2017 Section 7 Green Book

Original Article

Figure 1. Health-related quality of life (HRQOL) is illustrated over time from the diagnosis of head and neck cancer for (a) overall study population and (b) each survival group. CI indicates confidence interval. Vertical line at 0 months indicates time of diagnosis.

hazards models. 21 Log(-log) plots were inspected, and sta- tistical tests of the proportional hazards assumption were used to ensure validity of the proportional hazards model. To examine the association of HRQOL with survival, HRQOL from the survey most proximal to HNSCC diagnosis was considered both as a categorical variable by quartile and as a continuous variable per 10-point increase, to obtain hazard ratios (HRs) associated with clinically rele- vant differences in HRQOL ( 1 = 2 of 1 standard deviation, consistent with previous research 22 ). The multivariate model had 80% power to detect an 8% reduction in hazard of death per 10-point increase in the HRQOL score. Statistical analyses were performed using STATA version 11.2 (Stata Corporation, College Station, Tex.). Two-sided P values .05 were considered statistically significant. This study was exempted from review by the Johns Hopkins Bloomberg School of Public Health Institutional Review Board.

(N 5 1006), and 2 or more surveys were available for 39% (N 5 647). Characteristics of the study population are summarized in Table 1.

Trends in HRQOL Over Time From HNSCC Diagnosis

Overall, HRQOL decreased slowly in the 2 to 5 years before HNSCC diagnosis ( D , 2 2.1; 95% CI, 2 5.4, 1.3) (Fig. 1a, Table 2). A steep decline was then observed be- ginning approximately 24 months prediagnosis and cul- minating in a nadir at 13 months postdiagnosis ( D , 2 6.5; 95% CI, 2 8.9, 2 4.1). This was followed by an increase in HRQOL from 13 months until approximately 5 years postdiagnosis ( D , 1 3.9; 95% CI, 2.0-5.9), and finally a steady decline for the remaining 5 years of the study period ( D , 2 3.4; 95% CI, 2 6.9, 0.1). When considering MCS and PCS scores separately (Supporting Fig. 1; see online supporting information), trends over time relative to HNSCC diagnosis were simi- lar to overall HRQOL scores, with the exception that the increase in the MCS score was not significant in the 5 to 10 years postdiagnosis ( D , 1 0.6; 95% CI, 2 1.6, 2.9).

RESULTS Study Population

The study population consisted of 1653 individuals. A single survey was available for 61% of individuals

Cancer

June 15, 2016

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