Patients reported decreased pain and improved breathing following treatment of their hilar tumors with robotic radiosurgery in a study by Lombardi Comprehensive Cancer Center researchers, who caution, though, that the improvement does not increase survival. Nevertheless, they say, the study, presented at the American College of Chest Physicians Annual Meeting, represents the first of its kind to document the use of radiosurgery for hilar tumors and presents a novel therapy option.
The team, led by Brian Collins, MD, a radiation oncologist at Lombardi, reviewed the medical records of patients diagnosed with inoperable primary and metastatic hilar lung tumors, which abut or invade the mainstem bronchus. All the patients in the study were treated with five courses (30 to 40 Gy in 5 fractions) of radiotherapy using CyberKnife. Imaging studies with a combined PET/CT scan were performed at three- and six-month follow-up intervals to track tumor progression.
The record review included 24 patients—four with inoperable primary hilar lung tumors and 20 with hilar tumors that had spread there from other primary sites. The mean radiation dose administered to the esophagus was 27 Gy (11 to 40 Gy) and the mean radiation dose administered to the lung was 45 Gy (30 to 50 Gy).
At one-year, the overall survival was 61% and local control was 71%. The review found that most deaths were attributed to the spread of the patients' cancers. However, there was one death that was attributed to an opening in the mainstem bronchus in a patient who was previously stented.
While no uniform data were collected from patients about quality of life at the time of their treatment, Dr. Collins noted in a news release that the patient records reflect comments made by patients about their symptoms.
“Patients reported improvement with coughing, breathing, and they reported less pain,” Dr. Collins said. “Our study suggests that CyberKnife is a palliative treatment option for hilar lung tumors. We'd like to investigate outcomes with increased radiation doses to see if we can improve local control and overall survival rates. And we'd like to study the impact of administering a drug to make the tumors more sensitive to radiation.
“This is an important first step that gives us a new option to treat potentially morbid hilar tumor. Future studies would likely involve drugs to make the tumor more sensitive to radiation.”
The news release notes that Dr. Collins is a compensated speaker for ACCURAY, the maker of the CyberKnife.