Family History of Cancer Important in Screening Assessment

From Medscape Medical News

Pauline Anderson

July 19, 2011 — A family history of cancer, particularly breast and colorectal cancer, that may affect the need for prevention interventions increases with age and is particularly important in early adulthood, a new study suggests.
Cancer-related family history changes up to 3-fold between the ages of 30 and 50 years, according to the authors of the study. They recommend that, for purposes of determining cancer screening, clinicians update a patient's family history every 5 to 10 years.
"If a patient's family history is not updated during early and middle adulthood, the opportunity may be missed to intervene with earlier or more intensive screening that maximizes the likelihood of detecting cancer at an early, treatable stage," write the study authors, led by Argyrios Ziogas, PhD, from the University of California at Irvine.
The study was published in the July 13 issue of the Journal of the American Medical Association.
The aim of the study was to determine how often clinically important changes in cancer family history occur with time that would render a patient at increased risk and therefore a candidate for earlier or intensive screening.
To quantify how often significant changes in family history of breast, colorectal, or prostate cancer occur in adulthood, researchers used data from the Cancer Genetics Network (CGN), a US national registry of people with a personal or family history of cancer. They assessed changes in self-reported family history retrospectively (from birth to enrollment in the CGN) and prospectively (from enrollment to time of last follow-up.)
The analysis included 11,129 participants who were included in 1 or more of the retrospective cancer screening specific analyses; those included in the prospective analyses were a subset of this population.
 
Retrospective Analyses
For colorectal cancer, the analysis found that at age 30 years, 2.1% of participants would have met criteria for early colonoscopy screening. By age 50 years, this trend increased to 7.1% and peaked at approximately 11% at age 70 years. The 10-year rates for newly meeting high-risk screening criteria peaked at a rate of 3 additional people per 100 during ages 40 to 49 years.

For breast cancer, the study found a similar pattern with steady increases in the percentage of participants who would have met criteria for magnetic resonance imaging screening through early and middle age, from 7.2% of women at age 30 years to 11.4% at age 50 years. After age 60 years, the percentage leveled off at approximately 13%. The 10-year rates for meeting high-risk criteria for screening were fairly even from ages 20 to 50 years at 3, 2, and 3 additional persons per 100, respectively, during each respective decade.
Although prostate cancer analysis had similar findings of increasing family history until age 60 years, the overall percentage of men who would have met criteria for early prostate-specific antigen screening was much lower, at 0.9% of men at age 30 years, a rate that increased to only 2.0% by age 50 years. The 10-year rates for newly meeting high-risk screening criteria were also relatively low, remaining constant at 1 additional person who met high-risk screening criteria per 100 followed up for 10 years for men aged 20 to 70 years.
 
Prospective Analyses
The analysis for colorectal cancer found a rate of 1 additional person becoming eligible for enhanced screening per 100 participants followed up for 10 years. The age-specific results suggest that more family history changes occur during their 30s (10-year rate, 2 per 100) than their 40s (10-year rate, 1 per 100).
Analysis of breast magnetic resonance imaging showed that the overall rate of newly meeting criteria for more intensive screening was 3 additional women per 100 followed up for 10 years, with 10-year rates of 0 per 100 among women aged 35 to 39 years, 4 per 100 for women aged 40 to 49 years, and 3 per 100 for women aged 50 to 59 years.
For prostate cancer, the 10-year rate of newly meeting criteria for more intensive prostate-specific antigen screening was 7 per 100 for men younger than 30 years, 5 per 100 for men aged 30 to 39 years, and 3 per 100 for men aged 40 to 49 years. These results may not be in complete agreement with those of the retrospective analysis because of the limited data available, the study authors note.
 
Study Limitations
A limitation of the study was that it relied on reported changes in family history of cancer with time and did not consider an individual's personal medical history or prior cancer screening results, which may change during adulthood and need to be assessed by clinicians, the study authors state. The study also did not evaluate indications for genetic risk assessment and did not assess whether participants who met criteria for high-risk screening actually had this screening.
In an accompanying editorial, Louise S. Acheson, MD, MS, from Case Western Reserve University School of Medicine, Cleveland, Ohio, said that although a family history of cancer is an integral part of medical history and decision making, this information has not, until recently, been standardized or widely recorded in a structured fashion.
"To optimize the use of clinical time and resources, it is important to know when (at what ages and how often) to update the family history of common cancers," she wrote. "Knowing this, health information systems can be designed to accomplish this task. Furthermore, estimating the age-specific prevalence of increased familial risk is important for planning risk-appropriate cancer prevention services."
Having clinicians and patients participate in reviewing and recording family history will become more feasible as electronic health records compile information from all patient caregivers, writes Dr. Acheson.
 
Cost Considerations
However, Dr. Acheson said, increased levels of screening come with some risks and increased costs from, for example, more false-positive test results and test-associated complications. She pointed out that, based on American Cancer Society guidelines and estimates of the current study, approximately 7.2% of women 30 to 40 years old and 8.9% of those 40 to 50 years old would be candidates for both annual breast magnetic resonance imaging and screening mammograms, which cost roughly 10 times more than a mammogram alone.
"It's possible that if family cancer risk status was updated from ages 40-50 years, many lower risk women in that age group may forgo mammography screening," added Dr. Acheson. "The benefits, harms, and empirical results of such an approach are ripe for investigation."
 
The CGN is supported by the National Cancer Institute. The study authors and Dr. Acheson have disclosed no relevant financial relationships.
JAMA. 2011;306:172-178, 208-210.