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A ray of hope was presented at this year's ASTRO annual meeting for patients with early-stage lung cancer who are too sick to undergo surgery. Emerging evidence indicates that a specialized form of radiation therapy called stereotactic body radiation therapy (SBRT) can kill tumors with almost no recurrence of cancer at the site of treatment after three years.

The prospective trial involved 59 inoperable non-small cell lung cancer patients undergoing SBRT, who, due to co-morbidities like stroke or heart disease, were too medically frail for surgical resection of their tumors. Analyzed third year data showed that only one patient experienced a recurrence of cancer at the treated site and, generally, SBRT presented the best possible treatment for these patients when compared to conventional radiation therapy.

"The study confirms that SBRT should now be considered a standard treatment," says Robert D. Timmerman, M.D., a radiation oncologist at the University of Texas Southwestern Medical Center in Dallas and lead author of the Radiation Therapy Oncology Group study.

"We were pleasantly surprised that with the mature data it was actually a 98 percent control rate at the primary site, which meant that out of the 59 patients enrolled, only one patient experienced a recurrence of their tumor by three years," Dr. Timmerman said. "This is the highest local control rate that we've seen in such RTOG trials."

Despite having other life-threatening illnesses, 56 percent of the patients were still alive at the conclusion of the three-year study. In fact, lung cancer was the cause of death for fewer than 20 percent of those who died, and those cases typically involved further metastases that had not been caught during initial screening.

The results of this study may lead to further trials in which patients with moderately operable non-small cell lung cancer are treated with SBRT to gauge how the treatment measures up to surgery.

"We're not saying that we think [SBRT] will unseat surgery necessarily, but there might be patients that would prefer an option, or subsets of patients who would be better treated with this therapy," said Dr. Timmerman.

Conventional radiation therapy for these patients currently involves treatment sessions delivering radiation in low doses spanning a period of six to eight weeks for a total radiation dose of about 60 Gy. Timmerman said that only 30 to 50 percent of tumors treated with conventional therapy are eradicated and do not recur at the original site of treatment, which is discouraging.

SBRT involves very precise, high-dose, hypo-fractionated treatments, meaning the same total dose of 60 Gy are treating the cancer, but therapy occurs in fewer sessions and in much higher doses of radiation per session. This is possible because the external radiation beam in SBRT is conforming to the shape and location of the tumor, sparing surrounding healthy tissues. For this form of lung cancer, SBRT can be administered in three outpatient treatments lasting about an hour, with the entire treatment series completed in about one to two weeks.

"[SBRT has shown] considerably better results than what we've seen in historical treatments," said Timmerman. "That's probably the first significant change in the standard of care for this group of patients in the last 50 years."

This treatment has not only been found to be effective, but it also presents an opportunity to improve the lives of very sick patients who oftentimes must travel to distant cancer centers to receive treatment. SBRT could become not only a life-extending treatment in these cases, but it could also save patients time and money and reduce the psychological distress associated with treatment, said Dr. James Welsh, a radiation oncologist from M.D. Anderson Cancer Center in Houston, TX.

"The vast majority of my patients come from a different state or part of the world," said Dr. Welsh. "They are in a hotel room while I'm doing the treatment. If we can do the treatment in one week and get them back home, that's a dramatic improvement in their quality of life."

Dr. Welsh was presenting another study involving correlations between SBRT-related toxicity and lung cancer patients who were found to be obese or who were diagnosed with diabetes mellitus. Dr. Welsh suggested that these patients might experience more skin toxicity and chest pain, warranting further study and possible changes in treatment planning for these patients.