Advances & Insights: Cancer
April 12, 2010
What the news means for you
Ronald McGarry, MD, PhD
SBRT gives lung cancer patients another choice
I have been participating in the studies of stereotactic body radiation therapy (SBRT) for lung cancer since studies began more than 10 years ago. This most current study was a national trial that extended results from our earlier studies to other institutions across the United States in a very carefully controlled way.
This study confirms SBRT is a noninvasive, nonsurgical way to hopefully cure lung cancer, although every patient and every cancer is different. As a result of this and previous studies, SBRT has now become an accepted way to help treat patients with early-stage lung cancer who cannot have surgery to remove the tumor.
"This study confirms SBRT is a noninvasive, nonsurgical way to hopefully cure lung cancer…"
Most patients think surgery is their only choice for treatment of cancer, but based on the findings of this and earlier studies, they now may have another choice. UK is one of only 10 centers nationwide participating in several clinical trials of this emerging form of treatment. These research trials are for patients with small, localized lung cancers (cancer that has not spread) who are either surgical candidates (basically healthy patients) or who are not surgical candidates because their health places them at high risk for surgery.
"UK is also the only center in the country studying the use of SBRT on patients who have [more advanced] lung cancer — stage III."
UK is also the only center in the country studying the use of SBRT on patients who have the most common stage of lung cancer — stage III (more advanced cancers). These patients first undergo the "standard" five to six weeks of radiation treatment. They then get a "boost" with SBRT to the main cancer to see if we can improve patient outcomes.
The SBRT treatments vary but generally are given daily over one to five days. What we are learning is helping us fine-tune treatment based on the excellent results we have already seen. Side effects from this noninvasive treatment with radiation vary depending on the size and location of the cancer, but patients have very few problems generally.
Clinical research into effective new treatments such as SBRT are important as we work to help patients live longer – with a high quality of life – after being diagnosed with lung cancer. UK's Markey Cancer Center and the Brain & Body Radiosurgery Program are in the forefront of this research. We have the expertise and the advanced technology required to be one of the nation's leaders in the use of SBRT for treating lung and other types of cancers.
Dr. McGarry is a pioneer in the use of noninvasive stereotactic body radiation therapy for the treatment of inoperable lung cancer. He is clinical associate professor of medicine and vice chair of radiation medicine in the UK College of Medicine.
New radiation therapy shows promise against lung cancer
A relatively new type of radiation therapy — stereotactic body radiation therapy (SBRT) — appears to rid patients with early-stage disease of lung cancer cells better than conventional radiotherapy. SBRT may also increase a lung cancer patient's life expectancy. Such were the findings of a nationwide study published in JAMA, the Journal of the American Medical Association.
SBRT appears to rid patients with early-stage disease of lung cancer cells better than conventional radiotherapy.
The study, funded by the National Cancer Institute and the Advanced Technology Consortium, looked at 55 patients with early-stage non-small cell lung cancer who could not have traditional surgery because of other medical conditions. Non-small cell lung cancer is the most common type of lung cancer. Surgery is usually recommended to remove the tumor, but conditions such as emphysema and heart disease render the disease inoperable in some patients. Since they can't have surgery, these patients typically either undergo conventional radiation therapy or have no treatment.
How the study was conducted
The Radiation Therapy Oncology Group (RTOG) 0236 trial was designed to improve the two-year primary tumor control rate from 60 to 80 percent and was the first multicenter, cooperative group study in North America to treat patients with medically inoperable early-stage non-small cell lung cancer. The three-year study was conducted from May 2004 to October 2006; data were analyzed through August 2009.
Fifty-five patients over the age of 18 met the criteria for participation and were treated with SBRT. SBRT is a noninvasive treatment that uses multiple tiny beams of super-high doses of radiation shot from all directions to kill the cancer, sparing normal lung and other tissues. Conventional therapy, which uses lower doses of radiation, requires 20-30 outpatient visits over several weeks. Patients in this study underwent SBRT in three treatments over a period of one to two weeks. Patients were followed for four years post-treatment with CT and/or PET scans and pulmonary function tests.
What the study found
"The main finding in this prospective study was the high rate of primary tumor control (97.6 percent at three years)," the researchers concluded. "Primary tumor control is an essential requirement for the cure of lung cancer." Study participants had an overall survival rate of 55.8 percent at three years, and 48.3 percent were disease free. Serious side effects were rare, with significant problems reported in only nine patients who developed rib pain when the cancer was close to the chest wall or patchy sunburn-like reddening of the skin.
"The main finding in this prospective study was the high rate of primary tumor control (97.6 percent at three years)."
— Study authors
This compares to the generally poor outcomes of conventional treatments: conventional radiation therapy fails to control the primary lung tumor in 60-70 percent of patients; without specific treatment, more than half will die from their lung cancer; and the two-to-three year survival rate overall is 20 to 35 percent.
During the period of observation following treatment, 26 patients died. Of those, 10 (18 percent of the study participants) died of lung cancer. Two died from medical treatments unrelated to the study, and five died as a result of other medical conditions such as a stroke, heart attack, emphysema or another cancer. Cause of death in nine patients was unknown.
Researchers noted the study was flawed because they were unable to follow up on the cause of death of nine study participants. Also, the study was dealing with a frail patient population who were unable to undergo invasive procedures. Thus the trial did not use invasive pathological testing to measure the effect of SBRT on tumor control. Diagnostic CT and/or PET scans, which may have been less accurate than more invasive measures, were used instead. This makes it difficult to compare with results of healthier patients undergoing surgery whose lung cancers are monitored with more invasive testing.
A disappointing finding reported by the researchers was the rate of the lung cancer's spreading (metastasizing) outside of the region of the primary lung cancer tumor (22.1 percent at three years) despite overall evidence of high rates of control for the primary lung tumor and surrounding areas. The researchers believe that because the metastases appeared shortly after SBRT, the tumors were not detected by the initial CT and PET scans. This points to the need for early determination of whether a cancer has spread as well as additional treatments (such as chemotherapy) to address the metastasized cancer.
For more information, see:
Stereotactic body radiation therapy for inoperable early stage lung cancer, JAMA, v. 303, no. 11, March 17, 2010
Stereotactic body radiation therapy, UK HealthCare
UK HealthCare Cancer Services - Markey Cancer Center
For more information, or to make an appointment with a UK HealthCare physician, please call UK Health Connection at 1-800-333-8874.