Lansdorp-Vogelaar et al. Page 728

Disparities in colorectal cancer (CRC) incidence and mortality rates between blacks and whites in the United States are considerable. How many of these disparities can be explained by differences in CRC screening practices? Using the MISCAN-Colon microsimulation model, Lansdorp-Vogelaar and colleagues simulated life histories from birth to death to estimate CRC progression in the absence of screening. They report that differences in screening practices between white and black U.S. residents are responsible for a substantial proportion of black/white disparities in CRC incidence and mortality rates. The authors suggest that enabling blacks to achieve equal access to health care could reduce these disparities.

Buist et al. Page 720

In the United States, mammography use and breast cancer rates have both declined over the past decade. Are these declines due to a reduction in hormone therapy use as well as changes in screening practices of hormone therapy users? To address this question, Buist and colleagues tracked hormone therapy use, mammography screening, and breast cancer rates in the same cohort of 163,490 women between 1994 and 2009. They report that differential screening mammography rates by hormone therapy use do not explain the decline in invasive breast cancer rates. The authors recommend that future breast cancer surveillance should focus on age-specific incidence, histologic subtypes, tumor characteristics, and outcomes following diagnosis.

Stevens et al. Page 747

Obesity is an established risk factor for endometrial cancer in postmenopausal women; however, it is not clear if weight cycling (repeated cycles of weight loss and regain) is also a risk factor. Stevens and colleagues evaluated the endometrial cancer risk of weight cycling in women in the Cancer Prevention Study II Cohort. They report that weight cycling was not positively associated with endometrial cancer incidence after adjustment for body mass index. These results encourage women to strive for weight loss as a means to lower their risk of endometrial cancer.

Guo et al. Page 780

Guo and colleagues examined risk factors for esophageal squamous cell carcinoma (ESCC) in high-incidence areas of China. The presence of human papilloma virus (HPV) DNA and HPV-16–specific antibodies was assessed in ESCC cases and controls. The study revealed that the presence of HPV-16 was particularly associated with ESCC and that antibodies against HPV-16 E7 protein were found in higher proportions in cases versus controls. These results support a significant role for HPV infection in ESCC development in high-incidence areas of China.