The specific agents given could not be ascertained, she acknowledged. “Unfortunately, the NCDB does not give us data in regard to the type of chemotherapy, and they only started collecting cetuximab data in 2013.”
With a median follow-up of 19 months, the unadjusted 5-year overall survival rate was 15.2% with radiation therapy alone and 30.3% with concurrent chemoradiation (hazard ratio, 0.59; P less than .001). Benefit fell only slightly after multivariate adjustment (HR, 0.63; P less than .001).
Findings were similar in a propensity-matched analysis, which showed an 18.1% survival with radiation therapy alone versus 26.4% with concurrent chemoradiation (HR, 0.73; P less than .001).
On recursive partitioning analysis, chemoradiation was associated with better survival among patients 81 years of age or younger who had low comorbidity based on Charlson-Deyo score and either T1-2,N2-3 disease or T3-4,N0-3 disease.
There was no survival benefit in patients older than age 81. And among patients aged 71-80, there was no benefit for those having less advanced disease (stage T1-2,N1) and low comorbidity, or having more advanced disease (T3-4,N1+ disease) and high comorbidity.