Researchers from the Cleveland Clinic in Cleveland, OH presented data at the 2014 Chicago Multidisciplinary Symposium in Thoracic Oncology, demonstrating that “stereotactic body radiotherapy (SBRT) can now be considered as standard of care for medically inoperable patients with early stage lung cancer,” according to Gregory M.M. Videtic, lead study author, in a recent press release.
Data collected from an institutional patient registry on SBRT treatments in 300 patients suffering with medically inoperable early stage lung cancer from 2003 to 2012 analysis showed that this technique is an excellent solution for inoperable patients.
Among the 300 patients, there were 340 lesions (tumors) treated between October 1, 2003 and December 31, 2012 at the Cleveland Clinic. The Cleveland Clinic is one of the few U.S. institutions that were early adopters of SBRT technology for lung cancer patients. Patients had a median age of 74 years, a median Karnofsky Performance Status (KPS) of 80, and could not be operated on because of their medical conditions, wherein chronic obstructive pulmonary disease (COPD) was the most common obstacle (62 percent). Patients were followed up for 17.4 months on average, and 46.7 percent of the patients were alive by that time (140 patients). The median tumor diameter was 2.4 cm and 36.3 percent of the patients (meaning 123 patients) had neither biopsy nor non-diagnostic biopsy. Also, 15 percent of the patients (45) received 2 or more SBRT treatments.
Each individual patient’s anatomy needs to be accurately mapped and breathing motion has to be studied in order to perform SBRT and damage the smallest amount of healthy tissues as possible. All patients were treated uniformly using a vacuum-bag to immobilize and compress the abdominal region and to limit breathing effects. Through the combination of three CT images while at rest, in full inhalation and full exhalation the internal target volume (ITV) of the tumors was calculated to optimize radiation and its targeting.
Early and late toxicity were measured: the overall rate of any toxicity was 13 percent (meaning 45 patients) and most patients had minimal toxicities (grade 2 or less); there were not cases of grade 4 or 5. According to the press release, “The most common occurrences were chest wall toxicity, 7.7 percent, and pneumonitis (inflammation of the lung tissue), 4.1 percent. The toxicity rate for the 115 lesions classified as “central” tumors, according to the RTOG 0813 definition of “within or touching the zone of the proximal bronchial tree or adjacent to mediastinal or pericardial pleura,” vs. non-central tumors (225 lesions) was 15.5 percent (18 lesions) vs. 11.7 percent (27 lesions).”
Five years after the treatment and in patients with central tumors, local control was 79 percent, distant metastases-free 49.5 percent, failure-free rates 37.3 percent and overall survival rate 18.3 percent. For patients that had non-central tumors, local control was 75.4 percent, distant metastases-free 56.7 percent, failure-free rates 34.3 percent and overall survival 20.3 percent. “Rates of local, lobar (within a whole lobe of the lung) and regional node failure for lesions were 11.2 percent, 4.1 percent and 13.5 percent, respectively,” as described in the press release.
“Since our results indicate no unusual long term side effects, we are hoping to extend the potential uses of this therapy to more-fit, operable lung cancer patients whose cancer has not spread outside of the lung and to collaborate with other institutions on conducting such a clinical trial. SBRT could provide a more minimally invasive procedure than surgery, with fewer side effects and improved patient outcomes,” said the author Gregory M.M. Videtic, MD, a radiation oncologist at the Cleveland Clinic Foundation and associate professor of radiation oncology at the Cleveland Clinic Lerner College of Medicine, Case Western Reserve University.