Clinical prognostic factors to guide treatment strategy for HPV­positive oropharyngeal cancer using treatment outcomes of induction chemotherapy: A real­world experience.

ABSTRACT

The role of induction chemotherapy (IC) in locally advanced oropharyngeal cancer (OPC) remains debatable, and suitable candidates for de-escalation treatment in these patients have not been fully identified. Therefore, the present study aimed to identify high-risk candidates for human papillomavirus (HPV)-positive OPC by analyzing patients who underwent IC followed by chemoradiotherapy (CRT) to guide optimal treatment strategies. Patients diagnosed with stage III-IVA OPC and treated with a minimum of two cycles of IC followed by CRT, between 2004 and 2020, were retrospectively reviewed. All the patients were restaged according to the American Joint Committee on Cancer, 8th edition. The overall response rate and survival outcomes associated with clinical factors based on HPV status were analyzed using univariate and multivariate analyses. The present study analyzed 105 patients with a median age of 60 years (range, 40-76 years). Among 105 patients, 40 (38.1%) were HPV-negative and 65 (61.9%) HPV-positive. In all patients, survival outcomes were notably poorer in patients aged ≥60 years (P=0.006) and those who did not achieve complete response post-CRT (P<0.001), irrespective of the HPV status. The median relative dose intensity of IC was ≥80%, indicating adequate treatment, regardless of age. In contrast to patients with HPV-negative OPC, age ≥60 years (P=0.011) and T4 stage (P=0.019) emerged as substantial poor prognostic factors for survival outcomes in patients with HPV-positive OPC. Patients with HPV-positive OPC were categorized into three groups based on the number of clinical factors at diagnosis (such as age and T4 stage). The progression-free and overall survival showed significant stratification across each group as the number of high-risk factors increased despite IC and CRT. The findings indicated that patients with these high-risk factors require a cautious therapeutic strategy even when they are diagnosed with HPV-positive OPC, and the role of combined modality, including IC, will need to be investigated in a randomized trial to be routinely incorporated into clinical practice.