Thoracic Radiotherapy Raises SCLC Survival

SAN FRANCISCO—Survival of patients with limited-stage small-cell lung cancer (SCLC) has doubled in the past 2 decades, largely because of advances in thoracic radiation, according to an analysis of more than 2 dozen randomized clinical trials and the SEER database. The findings were presented at the 37th Annual Meeting of the American Society of Clinical Oncology (ASCO abstract 1264).

Pasi Jänne, MD, PhD, of Dana-Farber Cancer Institute and Harvard Medical School, presented the analysis of 26 phase III North American clinical trials performed by cooperative groups. The trials were drawn from a group of 44 trials identified from the SEER database and a MEDLINE search.

The sample included 5,245 patients evaluated in 6 trials of thoracic radiation therapy, 14 trials of chemotherapy regimens, and 6 trials of biologic modifiers. The analysis examined two time periods: 1972 to 1981 and 1982 to 1992 (completed by 1996).

Studies from 1972 to 1981 reported fewer patients per arm: 116 vs 308 for studies from the more recent period. Median response rate was 75% and median survival was 12 months for these earlier studies. The more recent period, 1982 to 1992, showed an 85% response rate and a significantly higher median survival of 17 months (P < .001), Dr. Jänne said.

In the SEER database, there has been a linear 5-month increase in median survival of limited-stage SCLC patients from 1973 to 1996. Since 1975, the 5-year survival of these patients has more than doubled, from 5.2% to 12.2% (P = .0001).

Five of the 26 studies (19%) had a statistically significant prolongation in survival for the experimental vs the control arms, and all five evaluated some aspect of thoracic radiation therapy. Fourteen of 14 chemotherapy studies and 6 of 6 studies of biologic agents demonstrated equivalency between the treatment and experimental arms, Dr. Jänne reported.

Which Studies Should Go Forward?

"A lot of components go into this kind of study. Our goal was to look at outcome and be able to use information from the last 20 years when planning studies in limited-stage SCLC," Dr. Jänne noted.

He pointed out that most of the studies analyzed were negative. "We would like to take this information and develop statistical models that would predict which phase II studies, when taken into the randomized setting, would have a higher likelihood of being positive," he said.

To show a difference in survival, a randomized study requires 300 to 400 patients, he said. "Should every promising pilot study go forward? For all forms of lung cancer, you hit a ceiling with chemotherapy and probably for radiotherapy as well," he said.