Scottsdale, AZ—A shorter interval from surgery to the start of radiation therapy has been linked to improved survival in patients with head and neck cancers, according to data presented at the 2018 Multidisciplinary Head and Neck Cancers Symposium. Results of a retrospective analysis showed that patients who received radiation within 42 days of surgery had a median overall survival (OS) of 10.5 years versus 8.2 years for those who received radiation 43 to 49 days after surgery. Moreover, when radiation was delayed by ≥50 days postsurgery, the median OS dropped to 6.5 years. The data also demonstrated improved OS for patients who received accelerated versus standard fractionated therapy, the investigators noted.
“This study supports the use of adjuvant radiation therapy starting within 50 days of surgery,” said Jeremy P. Harris, MD, MPhil, Resident Physician, Department of Radiation Oncology, Stanford University, San Francisco, CA, who presented the results.
“The study also supports measures to intensify therapy with accelerated fractionation, especially when delays are unavoidable or patients are at high risk for failure,” he added.
Current National Comprehensive Cancer Network guidelines recommend initiating radiation therapy within 6 weeks of tumor resection, but the benefits of shorter time to radiation therapy, including locoregional control and survival, remain inconclusive.
Dr Harris and colleagues searched the National Cancer Database between 2004 and 2013 to investigate the effect of delayed radiation postsurgery on OS. Patients included in the analysis had squamous-cell carcinoma of the oropharynx, oral cavity, hypopharynx, or larynx. Selected patients also had nonmetastatic stage III/IV tumors, and had definitive surgery followed by adjuvant radiation therapy within 21 to 90 days, with an absorbed dose of 45 to 76 Gy.
Impact of Delayed Radiotherapy
A total of 25,216 patients were identified, 39% of whom received radiation therapy within the recommended 42 days; 19% received radiation 43 to 49 days after surgery; and the remaining 42% received radiation ≥50 days after surgery.
Patients with tonsil cancer were more likely to receive radiation therapy within 42 days of surgery than patients with other head and neck cancers; however, it was far less likely for patients with oral cavity cancer to receive earlier radiation therapy. These patients also were at higher risk, with most receiving ≥60 Gy of absorbed radiation, as well as adjuvant chemotherapy. Although the majority of patients received treatment at academic or community centers, those who received all their care at a single academic facility were less likely to receive radiation therapy within 42 days.
Outcomes showed improved survival with a shorter interval between surgery and the start of radiation therapy. Patients who received radiation therapy within 42 days of surgery had a median OS of 10.5 years versus 8.2 years for patients who received radiation therapy 43 to 49 days after surgery and 6.5 years for patients whose radiotherapy was delayed ≥50 days after surgery.
“When compared to a 42-day delay, a shorter interval between surgery and the start of radiation did not necessarily infer statistically significant benefit to OS, but a prolonged delay resulted in worse survival, which became significant starting at 49 days,” Dr Harris told attendees.
“However, there may be some subsets of patients, including [those with] tonsil cancer, for whom radiation should not be delayed longer than 42 days,” he added.
A secondary analysis also demonstrated improved OS for patients who had accelerated fractionated radiation, defined as ≥5.2 fractions weekly and a median of 5.5 fractions weekly. Patients receiving accelerated fractionated radiation had a median OS of 9.5 years versus 8.3 years with standard fractionation.