Jeanne S. Mandelblatt

BACKGROUND: We used modeling techniques to assess the relative and absolute contributions of screening mammography and adjuvant treatment to the reduction in breast-cancer mortality in the United States from 1975 to 2000. METHODS: A consortium of investigators developed seven independent statistical models of breast-cancer incidence and mortality. All seven groups used the same sources to obtain data on the use of screening mammography, adjuvant treatment, and benefits of treatment with respect to the rate of death from breast cancer. RESULTS: The proportion of the total reduction in the rate of death from breast cancer attributed to screening varied in the seven models from 28 to 65 percent (median, 46 percent), with adjuvant treatment contributing the rest. The variability across models in the absolute contribution of screening was larger than it was for treatment, reflecting the greater uncertainty associated with estimating the benefit of screening. CONCLUSIONS: Seven statistical models showed that both screening mammography and treatment have helped reduce the rate of death from breast cancer in the United States.

BACKGROUND: Despite trials of mammography and widespread use, optimal screening policy is controversial. OBJECTIVE: To evaluate U.S. breast cancer screening strategies. DESIGN: 6 models using common data elements. DATA SOURCES: National data on age-specific incidence, competing mortality, mammography characteristics, and treatment effects. TARGET POPULATION: A contemporary population cohort. TIME HORIZON: Lifetime. PERSPECTIVE: Societal. INTERVENTIONS: 20 screening strategies with varying initiation and cessation ages applied annually or biennially. OUTCOME MEASURES: Number of mammograms, reduction in deaths from breast cancer or life-years gained (vs. no screening), false-positive results, unnecessary biopsies, and overdiagnosis. RESULTS OF BASE-CASE ANALYSIS: The 6 models produced consistent rankings of screening strategies. Screening biennially maintained an average of 81% (range across strategies and models, 67% to 99%) of the benefit of annual screening with almost half the number of false-positive results. Screening biennially from ages 50 to 69 years achieved a median 16.5% (range, 15% to 23%) reduction in breast cancer deaths versus no screening. Initiating biennial screening at age 40 years (vs. 50 years) reduced mortality by an additional 3% (range, 1% to 6%), consumed more resources, and yielded more false-positive results. Biennial screening after age 69 years yielded some additional mortality reduction in all models, but overdiagnosis increased most substantially at older ages. RESULTS OF SENSITIVITY ANALYSIS: Varying test sensitivity or treatment patterns did not change conclusions. LIMITATION: Results do not include morbidity from false-positive results, patient knowledge of earlier diagnosis, or unnecessary treatment. CONCLUSION: Biennial screening achieves most of the benefit of annual screening with less harm. Decisions about the best strategy depend on program and individual objectives and the weight placed on benefits, harms, and resource considerations. PRIMARY FUNDING SOURCE: National Cancer Institute.

First implemented in 1990, patient navigation interventions are emerging today as an approach to reduce cancer disparities. However, there is lack of consensus about how patient navigation is defined, what patient navigators do, and what their qualifications should be. Little is known about the efficacy and cost-effectiveness of patient navigation. For this review, the authors conducted a qualitative synthesis of published literature on cancer patient navigation. By using the keywords 'navigator' or 'navigation' and 'cancer,' 45 articles were identified in the PubMed database and from reference searches that were published or in press through October 2007. Sixteen studies provided data on the efficacy of navigation in improving timeliness and receipt of cancer screening, diagnostic follow-up care, and treatment. Patient navigation services were defined and differentiated from other outreach services. Overall, there was evidence of some degree of efficacy for patient navigation in increasing participation in cancer screening and adherence to diagnostic follow-up care after the detection of an abnormality. The reported increases in screening ranged from 10.8% to 17.1%, and increases in adherence to diagnostic follow-up care ranged from 21% to 29.2% compared with control patients. There was less evidence regarding the efficacy of patient navigation in reducing either late-stage cancer diagnosis or delays in the initiation of cancer treatment or improving outcomes during cancer survivorship. There were methodological limitations in most studies, such as a lack of control groups, small sample sizes, and contamination with other interventions. Although cancer-related patient navigation interventions are being adopted increasingly across the United States and Canada, further research will be necessary to evaluate their efficacy and cost-effectiveness in improving cancer care.

PURPOSE: To perform a systematic review of the cost-effectiveness of colorectal cancer screening for the U.S. Preventive Services Task Force. DATA SOURCES: MEDLINE and the British National Health Service Economic Evaluation Database, January 1993 through September 2001. STUDY SELECTION: Original economic evaluations of colorectal cancer screening in average-risk patients were reviewed. The authors sought studies addressing the incremental cost-effectiveness of different screening strategies compared with no screening, of different screening strategies compared with one another, and of different ages of screening initiation and cessation. Two investigators independently reviewed each abstract, and potentially eligible articles were retrieved. A four-member working group reached consensus regarding final inclusion or exclusion of articles. DATA EXTRACTION: One reviewer extracted data into evidence tables. The results were checked by other members and discrepancies resolved by consensus. DATA SYNTHESIS: Among 180 potential articles identified, 7 were retained in the final analysis. Compared with no screening, cost-effectiveness ratios for screening with any of the commonly considered methods were generally between 10, 000 dollars and 25, 000 dollars per life-year saved. No one strategy was consistently found to be the most effective or to have the best incremental cost-effectiveness ratio. Currently available models provided insufficient evidence to determine optimal starting and stopping ages for screening. CONCLUSIONS: Screening for colorectal cancer appears cost-effective compared with no screening, but a single optimal strategy cannot be determined from the currently available data. Additional data regarding adherence with screening over time, complication rates in real-world settings, and colorectal cancer biology are needed. Additional analyses are necessary to determine optimal ages of initiation and cessation.

In several countries, a drop in mortality from breast cancer has been documented starting in 1975. Both early detection by mammographic screening and advances in management are plausible explanations. The National Institutes of Health have used a competitive peer review process to develop 7 independent statistical models of breast cancer incidence and mortality. A consortium of investigators used the same sources to obtain data on screening mammography, adjuvant treatment, and health benefits relating to the rate of death from breast cancer in the years 1975–2000. The use of mammographic screening in women age 40 and over increased markedly over the period 1985 to 2000. The use of adjuvant treatment depended on numerous factors beside the calendar year, including age, tumor stage, and estrogen-receptor status. The proportion of women given adjuvant treatment increased from virtually none in 1975 to approximately 80% in 2000. By 2000, half of all women were using tamoxifen. All 7 models predicted similar proportional reductions in mortality from a combination of screening and adjuvant therapy. The proportion of overall reduction in breast cancer deaths ascribed to screening ranged from 28% to 65% (median, 46%). The remaining decrease in mortality was associated with adjuvant treatment. Variation between models in the absolute contribution of screening was greater than for treatment. Combined screening and adjuvant therapy reduced breast cancer mortality by 25 to 38% (median, 30%). The proportion of decreased mortality ascribed to adjuvant treatment was 12 to 21% (median, 19%). For each of the 7 models, the combination of screening and adjuvant treatment lowered mortality slightly less than the sum of contributions from screening and adjuvant therapy alone. The investigators conclude from these findings that both mammographic screening and adjuvant treatment have helped to lower deaths from breast cancer in the United States.