George Rodrigues, MD, PhD
Radiation therapy can be effectively delivered in more focused, intensive, and shorter-course treatment regimens that offer patients at least equivalent—and in some cases superior—outcomes in several tumor types, thus helping to mitigate challenging adverse effects of standard approaches, according to research presented at the 2016 ASTRO Annual Meeting.
Four studies in which innovative strategies using accelerated versus conventional treatment approaches in patients with brain metastases, lung cancer, and prostate cancer were highlighted during the conference, which took place September 25-28 in Boston.
“All 4 presentations detail important randomized controlled data on the topic of hypofractionated radiation treatment that were carried out in several cancer centers,” said George Rodrigues, MD, PhD, who served as moderator during a press briefing where the research was discussed.
“Research about hypofractionated radiation is important to our specialty, our patients, and society in order to provide both convenient and cost-effective care without sacrificing treatment efficacy and while improving toxicity profiles,” said Rodrigues, who is a clinician scientist and radiation oncologist at the Lawson Health Research Institute and London Health Sciences Centre in Canada.
In the first study,1
researchers at the Mayo Clinic and other sites presented findings that compared stereotactic radiosurgery (SRS) with whole-brain radiotherapy (WBRT) in patients with resected metastatic brain cancer. “In this multi-institutional trial, Mayo Clinic researchers found comparable survival rates, better quality of life, and less cognitive decline following postoperative SRS compared with WBRT,” said Rodrigues.
Similarly, Anita Mahajan, MD, and colleagues found that SRS decreased the rate of local occurrence compared with observation alone following resection in patients with brain metastasis.2
“There was no difference in distant metastasis or overall survival (OS) between the 2 groups,” said Mahajan, a professor in the Department of Radiation Oncology at The University of Texas MD Anderson Cancer Center.
In the thoracic cancer arena, Puneeth Iyengar, MD, PhD, of the University of Texas Southwestern, Dallas, found that the use of accelerated, hypofractionated radiation therapy can cut treatment time in half compared with conventional therapy with similar efficacy for patients with stage II/III non–small cell lung cancer (NSCLC) who cannot undergo surgery or radiation plus chemotherapy.3
In the fourth study, Anders Widmark, MD, PhD, of Umeå University in Sweden, presented findings showing that men with intermediate-risk prostate cancer are able to undergo “extremely” hypofractionated radiation therapy without experiencing more adverse events than they would have with conventional therapy.4
WBRT Versus SRS in Brain Metastases
The use of postoperative SRS for patients with resected brain metastases should be considered standard of care because of its equivalent survival, better preservation of function and quality of life, and less toxicity compared with WBRT, said Paul D. Brown, MD, a radiation oncologist at the Mayo Clinic in Minnesota.
Currently, WBRT after resection of brain metastasis to improve local control is the standard of care, but it is fraught with difficult adverse effects including hair loss, fatigue, skin redness, and cognitive impacts, and has shown no survival benefit.
With SRS, surgeons are able to deliver escalated doses of radiation targeted to the tumor while limiting the impact on surrounding tissue. Among clinicians, there has been a growing use of delivering SRS to the surgical cavity to reduce cognitive toxicity but, to date, no level I efficacy data for postoperative SRS have been available.
Brown and colleagues investigated 194 patients with resected brain metastases who were stratified by the number of preoperative brain metastases (1 vs 2-4), histology (lung vs radioresistant vs other), and resection cavity diameter (≤3 cm vs >3 cm). Most of the patients (77%) had a single brain metastasis, with lung cancer as the primary tumor type (59%).
After stratification, patients were randomized to receive either WBRT or SRS. Primary endpoints of the trial included cognitive deterioration–free survival and OS.
The researchers observed no difference in OS between the SRS arm (11.8 months) and the WBRT arm (11.5 months), but noted worse cognitive function over time associated with WBRT (2.8 months) compared with SRS (3.3 months). (Figure
In addition, surgical bed control was similar, although over the long term it appeared better with WBRT compared with SRS (7.7 vs 7.5 months, respectively).