JAMA: Breast, colon cancer screening needs change with age
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| CT Colonoscopy |
One of the most important determinants of an individual's risk of cancer is family history, and the details of that history—whether and at what age close relatives were diagnosed with particular tumors—can affect recommendations for screening examinations such as colonoscopies and mammograms.
Approximately 22 percent of individuals have a family history that suggests familial or hereditary predisposition to cancer, according to Argyrios Ziogas, PhD, of University of California, Irvine, and colleagues. However, little is known about how risk changes over time and if those changes may qualify patients as candidates for earlier or more intense screening.
"We wanted to find out whether changes in a person's family history of cancer, over time, would affect the screening schedule and tests recommended by standard guidelines," said Dianne Finkelstein, PhD, of the Massachusetts General Hospital (MGH) Biostatistics Center, corresponding author.
The study investigators are all members of the National Cancer Institute-funded Cancer Genetics Network (CGN), which involves 14 academic medical centers in the U.S. Established in 1998, the CGN is a registry of thousands of individuals with a personal or family history of cancer. The researchers analyzed both the detailed family history information participants reported upon enrollment in the network—which reflected their cancer risk up until that time—and the updated information they provided on an annual basis over an average of eight years.
Analysis focused on colorectal, breast and prostate cancer, because the established screening guidelines for those common tumors can be affected by family history.
The retrospective portion of the study, from birth to CGN enrollment, included 9,861, 2,547 and 1,817 participants for colorectal, breast and prostate cancers, respectively. The prospective portion, from CGN enrollment to the most recent follow-up, included 1,533, 617 and 163 participants for colorectal, breast and prostate cancers, respectively.
The retrospective analysis indicated that 2.1 percent of participants at age 30 would have met criteria for colonoscopy screening, with the percentage increasing to 7.1 percent by age 50 and peaking at 11 percent at age 70.
Findings were similar for breast cancer risk, wrote the authors, “with steady increases in the percentage of participants who would have met criteria for MRI screening through early and middle age, from 7.2 percent of women at age 30 to 11.4 percent at age 50.”
Although the retrospective analysis showed an increase in the percentage of men meeting criteria for early PSA screening, it remained relatively low, increasing to 2 percent by age 50.
The prospective colorectal cancer analysis found that 15 of the 1,533 participants reported changes in family history that altered their risk, resulting in a 10-year rate of one additional person eligible for enhanced screening per 100 participants followed up for 10 years.
The prospective breast MRI analysis found that the overall rate of newly meeting criteria for more intensive screening was three additional women per 100 women followed up for 10 years.
The prospective prostate cancer analysis found that the overall rate of newly meeting criteria for more intensive screening was four additional men per 100 men followed up for 10 years, reported the authors.
“Both analyses demonstrate that clinically relevant family history changes substantially during early and middle adulthood, particularly for colorectal and breast cancer, for which the percentage recommended for high-risk screening increases 1.5- to 3-fold between ages 30 and 50 years,” wrote Ziogas et al.
Overall, the researchers calculated a 5 percent chance that an individual’s colorectal cancer screening recommendation would change between age 30 and 50 based on family history, and that 4 percent of women would become candidates for MRI screening.
The authors noted that several studies have documented that patients do not receive adequate familial cancer risk assessment in primary care settings and suggested that subsequent updates focusing on new diagnoses among living first- and second-degree relatives be added to standard patient questionnaires. In addition, EMRs could prompt physicians to update risk and alert them to changes in a patient’s criteria for high-risk screening.
Ziogas and colleagues recommended that, in addition to taking comprehensive family histories of new patients, primary care physicians or other healthcare providers should update those histories every five to 10 years, particularly for patients between the ages of 30 and 50.