Tumour and adipose tissue uptake on F-Fluorodeoxyglucose (F-FDG) positron emission tomography/computed tomography (PET/CT) predict immunotherapy response in recurrent or metastatic nasopharyngeal carcinoma.

AIM

This study evaluated the prognostic value of F-Fluorodeoxyglucose (F-FDG) uptake in tumour and adipose tissue in recurrent or metastatic (R/M) nasopharyngeal carcinoma (NPC) patients treated with immunotherapy.

MATERIALS AND METHODS

We retrospectively included 120 patients with R/M NPC treated with PD-1 inhibitors. Maximum standardised uptake value (SUV), metabolic tumour volume (MTV), and total lesion glycolysis (TLG) of all malignant lesions were recorded. Additionally, SUV and SUV were measured for subcutaneous and visceral adipose tissue (SAT and VAT). The study classified patients who, within six months of immunotherapy, either experienced tumour progression, died, or changed treatment regimens as the nonclinical benefit (non-CB) group, and others as the CB group. The primary endpoints were progression-free survival (PFS) and overall survival (OS).

RESULTS

The CB group had significantly lower primary tumour MTV (PT-MTV) (median, 15.8 vs 48.1, P=0.006), PT-TLG (median, 88.7 vs 275.6, P=0.008) and SUV-VAT (median, 0.63 vs 0.77, P=0.047) than non-CB group. More T4 stages (71.4% vs. 41.3%) and lung metastases (42.9% vs 21.7%) were observed in the non-CB group compared to the CB group. Multivariate analysis indicated lung metastases (P=0.002, hazard ratio [HR] = 2.204, 95% confidence interval [CI]: 1.323-3.669) and higher primary tumour burden (P<0.001, HR= 3.379, 95% CI: 1.768-6.460) as independent PFS predictors. Only higher primary tumour burden (P=0.027, HR=2.513, 95% CI: 1.108-5.698) was an independent OS predictor.

CONCLUSION

Our study indicates that higher primary tumour burden is associated with poor prognosis for NPC patients undergoing immunotherapy. SUV-VAT may be a promising predictor for immunotherapy response.