Obesity Significantly Increases Side Effects of Stereotactic Body Radiation Therapy in Lung Cancer Patients

Obesity Significantly Increases Side Effects of Stereotactic Body Radiation
Therapy in Lung Cancer Patients

CHICAGO, Nov. 2 /PRNewswire-USNewswire/ -- Obesity, not the amount of
radiation given, is the greatest factor in whether early-stage lung cancer
patients develop chest wall pain after receiving stereotactic body radiation
therapy to the chest wall, with obese patients being more than twice as likely
to develop chronic pain compared to those who have less body weight, according
to a first-of-its-kind study presented Tuesday, November 3, 2009, at the 51st
Annual Meeting of the American Society for Radiation Oncology (ASTRO).

Researchers studied other factors associated with obesity, such as diabetes,
to find out why obesity in patients increased chest wall pain. Findings show
that obese patients who are diabetic are over three times more likely to
develop chest wall pain after receiving stereotactic body radiation therapy to
the chest wall, compared to patients who do not have diabetes.

"The study shows that physiological factors, such as obesity and diabetes, can
play a major role in the development of radiation-related toxicity," James
Welsh, M.D., lead author of the study and a radiation oncologist at the M.D.
Anderson Cancer Center in Houston said. "This is a surprising finding, since
most side effects of radiation treatment are based on the amount of normal
tissue that is treated and the volume of the dose."

The main purpose of the study was to find out what the highest amount of
radiation that could be delivered to the chest wall using a specialized type
of radiation treatment called stereotactic body radiation therapy (SBRT)
without patients developing the late side effects of pain and skin reactions.
The study shows that patients who receive a high dose of radiation to cancer
close to the chest wall (in the amount of 35 gray (Gy)) have an increased
chance of having pain and skin reactions, compared to those who have a lower
radiation dose.

SBRT is a specialized type of external beam radiation therapy that pinpoints
high doses of radiation directly on the cancer in a shorter amount of time
than traditional treatments. Cancer centers often call the treatments by the
brand names of the manufacturers, including Axesse, CyberKnife, Gamma Knife,
Novalis, Primatom, Synergy, X-Knife, TomoTherapy and Trilogy. Treatment is
typically delivered in 1 to 2 weeks, instead of a period of 6 to 8 weeks.

"SBRT is now being investigated as a replacement to surgery for early-stage
lung cancer. If this non-invasive technique is to replace surgery, not only
does it need to be effective, but also safe," Dr. Welsh said. "Since this
study shows that a 35Gy dose of radiation, obesity, and diabetes increase the
risk of developing late negative side effects after high dose radiation, then
we can take steps to reduce these side effects."

The study involved 265 patients with tumors within less than 2.5 centimeters
of the chest wall, who were treated with SBRT between August 2004 and August
2008. Of these patients, 39 percent developed skin toxicity, while six percent
developed acute pain and 22 percent developed chronic pain. In patients who
are considered obese, diabetes mellitus was found to be a significant
contributing factor in the development of chest pain.

For more information on cancer and stereotactic radiation therapy, visit
www.rtanswers.org.

The abstract, "Skin Toxicity And Pain In Patients Treated With Stereotactic
Body Radiotherapy," will be presented at a scientific session at 3:20 p.m. on
Tuesday, November 3, 2009. To speak to the lead author of the study, James
Welsh, M.D., please call Beth Bukata or Nicole Napoli November 1-4, 2009, in
the ASTRO Press Room at McCormick Place West at 312-791-7005 or 312-791-7006.
You may also e-mail them at bethb@astro.org or nicolen@astro.org.

SOURCE American Society for Radiation Oncology

Beth Bukata, bethb@astro.org, or Nicole Napoli, nicolen@astro.org,
800-962-7876, Press Room Phone: Nov. 1-4, +1-312-791-7005, or +1-312-791-7006,
After Hours: +1-703-474-0940, both of American Society for Radiation Oncology