A new survey of radiation oncologists points to a sharp decline in the use of prophylactic cranial irradiation (PCI) for patients with extensive-stage small cell lung cancer (ES-SCLC), indicating a rapid change in standard practice for the disease following publication of a major clinical trial in 2017.
"Small cell lung cancer has a tendency to spread past the lungs to the brain, and brain metastases substantially diminish a patient's quality of life. PCI is preventative radiation therapy given after first-line treatment to eliminate cancerous cells before they become symptomatic metastases," said Olsi Gjyshi, MD, PhD, first author of the study and a radiation oncology resident at the University of Texas MD Anderson Cancer Center.
"Radiation oncologists largely adopted PCI for ES-SCLC following the 2007 publication of a randomised EORTC trial that linked its use to extended overall survival (Slotman et al., NEJM). However, with the recent publication of a Japanese trial showing no survival benefit from PCI compared to MRI surveillance (Takahashi et al., Lancet Oncology), it is important to come to a consensus on how best to treat these patients. Our survey indicates that most providers no longer routinely use PCI for patients with extensive-stage disease that responds to chemotherapy."
To determine the extent of practice changes, researchers surveyed attending radiation oncologists at academic cancer centres across the United States (24% survey response rate).
Anonymous email surveys were collected in September 2018, more than a year after the Takahashi et al. trial was published, and the same year National Comprehensive Cancer Network (NCCN) guidelines were updated to reflect its findings.
All 49 radiation oncologists who specialise in treating thoracic cancers were aware of the Takashashi et al. trial, and two-thirds (67%) had altered their practice in response to its findings.
Specifically, fewer than half of those who offered PCI for ES-SCLC prior to 2017 continued to do so after it was published (78% vs. 38%, p<0.001).
Researchers confirmed the trend of shifting away from PCI in a subsequent nationwide survey of radiation oncologists (N=431).
The trend was consistent across private practices and academic centres.
One-fourth of these physicians reported a decline in PCI referrals by medical oncology for patients with extensive-stage SCLC, and 12 percent also reported fewer referrals for limited-stage SCLC.
"With extensive-stage disease, PCI may best be reserved for patients who are likely to benefit from it, such as those with excellent performance status, younger age (<70 years) and excellent cognitive functions at baseline," said Dr. Gjyshi. "Caution should be used in extrapolating the Takahashi et al. data to patients with limited-stage disease, and further trials may be necessary to address this question."
"Declining PCI use could impact enrolment in future clinical trials, however, so careful consideration should be given to future studies and trials that plan to investigate the role of PCI in this patient population."
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