Thoracic Radiotherapy Aids Extensive SCLC Survival

Targeting intrathoracic metastases may help patients with extensive-stage small-cell lung cancer

medwireNews: Thoracic radiotherapy should be considered for patients with extensive-stage small-cell lung cancer (SCLC) who respond to chemotherapy, research suggests.

The phase III trial results indicate that adding thoracic radiation to a standard regimen of prophylactic cranial irradiation improves long-term survival and reduces the likelihood of progression in this patient population.

The study results have been simultaneously reported this week at the annual meeting of the American Society For Radiation Oncology in San Francisco, California, USA, and published in The Lancet.

Although overall survival rates after 1 year were not significantly higher in the 247 patients given 30 Gy thoracic radiation over 10 fractions plus cranial irradiation than the 248 patients given only cranial radiation (33 vs 28%), secondary analysis revealed a significant difference after 2 years (13 vs 3%).

This gave a number needed to treat to avoid one death of 10.6, say Ben Slotman, from VU University Medical Center in Amsterdam, the Netherlands, and co-authors.

Thoracic radiation was also associated with a reduced risk of disease progression at 6 months (hazard ratio=0.73) and improved 6-month progression-free survival (24 vs 7%). In addition, thoracic radiation significantly reduced the risk of isolated intrathoracic disease progression (19.8 vs 46.0%) and reduced the likelihood that the first site of progression would be the thorax (41.7 vs 77.8%).

“The effect of thoracic radiotherapy on overall survival in this study opens the way for further studies assessing higher doses of radiation and using advanced delivery techniques”, the researchers say.

In an accompanying comment, Jan van Meerbeeck, from Ghent and Antwerp University in Belgium, and David Ball, from University of Melbourne in Victoria, Australia, say that the rationale for the study was sound and note that the radiotherapy protocol is easy to provide at low cost even in modestly resourced radiotherapy departments.

Considering which extensive-stage SCLC patients may benefit most from thoracic radiotherapy and the optimal scheduling of such treatment, they conclude: “We await the results of a similar US trial in which patients with metastatic small-cell lung cancer are randomly assigned to prophylactic cranial irradiation with or without consolidative extracranial radiotherapy to locoregional and residual metastases.”

References

Slotman B, van Tinteren H, Praag J,  et al. Use of thoracic radiotherapy for extensive stage small-cell lung cancer: a phase 3 randomised controlled trial. Lancet 2014; Early online publication 14 September. doi:10.1016/S0140-6736(14)61085-0

van Meerbeeck J, Ball D. Small-cell lung cancer: local therapy for a systemic disease? Lancet 2014; Early online publication 14 September. doi:10.1016/S0140-6736(14)61252-6

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