March 16, 2010 -- An experimental type of highly focused radiation therapy
may control inoperable lung cancer tumors and help people with the deadly
disease live longer.
A new study shows stereotactic body radiation therapy (SBRT) effectively
controlled more than 87% of early-stage inoperable non-small-cell lung cancer
tumors for up to three years. Researchers say that rate of tumor control is
more than double that found with conventional radiation treatment for
inoperable lung cancer.
Researchers say surgical removal of tumors is the standard treatment for
early-stage lung cancer, but some people are not candidates for surgery due to
other coexisting illnesses such as emphysema and heart disease.
In these situations, the lung cancer tumor is deemed inoperable and
conventional radiation therapy or observation without cancer treatment is
offered. Neither option is considered ideal.
"Conventional radiotherapy fails to durably control the primary lung tumor
in 60 percent to 70 percent of patients. More than half of patients ultimately
die specifically from progressive lung cancer with observation, and 2-year
survival is less than 40 percent with either approach," write researcher Robert
Timmerman, MD, of the University of Texas Southwestern Medical Center, Dallas,
and colleagues in the Journal of the American Medical Association.
In the study, researchers evaluated the safety and effectiveness of SBRT in
treating 55 people with early-stage but medically inoperable lung cancer.
SBRT is a noninvasive type of cancer treatment in which many small, highly
focused radiation beams are used to deliver concentrated doses of radiation to
tumor targets over a series of one to five treatments.
Three years after the treatment, the study showed that 28 participants had a
complete response to the therapy and 21 had a partial response. Fourteen
participants had recurrence of cancer.
Overall, the rate of complete plus partial response after therapy was 89%.
Disease-free survival and overall survival three years after treatment were
48.3% and 55.8%, respectively.
Nineteen participants (16.3%) experienced significant but not deadly
treatment-related side effects.
This type of radiation therapy has not yet been approved by the FDA as a
lung cancer treatment, but this study brings it one step closer. The next step
is a clinical trial to evaluate the therapy in a larger number of patients and
determine the proper dosage for maximum benefit and minimal risk.