Analysis Confirms SBRT Viability in Older Patients With Lung Cancer

Richard J. Cassidy III, MD

Richard J. Cassidy III, MD

Stereotactic body radiotherapy (SBRT) is safe and effective in patients ≥80 years with early-stage non—small cell lung cancer (NSCLC), results of a multi-center retrospective analysis showed.¹The 2-year estimated local control rate was 84.5% in this elderly population, confirming the survival advantage of this approach over noninterventional strategies for older patients.

This analysis has important implications for the future of treatment for older patients with lung cancer, of which the number is rising, according to Richard J. Cassidy III, MD, who presented the findings during the 2017 Multidisciplinary Thoracic Cancers Symposium.

“As the cancer community ages, and as more patients in their 80s and 90s will present with lung cancer, in addition to the more widespread use of low-dose CT screening, which will increase the number of diagnoses of [patients with] early-stage lung cancer, we need to understand more about which of these patients can safely be treated and is there actually a role for definitive SBRT in this population,” said Cassidy, a resident in radiation oncology at the Winship Cancer Institute, Emory University, Atlanta, Georgia.

“As reported by the US Administration of Aging, based on US Census Bureau data, the percentage of population 85 years and older is projected to increase from 1.5% in 2000 to 2.3% in 2030 and 4.3% in 2050. Similar trends of rising numbers of octogenarians and nonagenarians are also seen in the lung cancer population, many of whom will be in early stages,” said Pranshu Mohindra, MD, who moderated the session during the meeting. “Coexisting medical comorbidities make treatment with curative intent difficult in this population. Hence, highly effective treatment approaches with low toxicity are needed.”

SBRT is the standard of care for patients with early-stage NSCLC who cannot undergo surgery with local control rates of 90% or more,²Cassidy said, and the adoption of SBRT is rising, and thus will be more common even among older patients. “Stereotactic body radiotherapy is an advanced form of localized radiation therapy that uses complex image-guiding techniques to treat tumors with high accuracy. More importantly, treatment can be completed in 3 to 5 sessions over 1 to 1.5 weeks instead of 6 to 7 weeks of daily sessions needed with conventional radiation approaches,” explained Mohindra, assistant professor of radiation oncology, University of Maryland School of Medicine. “As such, SBRT is the current standard for the treatment of medically inoperable patients with early-stage lung cancer, with treatment outcomes that are very comparable to surgery.”

The analysis reviewed the records of patients treated between 2009 and 2015 across 4 centers to find patients who were ≥80 years at diagnosis who were undergoing SBRT. Fifty-eight patients were included in the analysis, with a median age of 84.9 years (range, 80.1-95.2 years) at the time of SBRT. Median follow-up time was 19.9 months.

Cassidy noted that the patient population was a more high-risk group than was often included in previous studies of SBRT in older patients. Among the 58 patients, 51.7% had a prior lung cancer, 12.1% had T3 tumors, and 19% had received prior radiation therapy.

“Our population was relatively high risk compared to some other studies that have looked at elderly patients and may represent potentially ‘a more realistic’ subset of older patients who present to clinic,” Mohindra said.

None of the patients experienced any grade 4/5 toxicities following SBRT. Rates of grade 3 radiation pneumonitis, grade 3 chest wall pain, and grade 3 esophagitis were 6.9%, 3.4%, and 1.7%, respectively. The researchers estimated the 2-year control and survival rates for the group. The 2-year regional control rate was 71.7% (95% CI, 54.1%-83.5%), the metastatic control rate was 85.1% (95% CI, 68.5%-93.4%), the cause-specific survival (CSS) was 72.6% (95% CI, 52.1%-85.4% and the 2-year overall survival (OS) rate was 56.4% (95% CI, 37.6%-71.6%).

The investigators completed recursive-partitioning analysis and reviewed survival rates according to Karnofsky performance status (PS) scores to see which of these patients would potentially derive the most benefit, “because one of the major concerns in this elderly cohort is, are they likely to die from competing medical comorbidities or are they more likely to die of the lung cancer itself,” Cassidy said. “There’s a suggestion that the benefit to treatment is even more pronounced in patients with good functional status,” he stated.

For patients with a PS less than 75, the 2-year CSS was 67.2% (95% CI, 40%-84.2%) and OS was 49.9% (95% CI, 29%-67.6%). For patients with a PS ≥75, the CSS was 96.2% (95% CI, 75.7%-99.4%) and OS was 91.1% (95% CI, 68.4%-97.7%). The median PS among included patients was approximately 75.

“If a patient comes to your clinic who is in their 80s or 90s and can reasonably meet a performance status classified as ‘caring for self, but not necessarily capable of normal activity or work,’ these are patients who you should not withhold treatment on based on their age,” he suggested, with a score of ≥70 indicating the patient was able to care for himself/herself.

References:

1. Cassidy RJ III, Patel PR, Zhang X, et al. Stereotactic body radiotherapy for early-stage non — small cell lung cancer in patients 80 years and older: a multi-center analysis. Presented at: 2017 Multidisciplinary Thoracic Cancers Symposium; March 16-18, 2017; San Francisco, CA.
2. Hayashi S, Tanaka H, Kajiura Y, Ohno Y, Hoshi H. Stereotactic body radiotherapy for very elderly patients (age, greater than or equal to 85 years) with stage I non-small cell lung cancer.Radiat Oncol. 2014;9:138. doi: 10.1186/1748-717X-9-138.