February 2008 CEBP Highlights

When considering prostate biopsy, men and their physicians must balance the potential benefits of early diagnosis of localized cancer with the implications of over-diagnosis of clinically insignificant cancers. Connolly and team investigated the risk of prostate cancer and prostate cancer specific and all-cause mortality by baseline prostate-specific antigen (PSA) level. PSA level was positively associated with risk of prostate cancer and prostate-specific mortality. In men with baseline PSA <4.0 ng/mL, the rate of prostate cancer and high grade cancer diagnosis was <2 cases and <1 case per 1000 person years respectively, while prostate-specific mortality was very low compared to overall mortality.  

 

The insulin-like growth factor I (IGF-I) axis has been proposed to be a significant factor in the development of certain cancers, including colorectal. However, results from epidemiological studies suggest modest effects on colorectal cancer risk. Jacobs and colleagues investigated whether plasma IGF-I, IGF-1 binding protein, and IGF-I binding protein 3 were associated with colorectal adenoma characteristics at baseline, and whether their levels were related to odds for adenoma recurrence. The authors observed the somewhat unexpected result that baseline IGF-I is inversely associated with recurrence. Their results suggest that once an adenoma is removed, higher IGF-I levels reduce the odds of the formation of new lesions in the colorectum. 

Early adolescent weight may impact the risk of postmenopausal breast cancer, and this association may be modified by a family history of breast or ovarian cancer in a first degree relative, and/or estrogen (ER) and progesterone (PR) receptor status of the disease. Bardia and colleagues found that above average weight at age 12 was inversely associated with risk of postmenopausal breast cancer, and was not modified by a family history of the disease. The inverse association was strongest for ER+/PR– tumors. 

Activity after Breast Cancer Diagnosis Prolongs Survival

Holick et al.

Page 379

Previous studies suggest that increased physical activity may lower the risk of breast cancer incidence, but less is known about whether levels of physical activity after breast cancer diagnosis can influence survival. Holick and investigators prospectively examined the relation between post-diagnosis recreational physical activity and risk of breast cancer death in women who had a previous invasive breast cancer diagnosed between 1988 and 2001 (at ages 20 to 79 years). Women who engaged in greater levels of activity had a significantly lower risk of dying from breast cancer. Results were similar for overall survival and were similar regardless of a woman’s age, stage of disease, and body mass index. 

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Sun Protective Behavior on the Rise

Page 428

Previous population-based surveys to monitor sun protection behavior over time have relied on self-report, which can be subject biases. Dixon and colleagues aimed to describe the prevalence and determinants of observed sun protection behavior whilst engaged in outdoor leisure activities on summer weekends, over a decade of the SunSmart skin cancer prevention program. Significant improvements in the extent of body cover occurred over the decade: the odds of the proportion of people wearing clothes cover above the median level increased by 3% per year. Results suggest that significant gains in sun protective behavior have occurred, coincident with the conduct of an ongoing comprehensive skin cancer prevention program.

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