SAN FRANCISCO—Elderly lung cancer patients with severe co-morbidities can undergo successful treatment using stereotactic body radiation therapy without late toxicities or loss of tumor control, researchers reported here at the American Society for Radiation Oncology Annual Meeting (Abstract 56).
In an update of the RTOG 0236 study, primary tumor recurrence was remarkably low, at seven percent after five years of follow-up in a group of patients whose health was compromised by emphysema, heart disease, or stroke and were not eligible for surgery, said Robert Timmerman, MD, Professor and Vice Chair of the Department of Radiation Oncology at the University of Texas Southwestern Medical Center.
Of the original cohort of 59 frail patients with medically inoperable Stage 1 non-small-cell lung cancer (NSCLC), the 60-month overall survival was 40 percent, and about 26 percent of this patient population achieved disease-free survival at 60 months.
But the key message, he said, was the lack of late complications: “The really exciting news was that there wasn't any significant difference in the toxicity with longer follow-up, which was something many people thought was going to happen,” he said in an ASTRO news conference.
“In fact, toxicities were nearly the same as in the initial report. In that report, 17 patients experienced high-grade toxicity that was mostly pulmonary-related. That was the same in this report.
“The trial included frail patients who had so many serious medical problems that they could not withstand standard treatment for early-stage lung cancer, which is surgery,” Timmerman said. “Patients like this are typically not allowed in clinical trials because their health is so bad, but these were exactly the patients we selected for RTOG 0236.”
The RTOG 0236 results with a follow-up of two to three years were first presented at the 2009 American Society of Clinical Oncology Annual Meeting. “The results at that time were frankly astounding with nearly perfect local control at the treated site,” he said. “There was skepticism, however, and that led to incomplete market penetration at cancer centers due to concern about late toxicity that might occur with longer follow-up or additional recurrences.
“So the results of this trial with a median follow-up of four years with patients having follow-up of over seven years show that indeed the irradiated tumors are very well controlled, with a five-year primary tumor recurrence rate of only seven percent—which is on par with surgery.”
Timmerman predicted that these updated results will re-energize the uptake of stereotactic body radiation therapy for patients who have no other options or who decline surgery. “These results, I think, will change the dynamic of people using stereotactic body radiation therapy. There were many people who wanted to hold back on its use for fear of terrible late side effects. That's probably the biggest message from this long-term results: we do not see those horrible side effects.
“Even though we had only 59 patients in this study, I do believe it will drive practice because it was done through the cooperative group, which has a lot more credibility than single centers. This was practice changing when we first presented this study in 2009, and this report will make it more practice changing,“ he suggested.
‘Insight into Emerging Role of SMRT’
Benjamin Movsas, MD, Chair of Radiation Oncology at Henry Ford Hospital in Detroit, who was the moderator of the news conference, said, “This study provides insight into the emerging role for stereotactic body radiation therapy in patients with lung cancer. At our hospital, we find this technology to be a very promising approach. We are offering very precise accurate treatment, which for the most part is extremely well tolerated.
“I just saw a patient last week who we treated three years ago with stereotactic body radiation therapy for medically inoperable non-small-cell lung cancer when he was 85. He said at the time that he wanted to continue to be able to play golf, and I can tell you that three years later, he's playing golf, he's doing well, and his lung cancer is in control. This is a patient who never would have been able to have surgery based on his other medical conditions.
“We mainly use stereotactic body radiation therapy for the medically inoperable, but there are also patients who for their own reasons decline surgery, so we tell those patients that if they decline surgery this is a secondary alternative.
All these cases are first presented at a multidisciplinary tumor board where we have surgeons, thoracic surgeons, medical oncologists, and radiation oncologists sitting around the table discussing the case before we treat any patients. These decisions are made as part of the multidisciplinary team approach.”
Timmerman said that the survival rate of the patients in RTOG 0236 continues to decline, as would be expected in a cohort of frail patients due to competing causes of death. However, “survival is still very impressive at five years, at 40 percent with a median survival of 48 months.”
A number of recurrences emerged that were not part of the original treatment, including seven patients who had regional failure very late—sometimes after five years after treatment, he said. “There were only two patients in the previous report. Overall, combining local recurrence and regional recurrence, the rate was 38 percent.”
He also said more distant metastases appeared in the updated report: “There were 15 such patients, or 31 percent in our five-year results, while there were only 11 in the previous report. The local-regional failure did increase up to 39 percent after five years, indicating that our staging at the time of diagnosis was incorrect and that there were micrometastases. It did take a long time for many of these to appear, and most of them did appear outside of the treated area.”
In an interview, he noted that some of the recurrences may have been influenced by patients who continued to smoke cigarettes despite being treated for lung cancer: “We strongly encourage our patients to stop smoking, and use the opportunity to raise the stakes for them and give them whatever options for support that we can,” he said. “But honestly, many patients continue to smoke. It's hard to believe, but they do. I don't have specific information on recurrences, but half the patients in the study continued to smoke while on the trial.”