Treatment Timing Tied to Lung Cancer Survival

By David Douglas

NEW YORK MAR 28, 2006 (Reuters Health) - A short time between the first day of chemotherapy and the last day of chest radiotherapy, and hence possibly reduced tumor proliferation, is associated with improved survival in patients with limited-disease small-cell lung cancer (SCLC), researchers report in the March 1st issue of the Journal of Clinical Oncology.

In daily practice, "the time between the start of the treatment, be it chemotherapy or concurrent chemo-radiation, to the end of the chest radiotherapy should be kept as short as possible," lead researcher Dr. Dirk De Ruysscher told Reuters Health. "Delays for whatever reason should be avoided."

Dr. De Ruysscher of University Hospital Maastricht, The Netherlands and colleagues note that without treatment, tumor progression in SCLC is rapid and median survival may be as low as 2 months.

To examine treatment factors that influence survival, the researchers conducted a meta-analysis of 4 phase III trials involving more than 1000 patients for whom 5-year survival data were available. Patients received chest radiotherapy and platinum-based chemotherapy.

The timing of chest radiation and the start of any treatment until the end of chest radiotherapy (SER) was the most important predictor of outcome. There was a significantly higher 5-year survival in patients in the shorter SER arms of the studies (relative risk 0.62).

Five-year survival was more than 20% when the SER was less than 30 days. However, the researchers calculated that each week of extension of the SER beyond that in the study arm with the shortest SER, caused an absolute decrease of 1.83% in 5-year survival.

The novel parameter SER, "which takes into account accelerated proliferation of tumor clonogens during both radiotherapy and chemotherapy," the investigators suggest, "may facilitate a more rational design of combined-modality treatment in rapidly proliferating tumors."

In an accompanying editorial, Drs. Anthony M. Brade and Ian F. Tannock of Prince Margaret Hospital and the University of Toronto, note that the analysis does not provide proof of such repopulation. However, they conclude that the study is important in "drawing attention to repopulation as a potential cause of treatment failure."

SOURCE:

• J Clin Oncol 2006;24:1057-  .