Thomas Hickey

Race and Colorectal Cancer Disparities: Health-Care Utilization vs Different Cancer Susceptibilities

BACKGROUND It is unclear whether the disproportionately higher incidence and mortality from colorectal cancer among blacks compared with whites reflect differences in health-care utilization or colorectal cancer susceptibility. METHODS A total of 60, 572 non-Hispanic white and black participants in the ongoing Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial underwent trial-sponsored screening flexible sigmoidoscopy (FSG) without biopsy at baseline in 10 geographically dispersed centers from November 1993 to July 2001. Subjects with polyps or mass lesions detected by FSG were referred to their physicians for diagnostic workup, the cost of which was not covered by PLCO. The records of follow-up evaluations were collected and reviewed. We used log binomial modeling with adjustment for age, education, sex, body mass index, smoking, family history of colorectal cancer, colon examination within previous 3 years, personal history of polyps, and screening center to examine whether utilization of diagnostic colonoscopy and yield of neoplasia differed by race. RESULTS Among 57 561 whites and 3011 blacks who underwent FSG, 13,743 (23.9%) and 767 (25.5%) had abnormal examinations, respectively. A total of 9944 (72.4%) whites and 480 (62.6%) blacks had diagnostic colonoscopy within 1 year following the abnormal FSG screening. When compared with whites, blacks were less likely to undergo diagnostic evaluation (adjusted risk ratio = 0.88, 95% confidence interval = 0.83 to 0.93). Overall, among subjects with diagnostic colonoscopy (n = 10 424), there was no statistically significant difference by race in the prevalence of adenoma, advanced adenoma, advanced pathology in small adenomas (high-grade dysplasia or villous histology in adenomas <10 mm), or colorectal cancer. CONCLUSIONS We observed a lower follow-up for screen-detected abnormalities among blacks when compared with whites but little difference in the yield of colorectal neoplasia. Health-care utilization may be playing more of a role in colorectal cancer racial disparity than biology.

Prostate cancer screening in the Prostate, Lung, Colorectal and Ovarian cancer screening trial: update on findings from the initial four rounds of screening in a randomized trial.

To describe the results of the first four rounds (T0‐T3) of prostate cancer screening in the Prostate, Lung, Colorectal and Ovarian (PLCO) cancer screening trial (designed to determine the value of screening in the four cancers), that for prostate cancer is evaluating whether annual screening with prostate‐specific antigen (PSA) and a digital rectal examination (DRE) reduces prostate cancer‐specific mortality.

Serum prostate-specific antigen hemodilution among obese men undergoing screening in the prostate, lung, colorectal, and ovarian cancer screening trial

Background: Previous studies have shown an inverse relationship between prostate-specific antigen (PSA) concentration and body mass index (BMI). It has been recently proposed that this relationship may be explained by the larger plasma volume of obese men diluting a fixed amount of PSA (hemodilution effect). We examined this hypothesis in a cohort of men enrolled in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. Methods: Of 38,349 men ages 55 to 74 years randomized in PLCO to receive annual PSA and digital rectal examination screening, 28,380 had a baseline PSA, complete demographic information, and no prostate cancer diagnosis within 6 years from baseline. Self-reported height and weight were used to calculate BMI and to estimate plasma volume. PSA mass was estimated as PSA concentration times plasma volume. Multivariable linear regression models were used to investigate the relationship between PSA concentration, plasma volume, PSA mass, and BMI. Results: PSA concentration significantly decreased with increasing BMI (P < 0.001); mean PSA values were 1.27, 1.25, 1.18, and 1.07 ng/mL among normal (BMI, 18.5-25), overweight (BMI, 25-30), obese (BMI, 30-35), and morbidly obese (BMI, >35) men, respectively. However, plasma volume also increased with increasing BMI and PSA mass showed no association with BMI, with mean values of 3.78, 3.95, 3.97, and 3.82 μg across the four BMI categories (P = 0.10). Conclusions: This study confirms earlier findings that the inverse relationship between PSA concentration and BMI may be explained by a hemodilution effect. These findings could have implications for prostate cancer screening in large men. (Cancer Epidemiol Biomarkers Prev 2009;18(3):748–51)

Modified Gleason Grade of Prostatic Adenocarcinomas Detected in the PLCO Cancer Screening Trial

PURPOSE We determined the modified Gleason grade of prostatic adenocarcinomas detected in PLCO to assess grade distribution and compare modified Gleason grades of cancer detected in the intervention arm (organized annual screening) vs the control arm (opportunistic screening). MATERIALS AND METHODS Modified Gleason grading was performed in 859 radical prostatectomy cases by a single urological pathologist. We compared the proportion of cases with high grade disease in the screened arm vs the control arm by logistic regression analysis. RESULTS In the intervention arm a modified Gleason score of 5, 6, 7 (3+4), 7 (4+3), 8, 9 and 10 was assigned in 3.6%, 43.3%, 39%, 7.4%, 3.5%, 3.2% and 0.1% of cases, respectively. In the control arm a modified Gleason score of 5, 6, 7 (3+4), 7 (4+3), 8, 9 and 10 was assigned in 3.0%, 35.7%, 46.4%, 7.1%, 5.4%, 1.9% and 0.5% of cases, respectively, after correcting for high grade disease over sampling. A high grade modified Gleason score of 7 or greater was detected in 53% of cases in the intervention arm vs 61.3% in the control arm after correction (p=0.019). The median modified Gleason score was 7 (3+4) in each arm. CONCLUSIONS A significant percent of cancers in each arm had a component of high grade disease. The modified Gleason grade of prostate cancers detected by organized annual screening was slightly lower than the modified grade of those detected by opportunistic screening. This is an expected consequence of more intensive screening.