Poor Radiotherapy Compliance Predicts Persistent Regional Disease in Advanced Head/Neck Cancer

Objective: To determine if poor compliance to chemoradiation results in an increased rate of persistent neck disease. Study Design: Retrospective, cohort study in an urban, tertiary-care medical center. Methods: The study included patients with N+ stage III/IV squamous cell carcinoma of the upper aerodigestive tract treated with curative-intent chemoradiation, who underwent subsequent planned neck dissection. Main outcome measure was persistent regional disease evidenced by identifiable carcinoma in neck dissection specimens. Variables including age, gender, race, primary site, initial T, N staging, imaging results, and treatment compliance were assessed and correlated to positive neck dissection pathology. Results: Of 40 patients, 18 (45%) had persistent carcinoma in neck dissection specimens while 22 (55%) demonstrated complete response in the neck. There were 14 patients (35%) who were poorly compliant to radiotherapy (>= 14 days treatment interruption) and the remaining 26 patients (65%) were considered compliant (<14 missed days). Only 23% of compliant patients had positive pathology while 79% of noncompliant patients had positive pathology (hazard ratio: 9.9). Noncompliance was the only variable that had a statistically significant correlation to positive pathology results (P = .002). Multivariate logistic regression showed all other variables to be insignificant in predicting pathology. Conclusions: This study found that poorly compliant patients are at significantly higher risk of persistent neck disease. Poor compliance may help identify patients who will most benefit from neck dissection after chemoradiation. This variable was more predictive than pretreatment variables and posttreatment CT scan. Further studies investigating patterns of failure after chemoradiotherapy in the poorly compliant patient population are warranted.