Simultaneous use of chemotherapy and high-dose radiotherapy has produced encouraging results in the treatment of limited-stage small-cell lung cancer, according to a phase II study presented Tuesday at the 2009 American Society for Radiation Oncology (ASTRO) meeting in Chicago.
Small-cell lung cancer is an aggressive cancer that accounts for about 20 percent of lung cancers.
"Over the past few years, we have made significant progress by giving concurrent chemotherapy and thoracic radiotherapy, as well as prophylactic cranial radiotherapy," said the study's lead author Ritsuko Komaki, MD, professor and program director of lung cancer research and thoracic radiation oncology and the department of radiation oncology at the University of Texas, M. D. Anderson Center. "However, five-year survival in limited stage small-cell lung cancer is still only 26 percent, and the likelihood of recurrence and metastasis is still too high."
Patients with small-cell lung cancer were treated with thoracic radiotherapy accelerated slowly over a three-week period, followed by two weeks of higher radiation twice daily for five weeks. At the same time, four cycles of chemotherapy were administered.
The intent of the study was to increase radiation levels during concurrent chemotherapy without increasing damage to normal tissue, which conflicted with previous studies conducted by M.D. Anderson.
During the median follow-up time of 19 months, 41 percent of patients experienced complete response, and another 39 percent had partial response. Despite the higher radiation dose, the rate of acute severe esophagitis was significantly lower than the previous study, 18 percent versus 27 percent, respectively.
However, at 36.6 percent, the two-year survival rate did not improve. In addition, while local control of the disease was excellent--80 percent--the majority of patients still developed distant metastasis, Komaki said.
"This research is important because it achieved a high level of control of the disease while minimizing damage to the esophagus," according to Komaki.
Komaki said further research is needed, possibly including a cycle of induction chemotherapy before concurrent treatment. Improved systemic treatment and staging work-ups are needed too, she said. The new study has been adapted by a randomized intergroup trial that will enroll 700 patients in multiple sites in the United States. The research will compare three radiation dose levels and treatment duration times.