Concurrent radiation therapy in Small Cell Lung Cancer (SCLC) LD; Preliminary results from a Dutch pilot study

Phase I study of hypofractionated dose-escalated thoracic radiotherapy for limited-stage small-cell lung cancer

PURPOSE

To determine the maximal tolerated dose of hypofractionated thoracic radiotherapy with concurrent chemotherapy for limited-stage small-cell lung cancer patients.

METHODS AND MATERIALS

Three radiotherapy regimens were used. Radiotherapy was given in two phases: patients initially received 20 Gy in 10 fractions to gross tumor plus uninvolved mediastinal nodes, followed by a boost to gross disease of 30, 38, or 42 Gy in 15 fractions. Radiotherapy was planned with conformal techniques. All patients received four cycles of cisplatin (25 mg/m2) and etoposide (100 mg/m2) chemotherapy. Radiotherapy commenced with Day 1 of Cycle 2 of chemotherapy. All complete/near-complete responders were offered prophylactic cranial irradiation. The maximal tolerated dose of radiotherapy was based on the dose that caused unacceptably high rates of radiotherapy-related toxicity.

RESULTS

Thirteen patients were accrued. All patients who commenced radiotherapy received all prescribed chemo- and radiotherapy. There were no treatment-related deaths. There was one Grade 3 acute nonhematologic toxicity in the 50-Gy group. Of the 6 patients given 58 Gy, 3 experienced acute Grade 3 esophagitis. With a median follow-up of 7 months, median overall survival was 9.5 months.

CONCLUSIONS

The maximal tolerated dose of thoracic radiotherapy with concurrent chemotherapy on this trial was 50 Gy in 25 daily fractions.

Thoracic radiation therapy for limited-stage small-cell lung cancer: unanswered questions

The role of thoracic radiation therapy (RT; TRT) is now established in the management of limited-stage small-cell lung cancer (SCLC). There is increasing evidence in the literature in favor of early concurrent chemoradiation therapy, and a gold standard of care for patients with a good performance status is twice-daily TRT (45 Gy in 3 weeks) with concurrent cisplatin/etoposide. Five-year survival rates > 20% can be expected with this combined-modality approach. Although current clinical trials are exploring the efficacy of new chemotherapeutic strategies for the disease, essential questions related to the optimization of TRT remain unanswered. In particular, the optimal RT dose, fractionation, and treatment volume have not been defined. This review highlights the need for well-designed multinational trials aimed at the optimization and standardization of RT for limited-stage SCLC. These trials should integrate translational research studies to investigate the molecular basis of RT resistance and to develop biomarker profiles of prognosis.

Thoracic Radiotherapy for Limited-stage Small-cell Lung Cancer: Controversies and Future developments

Thoracic radiotherapy has an established role in the management of limited-disease small-cell lung cancer (LD SCLC). However, essential questions relating to the optimisation of thoracic radiotherapy remain unanswered, including volume of irradiation, optimal total dose, fractionation, timing and sequencing of radiation. This review highlights the need for well-designed multi-national trials aimed at the optimisation and standardisation of radiotherapy for LD SCLC.

Thoracic radiotherapy for limited-stage small cell lung cancer: issues of timing, volumes, dose, and fractionation

Although meta-analysis of randomized trials comparing chemotherapy alone versus chemotherapy plus thoracic irradiation demonstrated that thoracic radiotherapy reduced mortality by 14%, this analysis probably underestimates the effect of optimally delivered thoracic irradiation integrated with appropriate chemotherapy. However, there remains much debate as to the optimal timing of the radiotherapy and the radiotherapy volume, dose, and fractionation. Theoretically, early use of radiotherapy should reduce the probability of chemotherapy and radiation resistance, accelerated repopulation, and metastatic events. Deferred or sequential radiotherapy potentially allows smaller radiotherapy fields. Of the seven randomized controlled trials examining timing, only those with early chemoradiation have 5-year survival rates in excess of 20%. The "chemoradiation package" can be defined as the time from the start of chemotherapy until the completion of radiotherapy. The best median survival and long-term survival rates have been observed in trials with a chemoradiation package time of less than 6 weeks. Protocols combining chemotherapy and radiotherapy must respect radiobiologic principles concerning the time factor derived from radiotherapy fractionation studies.