Re: "differences in socioeconomic status and survival among white and black men with prostate cancer"

Impact of androgen deprivation therapy on racial/ethnic disparities in the survival of older men treated for locoregional prostate cancer

BACKGROUND

Racial disparities persist in prostate cancer (CaP) treatment and survival, but disparities in androgen deprivation therapy (ADT) and the degree to which it affects racial differences in survival remains to be fully assessed.

METHODS

Using the Surveillance, Epidemiology and End Results-Medicare linked data, we examined a large cohort of men (N = 64,475) diagnosed with locoregional CaP during 1992 to 1999 and followed through 2003. The effects of ADT and race on survival were analyzed using a Cox proportional hazards model.

RESULTS

The receipt of ADT was significantly lower in African Americans (24%) relative to Caucasians (27%), Asians (34%), and Hispanics (28.7%) (P < .05). Compared with Caucasian race, African American race was associated with a statistically significant increased mortality (HR = 1.26, 95% CI = 1.21-1.32), which remained significant after adjusting for ADT but was substantially decreased after controlling for primary therapies such as radical prostatectomy, radiation, and watchful waiting (HR = 1.06, 95% CI = 1.01-1.10) and was no longer statistically significant after controlling for comorbidities (HR = 0.98, 95% CI = 0.94-1.03).

CONCLUSIONS

There were marked racial variations in the receipt of ADT, primary therapies (namely surgery and surgery combined with radiation), and comorbidities. However, racial disparities in survival were not affected by racial variations in ADT but were explained by racial variations in primary therapies and by racial differences in comorbidities.

Absence of a correlation of androgen receptor gene CAG repeat length and prostate cancer risk in an African-American population

Shorter androgen receptor gene CAG repeat length has been associated with an increased risk of prostate cancer, an earlier age of onset, and more advanced stage of disease. Studies comparing the distribution of CAG repeat lengths within different populations have reported that racial groups with higher prostate cancer incidence also have shorter CAG repeat lengths. We evaluated CAG repeat length in 685 black men in Louisiana, South Carolina, and the District of Columbia who were participating in prostate cancer screening, comparing the 118 who were diagnosed with prostate cancer with 567 who had normal serum prostate-specific antigen levels and no evidence of cancer on digital rectal examination. The median CAG repeat length was 21 among cases and 19 among controls (P = 0.11). Cases were significantly older than controls, with a median age of 68 years compared with 54 years (P < 0.0001). After adjusting for age, we found no association between prostate cancer risk and CAG repeat length (odds ratio, 1.05; 95% CI, 0.98-1.13; P = 0.16). Dividing CAG repeat lengths into septiles and calculating the odds ratio for each revealed no specific repeat-length range with a significantly elevated or depressed risk of prostate cancer, but a trend test showed a significant association between longer CAG repeat lengths and an elevated risk of prostate cancer (P = 0.02). Neither grade nor stage was associated with CAG repeat length. This study confirms earlier reports that black men have shorter CAG repeat lengths than reported white and Asian populations. We did not find an increased risk of prostate cancer among black men with fewer CAG repeats.