A comprehensive model based on temporal dynamics of peripheral T cell repertoire for predicting post-treatment distant metastasis of nasopharyngeal carcinoma.

Many nasopharyngeal carcinoma (NPC) patients develop distant metastases after treatment, leading to poor outcomes. To date, there are no peripheral biomarkers suitable for all NPC patients to predict distant metastasis. Hence, we purposed to develop a noninvasive comprehensive model for predicting post-treatment distant metastasis of all NPC. Since T-cell receptor β chain (TCRB) repertoire has achieved prognostic prediction in many cancers, the clinical characteristics and parameters of TCRB repertoire of 71 cases of peripheral blood samples (pairwise pre-treatment and post-treatment samples from 40 NPC patients who without (nM, n = 21) or with (M, n = 19) post-treatment distant metastasis) were collected. The least absolute shrinkage and selection operator algorithm was used to construct a distant metastasis prediction model. In terms of TCRB repertoire parameters, the diversity of TCRB repertoire was significantly decreased in M group after treatment but not in nM group. Ascending TCRB diversity and higher similarity between pre- and post-treatment samples showed better distant metastasis-free survival (DMFS). The similarity still had robust DMFS prediction in patients with reduced TCRB diversity. More importantly, the 5-factor comprehensive model consisting of basic clinical characteristics and TCRB repertoire indices showed a higher prognostic accuracy than any one individual factor in DMFS predicting. In conclusion, treatment had different effects on the composition of TCRB repertoire in patients without and with post-treatment distant metastasis. The dynamics of TCRB diversity, the similarity of TCRB repertoires, and combinations of these factors with basic clinical characteristics could serve as noninvasive DMFS predictors for all NPC patients.