Comorbidity in head and neck cancer: Is it associated with therapeutic delay, post-treatment mortality and survival in a population-based study?

OBJECTIVES

This study aims to investigate the relationship between comorbidities and therapeutic delay, post-treatment mortality, overall and relative survival in patients diagnosed with squamous cell carcinoma of the head and neck (HNSCC).

PATIENTS AND METHODS

9245 patients with a single HNSCC diagnosed between 2009 and 2014 were identified in the Belgian Cancer Registry. The Charlson Comorbidity Index (CCI) was calculated for 8812 patients (95.3%), distinguishing patients having none (0), mild (1-2), moderate (3-4) or severe comorbidity (>4). The relationship between CCI and therapeutic delay was evaluated using the Spearman correlation. Post-treatment mortality was modelled with logistic regression, using death within 30 days as the event. The association between comorbidity and survival was assessed using Cox proportional hazard models.

RESULTS

Among 8812 patients with a known CCI, 39.2% had at least one comorbidity. Therapeutic delay increased from 31 to 36 days when the CCI worsened from 0 to 4 (rho = 0.087). After case-mix adjustment, higher baseline comorbidity was associated with increased post-surgery mortality (mild, OR 3.52 [95% CI 1.91-6.49]; severe, OR 18.71 [95% CI 6.85-51.12]) and post-radiotherapy mortality (mild, OR 2.23 [95% CI 1.56-3.19]; severe, OR 9.33 [95% CI 4.83-18.01]) and with reduced overall survival (mild, HR 1.39, [95% CI 1.31-1.48]; severe, HR 2.41 [95% CI 2.00-2.90]). That was also the case for relative survival in unadjusted analyses (mild, EHR 1.77 [95% CI 1.64-1.92]; severe, EHR = 4.15 [95% CI 3.43-5.02]).

CONCLUSION

Comorbidity is significantly related to therapeutic delay, post-treatment mortality, 5-year overall and relative survival in HNSCC patients. Therapeutic decision support tools should optimally integrate comorbidity.