Quality of life, function, and symptom trajectory patterns following salivary gland cancer treatment: a 5-year prospective cohort study

Longitudinal patterns of patient-reported quality of life (QoL) remain poorly understood in patients with salivary gland cancer (SGC). This study aimed to identify distinct trajectories of QoL over 5 years following SGC treatment and to evaluate the baseline characteristics associated with adverse recovery patterns.

This prospective cohort study was conducted at a tertiary cancer center from 2016. Patients with histologically confirmed SGC were enrolled prior to treatment and followed longitudinally for up to 5 years. Repeated QoL assessments were conducted using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 and Head and Neck Cancer-Specific Module 35 questionnaires at standardized intervals. The primary outcome was the global QoL trajectory over 5 years, modeled using group-based trajectory analysis.

Among 252 participants, three QoL trajectories were identified: Stable Good (n = 132, 52.4%), Declining (n = 41, 16.2%), and Delayed Recovery (n = 79, 31.3%). Female sex, older age, worse baseline pain score, and recurrence were significantly associated with an unstable trajectory of QoL. Interestingly, treatment intensity was not a significant factor for QoL. The Delayed Recovery group showed improvements in nutritional status and pain burden. The Declining group experienced deterioration in role, cognitive, and social functioning, along with increased fatigue, pain, and head-and-neck-specific symptoms.

Long-term QoL changes following SGC treatment are heterogeneous, with nearly half of the patients experiencing either persistent or delayed impairment. Trajectory-based classifications may support the early identification of vulnerable survivors and inform risk-stratified supportive care strategies targeting pain, nutrition, and emotional function.