The Headline: Can imaging of tumor hypoxia guide radiation dose de-escalation for HPV+ oropharyngeal cancer?
The Study: We’ve previously seen results from phase 2 trials evaluating the use of 18F fluoromisonidazole (FMISO) PET to measure tumor hypoxia and guide dose de-escalation. This was an integrated analysis of 3 consecutive phase 2 trials that evaluated this approach. It included 430 patients with T0-3 N1-2c HPV+ oropharyngeal cancer. In addition to standard pretreatment imaging, all patients underwent FMISO PET to measure tumor hypoxia. Those with no baseline hypoxia or who converted to no hypoxia early in treatment based on FMISO PET (75%) received just 30 Gy in 15 fractions with concurrent chemotherapy while those with intra-treatment hypoxia (25%) received the standard 70 Gy. At 5 years, OS was 97% in both arms. There were also no differences between 30 Gy for nonhypoxic and 70 Gy for hypoxic tumors for local failure (2.2% v 1.9%), regional failure (6.2% v 3.9%), or PFS (91% v 89%). However, those who had hypoxia had a significantly higher rate of distant metastasis (7.5% v 1.3%).
TBL: FMISO PET imaging of hypoxia could potentially identify a large proportion of HPV+ oropharyngeal cancer patients who may have excellent outcomes with dose de-escalated radiation. | Lee, ASCO 2026
The Study: We’ve previously seen results from phase 2 trials evaluating the use of 18F fluoromisonidazole (FMISO) PET to measure tumor hypoxia and guide dose de-escalation. This was an integrated analysis of 3 consecutive phase 2 trials that evaluated this approach. It included 430 patients with T0-3 N1-2c HPV+ oropharyngeal cancer. In addition to standard pretreatment imaging, all patients underwent FMISO PET to measure tumor hypoxia. Those with no baseline hypoxia or who converted to no hypoxia early in treatment based on FMISO PET (75%) received just 30 Gy in 15 fractions with concurrent chemotherapy while those with intra-treatment hypoxia (25%) received the standard 70 Gy. At 5 years, OS was 97% in both arms. There were also no differences between 30 Gy for nonhypoxic and 70 Gy for hypoxic tumors for local failure (2.2% v 1.9%), regional failure (6.2% v 3.9%), or PFS (91% v 89%). However, those who had hypoxia had a significantly higher rate of distant metastasis (7.5% v 1.3%).
TBL: FMISO PET imaging of hypoxia could potentially identify a large proportion of HPV+ oropharyngeal cancer patients who may have excellent outcomes with dose de-escalated radiation. | Lee, ASCO 2026