The addition of thoracic radiotherapy to prophylactic cranial radiation significantly extended survival among patients with extensive-stage small-cell lung cancer, according to results of a randomized phase 3 trial.
The analysis included 498 patients treated at 42 hospitals in the United Kingdom, Netherlands, Norway and Belgium. All patients had extensive stage-SCLC with a WHO performance score of 0 to 2. All patients demonstrated a response to chemotherapy.
Ben J. Slotman, MD, PhD, of the department of radiation oncology at VU University Medical Center in Amsterdam, and colleagues randomly assigned 247 patients to receive thoracic radiotherapy (30 Gy in 10 fractions). The other 248 patients received no radiotherapy. All patients underwent prophylactic cranial irradiation.
OS at 1 year served as the primary outcome measure in the intention-to-treat population. PFS served as the secondary outcome. Median follow-up was 2 years.
OS at 1 year was higher among patients who underwent thoracic radiotherapy (33% vs. 28%), but the difference was not statistically significant. However, OS at 2 years was significantly higher in the thoracic radiotherapy group (13% vs. 3%).
Slotman and colleagues also determined thoracic radiotherapy reduced risk for disease progression (HR=0.73; 95% CI, 0.61-0.87). Six-month PFS rates were 24% in the thoracic radiotherapy group and 7% in the control group.
Researchers reported no difference in serious adverse events between arms. The most common grade ≥3 adverse events were fatigue (11 cases for thoracic radiotherapy vs. 9 for controls) and dyspnea (three cases for radiotherapy vs. four cases for controls).
“Refreshingly, the radiotherapy in Slotman and colleagues’ study was not technically complex and it would be easy to provide at low cost in even the most modestly resourced radiotherapy departments,” Jan P. van Meerbeeck, MD, PhD, professor at Ghent and Antwerp University in Belgium, and David Ball, MD, deputy director of radiation oncology and cancer imaging and chair of the lung service at Peter MacCallum Cancer Centre in Melbourne, Australia, wrote in an accompanying editorial.
“Should Slotman and colleagues’ results therefore require oncologists to consider thoracic radiotherapy in all responders with extensive disease, as recommended by the authors? Only for selected patients,” van Meerbeeck and Ball wrote. “For example, would thoracic radiotherapy be appropriate in a responder who still has large-volume liver metastases and minimal intrathoracic disease burden? Should we bring forward thoracic radiotherapy and administer it at an accelerated schedule and during chemotherapy?”
Additional details about patient-reported outcomes would have helped answer certain research questions, van Meerbeeck and Ball wrote.
“We await the results of a similar US trial in which patients with metastatic SCLC are randomly assigned to prophylactic cranial irradiation with or without consolidative extra cranial radiotherapy to locoregional and residual metastases,” they wrote.
For more information:
- Slotman BJ. Lancet Oncol. 2014;doi:10.1016/S0140-6736(14)61085-0.
- van Meerbeeck. Lancet Oncol. 2014;doi:10.1016/S0140-6736(14)61252-6.
Disclosure: The study was funded by the Dutch Cancer Society, Dutch Lung Cancer Research Group, Cancer Research UK, Manchester Academic Health Science Centre Trials Coordination Unit and the UK National Cancer Research Network. The researchers report no relevant financial disclosures.