The American Society for Radiation Oncology (ASTRO) has issued new guidelines for head and neck cancer radiation therapy (RT) for the treatment of HPV-associated oropharyngeal squamous cell carcinoma (OPSCC) that provides optimal dosing regimens either alone or after surgery aimed at minimizing doses to areas that may affect a patient’s quality of life.
The new guidelines, published in Practical Radiation Oncology, are the result of an ASTRO task force convened to address five key questions for the use of RT to treat HPV-associated OPSCC which included:
- Indications for definitive and postoperative RT and chemoradiation
- Dose-fractionation regimens and treatment volumes
- Preferred RT techniques and normal tissue considerations
- Post-treatment management decisions
The task force did not address indications for primary surgery versus RT and the recommendations were based on a systematic literature review.
The analysis by the task force produced guidelines that recommend cisplatin for patients receiving definitive RT with T3-4 disease and/or one node >3 cm, or multiple nodes. For similar patients who are ineligible for cisplatin, the guidelines conditionally advise concurrent cetuximab, carboplatin/5-fluorouracil, or taxane-based systemic therapy.
For postoperative treatment, RT with concurrent cisplatin is recommended for positive surgical margins or extranodal extension. Postoperative RT alone is recommended for pT3-4 disease, more than two nodes, or a single node larger than three centimeters. Observation is conditionally recommended for pT1-2 disease and a single node that is less than three centimeters without other risk factors.
Further recommendations on radiation dosing levels for HPV-associated head and neck cancer are also provided as well as recommendations for modulating the dosage of all patients receiving RT to protect at-risk organs such as salivary and swallowing structures.
“One of the important decisions in treating any patient with OPSCC is whether to use concurrent systemic therapy and, if so, which regimen,” the members of the task force wrote. “For patients receiving definitive or postoperative RT with concurrent systemic therapy, the long-established standard of cisplatin remains the evidence-based recommendation, but additional trials are needed for cisplatin-ineligible patients.”
The authors acknowledge that for patients with early-stage HPV-positive OPSCC treated with definitive RT, there is debate over which patients benefit from systemic therapy noting that “in the absence of pending clinical trials, such decisions will likely remain highly individualized.”
They also walk a fine line regarding RT dose reduction strategies. Hopes are that a current randomized clinical trial that is testing lowering the postoperative RT dose and omitting cisplatin chemotherapy for patients with traditional indications of positive margins and/or ENE will provide a clearer picture of this treatment strategy.
In total, the task force recommendations used data from 186 studies published between January 2000 through May 24, 2023, and included randomized controlled trials (RCTs), individual patient data meta-analyses, retrospective studies, and dosimetric/contouring studies. The relevant patient population for these studies were people older than 18 and the task force also required populations for prospective studies to include more than 50 patients, and retrospective studies to include more than 100 participants.
