An Optimal Assessment Schedule after Definitive Locoregional Treatment in Locally Advanced Head and Neck Cancer Using Parametric Modeling

Abstract

<h3>Purpose/Objective(s)</h3> Surveillance plan after definitive treatment in head and neck cancer (HNC) is determined arbitrarily in daily clinical practice. This study aims to establish an optimal assessment schedule model in locally advanced HNC using a parametric model of standardized event-free survival (EFS) curves. <h3>Materials/Methods</h3> A total of 673 patients with locally advanced HNC (227 nasopharynx (NPC), 237 HPV-positive oropharynx (HPV+ OPC), 47 HPV-negative oropharynx (HPV- OPC), 65 hypopharynx (HPC), and 97 larynx cancer (LC)) who completed definitive locoregional treatment were retrospectively analyzed. EFS was defined as the period from the end of treatment to the date of any event (tumor recurrences or secondary malignancies). EFS curves were estimated using the piecewise exponential model and divided into three phases of regular follow-up. The criterion of a 5% event rate among the remaining patients was used to determine the optimal follow-up time point and interval. <h3>Results</h3> With a median follow-up of 57.8 months (range, 6.4–158.1 months), the event rates of NPC, HPV+ OPC, HPV- OPC, HPC, and LC were 18.9%, 14.8%, 36.2%, 44.6%, and 30.9%, respectively. Using parametric modeling, the optimal follow-up intervals for HPC/LC/NPC were every 2.1/3.2/6.1 months until 16.5 months after treatment, every 3.7/5.6/10.8 months from 16.5 to 25 months, every 9.1/13.8/26.5 months from 25 to 99 months, and open follow-up thereafter. For HPV- OPC, surveillance every 2.7 months until 16.5 months after treatment, every 4.8 months from 16.5 to 25 months, and every 11.8 months from 25 to 99 months were recommended. In contrast, for HPV+OPC, optimal intervals were every 7.7 months until 16.5 months after treatment, every 13.7 months from 16.5 to 25 months, every 33.7 months from 25 to 99 months. The recommended number of follow-up visits was 5, 4, 12, 15, and 10 times for NPC, HPV+ OPC, HPV- OPC, HPC, and LC, respectively. <h3>Conclusion</h3> The optimal assessment schedule for HNC stratified by primary subsites and HPV status was reasonably established using parametric modeling of EFS curves. Due to the limited healthcare resource and increasing number of HNC patients, this evidence-based assessment model will be worthwhile.