomized controlled trials (RCTs), real-world cohorts, and single-arm trials published between 1990 and 2021 were identified. Two meta-analyses of overall survival (OS) were conducted: (i) a random-effects meta-analysis based on reconstructed individual-patient data (IPD) of all studies; and (ii) a Bayesian network meta-analysis based on study-level aggregated data (AD) of RCTs. The incidences of severe radiation-related toxicities were compared using the random-effects meta-regression model. Overall, 53 of the 30,031 publications met the inclusion criteria, and a total of 8006 IPD were reconstructed. After adjusting for key treatment variables and stratification by study type, there were no significant differences in the OS rates between the altered fractionation regimens (HypoTRT vs. HyperTRT, aHR [adjusted HR] = 1.05, 95% CI 0.93-1.19; ConvTRT vs. HyperTRT, aHR = 1.00, 95% CI 0·90-1.11; HypoTRT vs. ConvTRT, aHR = 1.05, 95% CI 0.91-1.20). In the modern era, the survival outcomes of all three schedules, while remaining comparable, have improved significantly. Results of the AD-based network meta-analysis were consistent with those of IPD analysis, and HypoTRT was ranked as the best regimen (SUCRA = 81%). There were no significant differences in toxicities between groups when using modern radiation techniques. In the modern era, no significant differences in OS or severe radiation-related toxicities were observed between altered schedules in LS-SCLC. HypoTRT may be associated with moderate and non-significant OS improvements, which should be further confirmed in prospective randomized phase III trials.

Irinotecan plus cisplatin chemotherapy followed by concurrent thoracic irradiation with low-dose weekly cisplatin for limited-disease small-cell lung cancer

A phase II trial of irinotecan and cisplatin (IP) as induction chemotherapy followed by conventional thoracic irradiation concurrent with low-dose weekly cisplatin for limited-disease small-cell lung cancer (LDS-SCLC). Between February 2005 and December 2008, 34 chemotherapy-naïve patients with LD-SCLC were enrolled. Treatment consisted of two 21-day cycles of cisplatin 40 mg/m(2) and irinotecan 80 mg/m(2) intravenously (IV) on days 1 and 8 followed by conventional thoracic irradiation at a dose of 54 Gy concurrent with cisplatin at dose of 20 mg/m(2) weekly then prophylactic cranial irradiation at dose of 30 Gy in 10 fractions for those achieved complete or partial response. Only 33 patients received the treatment protocol, and they were assessed for response and toxicity. After induction chemotherapy, overall response rate was (72.73%). After median follow-up of 27 months, the median survival was 25 months (95% CI, 21.249-28.751) with 1 and 2-year overall survival rates of 83 and 55%, respectively. Median progression-free survival (PFS) was 15 months (95% CI, 10.311-19.689) with a 1- and 2-year PFS of 59 and 38%, respectively. The most common toxicities during induction chemotherapy were neutropenia (81%), thrombocytopenia (69%), and diarrhea (63%) while esophagitis (84%) and pneumonitis (30%) were the most common toxicities during concurrent chemo-radiation. Relapse rate was 61% with distant metastasis in 42% and local recurrence in 26%. This protocol of induction irinotecon-based regimen followed by delayed concurrent thoracic irradiation with low-dose weekly cisplatin is effective with acceptable toxicities. Based on the favorable outcome in this trial, this regimen should be evaluated in a large phase III trial.

The Role of Radiation Therapy in Thoracic Tumors

Radiation plays an important role in the treatment of thoracic tumors. During the last 10 years there have been several major advances in thoracic RT including the incorporation of concurrent chemotherapy and the application of con-formal radiation-delivery techniques (eg, stereotactic RT, three-dimensional conformal RT, and intensity-modulated RT) that allow radiation dose escalation. Radiation as a local measure remains the definitive treatment of medically inoperable or surgically unresectable disease in NSCLC and part of a multimodality regimen for locally advanced NSCLC, limited stage SCLC, esophageal cancer, thymoma, and mesothelioma.

Combined Chemoradiotherapy in Small Cell Lung Cancer

Combined chemoradiotherapy is the established standard of care for limited stage small cell lung cancer; it provides cure in 15% to 25% of patients. Early concurrent therapy imparts a 5% long-term survival benefit compared with sequential therapy. Hyperfractionated delivery of radiotherapy may provide a small incremental benefit when compared with standard fractionation. Radiotherapy dose escalation and reduced radiotherapy volumes are feasible; however, survival benefit has not been confirmed. Cisplatin and etoposide remain the preferred chemotherapy agents. New chemotherapeutic agents and novel treatment approaches are under intense investigation.