Validity of a single-item indicator of treatment side effect bother in patients with head and neck cancer

Purpose: Patients with head/neck squamous cell carcinomas (HNSCC) experience significant tumor- and treatment-related side effects. No efficient summary measure capturing the totality of side effect burden currently exists. We examined associations between a single patient-reported outcome (PRO) item evaluating side effect bother (FACT GP5, "I am bothered by side effects of treatment") with overall side effects in HNSCC.

Methods: We performed a retrospective secondary analysis of development of the Functional Assessment of Cancer Therapy (FACT) Head/Neck Symptom Index (FHNSI-10), which included completing FACT-HN (including Head/Neck Cancer Subscale (HNCS) and Trial Outcome Index (TOI)) and the pain intensity numeric rating scale (NRS). We calculated Spearman's correlations between GP5 and these measures of patient-reported global health, head/neck side effects, and pain intensity NRS. A correlation of > 0.4 was considered sufficient evidence of association.

Results: Ninety-seven patients completed baseline and 85 completed 3-month follow-up surveys. GP5 was highly correlated with FACT-HN total score (baseline r = 0.66, 3 months r = 0.67) and FHNSI-10 (baseline r = 0.63, 3 months r = 0.65). GP5 correlated with multiple FACT-HN subscales including FACT-G, physical well-being, functional well-being, HNCS, and TOI (range baseline r = 0.53-0.77, range 3 months r = 0.49-0.77). Worsening GP5 score was associated with worsening overall HNCS (p = 0.002), worsening FHNSI-10 score (p < 0.001), and worsening mean pain intensity (p < 0.001).

Conclusion: GP5 exhibited validity within HNSCC, exhibiting substantial correlations with a number of HNSCC-related PRO measures including FACT-HN and FHNSI-10. Worsening GP5 was associated with worsening HNCS, FHNSI summary score, and pain intensity. GP5 has promise as a summary indicator of symptom and side effect bother in HNSCC.