KEY TAKEAWAYS
- The SAVER phase II trial aimed to assess if reducing contralateral neck radiation volumes in p16+OPC patients improves toxicity without compromising regional control.
- The primary endpoint was an elective out-of-field contralateral nodal failure.
- The results demonstrated safe selective avoidance in p16+OPC, maintaining regional control with favorable organ doses.
The majority of patients with p16-positive head and neck cancer, particularly in the oropharynx (p16+OPC), commonly undergo contralateral elective nodal radiation therapy. While this improves regional control, it often results in heightened acute and long-term toxicity.
Jason K. Molitorisa and the team spearheaded a study by hypothesizing that implementing a validated volume reduction strategy in the contralateral neck could effectively mitigate toxicity in patients with p16+OPC undergoing definitive or adjuvant radiation therapy.
The study enrolled newly diagnosed patients with p16-positive oropharyngeal cancer (p16+OPC) lacking contralateral nodal involvement, undergoing primary proton or photon-based (chemo)radiation or adjuvant (chemo)radiation post Transoral Robotic Surgery (TORS).
The reduced contralateral nodal volume encompassed level II and III regions, targeting high-risk areas for contralateral nodal disease. The primary endpoint focused on elective out-of-field contralateral nodal failure. Dosimetric comparisons between standard versus reduced elective nodal volumes were conducted. Acute toxicity data were gathered utilizing CTCAE v4.0.
About 52 patients were enrolled, with 36 (69.2%) undergoing definitive (chemo)radiation and 16 (30.8%) receiving adjuvant radiation after TORS, including 5 (31.2%) with concurrent platinum-based chemotherapy. Proton therapy was utilized in 38 (73.1%) patients. No contralateral nodal failures occurred over a median follow-up of 15 months (range 1-24 months).
Among the first 20 patients, dosimetric analysis comparing reduced contralateral elective nodal volumes to consensus volumes revealed decreased mean dose (18.5 Gy to 14.1 Gy [P<0.05]) and V30 Gy (21.3% to 11.6% [P<0.01]) of the contralateral parotid dose. These differences were significant regardless of radiation modality or technology. Acute grade 3 toxicity was observed in 13 (25%) patients, with 6 (11.5%) requiring a PEG tube during treatment. No grade 4-5 acute toxicities occurred, and by 6 months follow-up, no patients retained a PEG tube.
The study concluded that selectively avoiding nodal volumes in the N0 contralateral neck of patients with p16-positive oropharynx cancer can be safely achieved while maintaining excellent regional control. Favorable outcomes were observed regarding dose to contralateral organs at risk and toxicity profiles. Continued follow-up is underway to reinforce the efficacy of this de-intensification strategy.
Research was funded by University of Maryland, Baltimore.
Source: https://astro.confex.com/astro/hncs2024/meetingapp.cgi/Paper/59703
Clinical Trial: https://clinicaltrials.gov/study/NCT04609280
J. K. Molitoris, M. E. Witek, et al. (2024) ‘’ Early outcomes for a single-arm phase I/II trial of Selective Avoidance of nodal VolumEs at minimal Risk (SAVER) in the contralateral N0 neck of patients with p16-positive oropharynx cancer.’’ Presented at MHNCS 2024. (Abstract 17).
