Elimination of postoperative radiation therapy in patients with pathologically negative neck in primary high-risk head and neck squamous cell carcinoma (HNSCC) resulted in excellent disease control rates with no long-term adverse effects on quality of life, according to a study published in Journal of Clinical Oncology.1

Postoperative radiation therapy is associated with toxicity, with reduced volume of radiation resulting in improved quality of life. This phase 2 trial was designed to test if this radiation therapy could be eliminated among patients with high-risk features that mandated postoperative radiation therapy, but who also had a pathologically negative neck after surgical resection and neck dissection. 

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The single-institution study enrolled 72 patients with HNSCC, including cancer of the oral cavity, oropharynx, larynx, hypopharynx, or unknown primary. Despite showing high-risk features mandating postoperative radiation therapy, this therapy was withheld.

At a median follow-up of 53 months, 2 patients had treatment failure of the pathologically negative unirradiated neck; these patients also had local treatment failure, “possibly because of reseeding of lymph nodes from the primary failure.” Both patients had oral cavity primary tumors. 

The unirradiated neck control rate was 97% (95% CI, 93.4%-100.0%). Nine patients had treatment failure at the primary site. Median time to local failure was 16.1 months. 

Five-year rates of local control was 84%, with a progression-free survival rate of 60% and an overall survival rate of 64%. 

Eliminating postoperative radiation therapy did not significantly alter quality of life measurement from baseline to 12 or 24 months. 

“Confirmatory studies completed at the multicenter level with subsite-specific data will help to increase the level of evidence supporting this approach,” the researchers wrote.

Reference

Contreras JA, Spencer C, DeWees T, et al. Eliminating postoperative radiation to the pathologically node-negative neck: long-term results of a prospective phase II study [published online June 27, 2019]. J Clin Oncol. doi: 10.1200/JCO.19.00186