853O - OMITting frontline chemotherapy in head and neck cancer (HNSCC) patients with 1-3 oligometastases using stereotactic ablative radiotherapy (SABR), the GORTEC 2014-04 “OMET” randomized phase II trial

Background

Most trials in metastatic HNSCC compare systemic therapies; HNSCC were underrepresented in the few multihistology SABR trials; none has assessed SABR-alone vs chemo-SABR in often frail/heavily-pretreated HNSCC patients. The GORTEC 2014-04 phase IIR study assesses impact on survival without definitive quality of life (1yOS-QoL) deterioration of omitting frontline chemotherapy in oligometastatic HNSCC patients (pts) by using SABR alone.

Methods

SABR-alone (experimental arm) or chemo (SOC Extreme)-SABR to 1-3 metastases (mets) was evaluated using survival, PFS, definitive QoL deterioration (global, 10 points), toxicities (highest-grade/patient), QoL dimensions. Salvage treatments were left to physician’s appreciation (repeat SABR allowed).

Results

69 pts treated at 11 centers in 2016-22, male 81.2%, mean age 62.7, had lung-only mets in 57 (82.6%), isolated mets in 40 (58.0%). Median baseline global QoL score was 66.7 (Q1-Q3 50.0-83.3). Of 57 pts eligible for 1yOS-QoL (QoL & follow-up missing in 10 & 2 pts/69), it was equivalent in both arms, with better Kaplan-Meier estimates of physical functioning & cough score deterioration-free survival with SABR-alone. In ITT analysis (69 pts), 1-year & median survival were 63.4 (95%CI 47.6-84.5), 47.2 with SABR-alone vs 61.7 (CI 46.2-82.4) & 42.3 months (m) with chemo-SABR. Median follow-up was 55.3m (CI 42.5-72.1) & 45.4m (CI 36.7-69.1) in the SABR-alone & chemo-SABR arms. One-year PFS rate were 38.2% with SABR-alone & 53.3% with chemo-SABR (1^st CT done earlier in SABR-alone arm, p NS). Following relapse (N=58, 48 pts), 16 (10 in chemo-SABR, 6 SABR-alone arms) new out-of-field lesions and 1 in-field (in SABR-arm) mets were retreated with SABR-alone (17/58, 29.3%). Rates of all grade toxicities were 43/69 (62.3%): 10/34 (29.4%) with SABR-alone & 33/35 (94.3%) with chemo-SABR. Rates of severe G3-4 toxicities were 24/69 (34.8%): 2/34 (5.9%) with SABR-alone & 21/35 (60.0%) with chemo-SABR.

Conclusions

Omission of frontline chemotherapy in oligometastatic HNSCC pts led to lower severe toxicity rates, similar rates of survival & 1yOS without QoL deterioration. Medicoeconomic results will be provided.

Clinical trial identification

NCT03070366.

Editorial acknowledgement

Legal entity responsible for the study

GORTEC - Pr Bourhis.

Funding

GORTEC.

Disclosure

All authors have declared no conflicts of interest.