Outcomes Following Extreme Elective Nodal De-Escalation in HNSCC Treated With Curative Intent: A Community Program Experience

To evaluate elective nodal recurrence rates in HNSCC patients treated with extreme dose de-escalation to 30 or 40 Gy followed by a sequential boost to gross disease or high-risk sites.

Between May 2017 and May 2025, patients diagnosed with SCC of the oropharynx, larynx, or hypopharynx were treated with definitive chemoradiotherapy or surgery followed by adjuvant (chemo)radiotherapy. Elective nodal volumes (ENV) defined as any uninvolved adjacent, distant ipsilateral or contralateral anatomic nodal level were treated to either 30 or 40 Gy, followed by a sequential boost to the PTVp/PTVn+ or high-risk surgical bed (PTVp+ PTVn+). A subset of 6 patients received 24-36 Gy (1.5-1.8 Gy BID) based on the Mayo-DART regimen. Assignment to 40 Gy versus 30 Gy reflected the radiation oncologist preference based on emerging trial evidence. All cases were reviewed prospectively in a head and neck multidisciplinary conference, and treatment planning required diagnostic FDG PET-CT fused to the planning CT. Concurrent systemic therapy was administered in 99% of patients. The primary endpoint was regional failure rate within the de-escalated ENV. Secondary endpoints included 1- and 2-year locoregional control (LRC), progression-free survival (PFS), distant metastasis-free survival (DMFS), and failure patterns.

The analysis included 102 patients of whom the majority 81.4% received definitive chemoradiotherapy, 17.6% underwent surgery with adjuvant chemoradiotherapy, and 1% received surgery with adjuvant radiation alone. The elective nodal volume was treated to 40 Gy at 2 Gy per fraction in 81 patients and to 30 Gy at 2 Gy per fraction in 15 patients; the remaining 6 adjuvant patients received 24-36 Gy at 1.5-1.8 Gy twice daily per the Mayo-DART regimen. With a median follow-up of 26.4 months, no elective nodal failures were observed in either dose cohort. The 1- and 2-year LRC rates were 93.5%. The 1- and 2-year progression-free survival (PFS) rates were 88.6% and 87.3%, respectively, while distant metastasis-free survival (DMFS) rates were 95.0% and 95.0%, respectively. In total, 13 recurrences were recorded comprising 7 locoregional and 6 distant failures.

This represents the largest report demonstrating the efficacy of extreme dose de-escalation to ENV's for HNSCC within an NCI designated community cancer program. Reduced doses to the ENV ranging from 40 Gy to as low as 30 Gy were associated with exceptionally low failure rates regardless of treatment approach, stage, or HPV, and validate similar findings previously reported from larger academic centers. Importantly, 99% of patients received concurrent systemic therapy, and these results should not be extrapolated to radiotherapy alone.