Stereotactic body radiation therapy safe and effective way to treat early stage lung cancer in medically inoperable patients

Nov 1 2005

Lung cancer patients with extenuating health problems may have an alternative to traditional radiation therapy through a lung-sparing procedure pioneered at the Indiana University School of Medicine.

Patients with early stage non-small cell lung cancer responded well to high doses of radiation administered through extracranial stereotactic body radiation therapy, according to an article published in the Nov. 15 issue of the International Journal of Radiation Oncology, Biology and Physics.

The Phase I clinical trial, which looked at the safety and efficacy of the procedure, treated 47 individuals with early-stage cancer who normally would have received surgery and radiation therapy. These patients had extenuating health problems that made them poor candidates for surgery.

"Patients receiving the extracranial stereotactic body radiation were spared the trauma of surgery but were able to undergo higher doses of radiation for a shorter period of time than the standard treatment," said Ronald C. McGarry, M.D., Ph.D., principal investigator of the study and an IU professor of radiation oncology. "I think of the treatment as a lung-sparing approach, and this study shows it is one of the most effective options for lung cancer patients for whom surgery is not an option."

Using precision mapping of the tumor and a sterotactic body frame that keeps the patient virtually immobile, physicians escalated radiation dosages, directing it all to the tumor site and sparing health surrounding tissue. The mapping allows physicians to administer higher doses of radiation while safeguarding uninvolved tissue and organs.

Patients received three treatments in seven to 10 days versus standard therapy of 35 treatments over a six-week period. Physicians treated patients in this study with escalating doses of radiation therapy and were surprised that the careful planning resulted in patients tolerating very intense treatment with few long-term side effects. Only one patient in the higher dose groups had a return of the treated cancer, although 14 of the 47 patients developed spread (metastasis) of their lung cancer.

Using the high doses achieved in the first phase of the research, a second trial of more than 70 patients was completed over a year ago. A median follow-up of two years revealed only three of the patients had a cancer recurrence. These optimistic preliminary results of the second trial were reported at the October meeting of the American Society for Therapeutic Radiation Oncology in Denver, Colo. Final analysis of this data will be completed in 2006.

Early cancer spread is not uncommon with lung cancer, said Dr. McGarry. As a pioneer in extracranial stereotactic body radiation therapy, the IU School of Medicine has developed a third clinical trial now underway. Patients with early stage lung cancer will receive the intense therapy to control their lung cancer followed by mild chemotherapy in an effort to control microscopic disease which can spread early in the process. Dr. McGarry said he is hopeful this trial will produce even greater cure rates.

"Stereotactic body radiation therapy is proving to be a safe and effective way to treat early stage lung cancer in medically inoperable patients," said Dr. McGarry. "This treatment may become standard treatment for frail patients and an alternative to lobectomy for other patients who do not have the medical complications."