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SBRT offers treatment option for elderly patients with lung cancer
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Stereotactic body radiotherapy was safe and effective for elderly patients with early-stage lung cancer, according to results of a retrospective analysis presented at the Multidisciplinary Thoracic Cancers Symposium.
“As the cancer community ages and 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 early-stage lung cancer patients — we need to understand more about which of these patients can safely be treated, and if there is actually a role for definitive [stereotactic body radiation therapy] in this population,” Richard J. Cassidy III, MD, resident in radiation oncology at Emory University’s Winship Cancer Institute, said during a press conference.
Stereotactic body radiation therapy (SBRT) — an advanced form of therapy that transfers highly targeted, escalated radiation in minimal sessions — is the standard of care for patients with early-stage lung cancer who are unable to undergo surgical resection.
Multiple randomized studies have shown local control rates of over 90% in patients treated with SBRT. However, the age of patients in these studies varied, and very few patients aged 80 and older were included in these types of trials, Cassidy said.
Cassidy and colleagues reviewed records of 242 consecutive patients treated with SBRT at one of four academic centers between 2010 and 2015. The researchers measured multiple variables including age, prior cancer diagnosis, prior thoracic radiation, tumor histology, radiation delivery method, among others.
“The purpose ... was to investigate the safety, efficacy and survival of patients 80 years and older treated with [SBRT],” Cassidy said.
Fifty-eight patients (median age, 84.9 years) with complete medical records were included in the final analysis. These patients had a median Karnofsky performance status of 70 and received a median dose per fraction of 10 Gy with a median of five fractions.
In total, 39.7% of patients had adenocarcinoma, 29.3% had squamous cell carcinoma and 31% of patients were not biopsied.
Disease control endpoints following 2 years of definitive SBRT were favorable, Cassidy said. The local control rate was 84.5%, regional control rate was 71.7%, distant control rate was just over 85%, cancer-specific survival was just under 73% and OS was just over 55%.
Patients who were not active smokers had higher cancer-specific survival (HR = 0.14; P = .03). Patients with lower cancer-specific survival tended to be older (HR = 1.19; P = .04) or previously diagnosed with lung cancer (HR = 7.75; P = .01).
Local failure was more common among patients with adenocarcinoma w (HR = 6.36; P = .01) and less likely among patients with T1 tumors (HR = 0.2; P < .01).
Higher Karnofsky scores were associated with lower rates of both local failure (HR = 0.92; P < .01) and regional failure (HR = 0.94; P < .01), as well as better OS (HR = 0.91; P < .01). This metric may be considered when offering SBRT to elderly patients — with best outcomes observed with a median Karnofsky score of 75 or higher — because it is associated with improved outcomes, Cassidy said.
At 3 years, the local recurrence rate was 39.5%, regional recurrence rate was 43.9%, cancer-specific survival was 83.3% and OS was 69.2%.
The rate of radiation pneumonitis of any grade was 34.5%.
One of the most important things investigated in this population was the safety of treatment, Cassidy said.
“We found there were no grade 4 or 5 toxicities, and the rates of grade 3 or higher toxicity of radiation pneumonitis was quite reasonable at just under 7%,” Cassidy said. “There were few grade 3 chest pain toxicities and one grade 3 esophagitis toxicity.”
Because this patient population was categorized as high-risk — more than 50% of these patients had prior lung cancer, almost 20% had prior thoracic radiation and more than 12% had T3 tumors — the results may represent a more “realistic subset of patients” to present to clinic,” Cassidy said.
“If a patient comes to your clinic who is in their 80s and 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 you should not withhold treatment on just because of their age,” Cassidy said. – by Melinda Stevens
Reference:
Cassidy III RJ, et al. Abstract 111. Presented at: Multidisciplinary Thoracic Cancers Symposium; March 16-18, 2017; San Francisco.
Disclosures: The researchers report no relevant financial disclosures.
Perspective
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Pranshu Mohindra, MD, MBBS, DABR®
As reported by the U.S. Administration of Aging based on the U.S. Census Bureau data, the national population of individuals aged 85 years and older is predicted to increase from 1.5% in 2000 to 2.3% in 2030 and 4.3% in 2050. Similar trends of rising numbers of octo- and nonagenarians are also seen in the lung cancer population, many of whom will be diagnosed in early stages. Coexisting medical comorbidities make treatment with curative intent difficult in this population, and highly effective treatment approaches with low toxicity are needed. Stereotactic body radiation therapy, or SBRT, is an advanced form of localized radiation therapy that uses complex image guidance techniques to treat tumors at high doses with high accuracy. More importantly, treatment can be completed in three to five sessions or 1 to 1.5 weeks, instead of 6 to 7 weeks of daily sessions needed with conventional radiation approaches. As such, SBRT is the standard for treatment of medically inoperable patients with early-stage lung cancer with treatment outcomes that are very comparable to surgery.
Cassidy and colleagues’ study describes the safety and tolerability of SBRT, even in the elderly population of those aged 80 years or older. No serious toxicities or deaths were reported in their experience. An estimated 85% of patients continued to have disease control at the original tumor site.
Although other institutions have previously reported similar experiences, this study provides 2-year outcomes demonstrating the durability of treatment effect. With an increasing number of published reports of safety and efficacy — combined with increasing and widespread ability of SBRT capabilities — practitioners should strongly consider SBRT as a treatment option for elderly patients unfit for surgery. This should be chosen in comparison to pursuing noninterventional strategies.
Reference:
Administration on Aging. U.S. Department of Health and Human Services. Available at: aoa.acl.gov/Aging_Statistics/index.aspx. Accessed on April 13, 2017.
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