Investigators who presented findings of a Phase II trial by the Japan Clinical Oncology Group (JCOG) at the 2012 American Society for Radiation Oncology (ASTRO) annual meeting determined that SBRT for early stage, medically inoperable non-small cell lung cancer doubled overall survival rates, as compared to conventional radiation treatment.
“SBRT should be the new standard replacing conventional radiotherapy for patients with early inoperable lung cancer,” said Yasushi Nagata, M.D., lead author of the JCOG research and a radiation oncologist at the Department of Radiation Oncology at Hiroshima University in Hiroshima, Japan. “SBRT is not only effective but is well tolerated and has only mild toxicity, making it a suitable alternative to other therapies. SBRT is also painless and non-invasive, which are big advantages.”
Surgery still holds one advantage: physicians have tissue samples to determine whether the cancer has spread to the lymph nodes. But patients are increasingly interested in less invasive treatment as the evidence for their efficacy becomes more solid, said Chance Matthiesen, M.D., assistant professor of radiation oncology at the University of Oklahoma Health Sciences Center (OUHSC) and lead author of “Stereotactic Body Radiation Therapy (SBRT) for Early Stage Medically Inoperable Non-Small Cell Lung Cancer,” presented at RSNA 2012.
“In this day and age, patients are very smart and read about their options, coming to clinics more educated than ever before,” Dr. Matthiesen said. “They will be asking whether they can have this type of radiation for early-stage lung cancers. If the data can be established, SBRT makes perfect sense because it’s a shorter course of treatment and could be beneficial in terms of convenience and cost.”
SBRT is similar to stereotactic radiosurgery (SRS), but targets areas of the body other than the brain or spine. There is a wide range of manufacturers who have products dedicated to body radiosurgery or who have adapted linear accelerators to accurately deliver radiosurgery to the body.
The devices focus radiation very tightly on the tumor, with minimal radiation exposure to surrounding normal tissue. SBRT can be accomplished in as little as a single treatment, as compared to several weeks with conventional fractionated radiation therapy.
Dr. Nagata’s 2012 study, the companion to a similar study conducted previously among operable lung cancer patients, examined the safety and efficacy of SBRT for 100 inoperable lung cancer patients treated between July 2004 and November 2008.
Median patient age was 78; median tumor size was 21 mm. About half of the patients had adenocarcinomas and 40 percent had squamous cell carcinomas. Patients received an average of 48 Gy in four fractions.
Results showed patients’ overall three-year survival rate was 60 percent. Earlier studies on conventional radiation in inoperable patients showed overall three-year survival rates ranging from 31 to 39 percent. Side effects for SBRT were mild and included dyspnea, hypoxia, pneumonitis chest pain and cough, Dr. Nagata said.
In their research examining clinical outcomes and toxicity of SBRT, Dr. Matthiesen and colleagues retrospectively reviewed 49 patients diagnosed with early stage, medically inoperable non-small cell lung cancer treated with SBRT from 2006 to 2011.
In some cases, tumors were inoperable due to location but most patients had comorbid conditions such as impaired pulmonary function that made them ineligible for surgery. The median patient age in that study was 66.
Just over 73 percent of the group had tumors with a median maximum diameter of 2 cm, and 26.5 percent had a median maximum diameter of 4.3 cm. Approximately 53 percent of patients had squamous cell carcinomas and about 29 percent had adenocarcinomas. The median SBRT treatment was 60 Gy in three to five fractions.
At median follow-up of 16 months, 28 of the 49 patients were alive and 26 had no local recurrence or systemic cancer progression. Of those who had died, only nine patients died of recurrence or progression of lung cancer. Nine patients experienced complications from SBRT including chest wall pain and rib fractures.
“The encouraging thing about SBRT is its low toxicity,” Dr. Matthiesen said. “Acute effects are minimal for the overwhelming majority of patients.” Because SBRT can be accomplished in a much shorter timeframe, this treatment could offer a significant advantage to patients in rural states, he added.
“Sometimes we see patients here who live three hours away who may have a full-time job and a family depending on them,” Dr. Matthiesen said. “A lung cancer diagnosis might mean stopping their life for weeks to get treatment. A week of SBRT is a stressor, but it’s manageable. And it would ease the burden on treatment centers; if you can treat people in five sessions, you can see a lot more patients in a lot less time.”
Access a PowerPoint presentation on Stereotactic Body Radiation Therapy (SBRT) by Yasushi Nagata, M.D., presented at the 2012 ASTRO annual meeting:
Nagata Presentation at ASTRO 2012
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