895P - Cost effectiveness of stereotactic ablative radiotherapy (SABR) alone in comparison with systemic treatment and SABR in oligometastatic head and neck cancer in the GORTEC 2014-04 OMET randomized phase II study

Background

Stereotactic Ablative Radiotherapy (SABR) is increasingly used in genuine oligometastases (oMets) to defer systemic treatments. The GORTEC 2014-04 OMET randomized phase II study assessed survival without definitive quality of life (QoL) deterioration after omitting upfront systemic treatments in oMets in HNSCC pts by SABR alone. Inclusion criteria were PS 0-2, life expectancy ≥6mo, controlled primary, 1-3 PET-confirmed mets, cumulated tumor ≤7cm. The 2014 standard of care (SOC) was Extreme. 69 pts in 11 centers, 2016-2022, male 81.2%, 62.7 yo, PS1-2 52.3% & comorbidities 81.7%, HPV 23.2%, had lung-only 82.6%, isolated 58.0% oMets. 1y-OS woQoL loss was similar in both arms (∼ 13 mo). W median follow-up 53.7mo, median OS was not reached, & similar in both arms. All grade (G) toxicity rates were 29.4% (G3-4 5.9%) w SABR-alone & 94.3% (G3-4 60.0%) w chemo-SABR. Omission of upfront chemo in oMets HNSCC pts led to lower severe toxicity rates, similar survival & QoL deterioration rates & defered systemic treatments. We evaluated cost-effectiveness of SABR-alone vs chemo-SABR & time until definitive deterioration.

Methods

QALYs were equivalent; cost minimisation analysis was done from the French Public health system perspective. Direct medical costs were collected from randomization until 12months or death: hospital stays for SABR/anticancer drugs, SAE management, imaging, biology & transports; without annual discount rate. Robustness was assessed by deterministic one-way sensitivity analyses on cost drivers.

Results

EQ-5D-3L loss at baseline vs month 12 were 0.84 vs 0.87 w SABR-alone & 0.85 vs 0.57 w chemo-SABR Significant difference was observed on total cost: mean €8,498 ± 3,599 (median: 7,330 [4,509-19,884] for SABR, €48,034 ± 58,228 (28,881 [5,826-259,643]) for chemo-SABR (p< 10^-4). Sensitivity analyses showed results' robustness w cost saving of €35,000-€40,000 / pt w SABR-alone.

Conclusions

Clinical & medicoeconomic management of oMets suggest benefits from oMet-directed ablative strategies. Cost-minimization analysis suggests that SABR-alone is the least costly option by a factor of 5.

Clinical trial identification

NCT03070366.

Editorial acknowledgement

Legal entity responsible for the study

GORTEC.

Funding

GORTEC.

Disclosure

All authors have declared no conflicts of interest.