Breast cancer screening and diagnosis in British Columbia

Although major gains have been made in improving outcomes for breast cancer patients over the past two decades, women continue to be deeply concerned about how the system is organized. According to a Canadian Breast Cancer Foundation study, both women and care providers see the process of obtaining a breast cancer diagnosis in BC as “emotionally troubling and structurally problematic.” Wo men describe their experience as a journey through a diagnostic “maze.” A comparison of service in BC with national and international service guidelines suggests there is room for improvement. The process for early detection and diagnosis of breast cancer in BC is marked by both too little and too much service. Many women do not participate in the screening program. Furthermore many women undergo more diagnostic procedures than required, and these procedures either do not provide adequate information for adjuvant treatment planning or are more invasive than necessary. Des pite these problems, BC’s 5-year survival rates for breast cancer are among the best in the world. To maintain these rates and improve on them, the BC system will need to encourage greater participation in screening and provide better access to core biopsy and tumor marker pathology. E ven though breast cancer is a major killer of women, especially women age 35 to 64, mortality rates have de clined steadily since 1986. This improvement has been attributed to two main factors: • Increased screening, which has allowed for earlier and thus more effective intervention. • Improved treatment with adjuvant therapies. The Cancer Intervention and Sur veillance Modeling Network of the National Institute of Health attempted to define the respective contributions of increased screening and advances in adjuvant therapies while accounting for changes in background risks. Breast cancer screening and diagnosis in British Columbia We need to update our provincial practices to ensure that BC continues to be among the jurisdictions with the best breast cancer survival rates in the world. Barbara Poole, MPA, Karen Gelmon, MD, Marilyn Borugian, PhD, Lisa Kan, MSc, Moira Stilwell, MD Ms Poole is a health service policy and research analyst with the BC Cancer Agency (BCCA) and a doctoral student in the School of Health Care and Epidemi ology at the University of British Columbia, under the supervision of Dr Charlyn Black. Dr Gelmon is the former head of the Breast Tumour Group at the BCCA. Dr Borugian is a scientist with the BCCA. Ms Kan is the operations leader of screening programs at BCCA. Dr Stilwell is president of the Canadian Breast Cancer Foundation, BC/ Yukon division. 198 BC MEDICAL JOURNAL VOL. 50 NO. 4, MAY 2008 suggest that 2849 women will have been diagnosed with breast cancer in BC by 2007, and that this number will grow to 3619 by 2017, an increase of 27%. Breast health care guidelines The BC Cancer Agency develops cancer management guidelines through various “tumor groups,” whose members review the latest evidence for the care of cancer types. Clinical guidelines developed by the BCCA focus on detection, diagnosis, and treatment paths. In BC women age 40 to 79 can refer themselves to the Screening Mammography Program (SMPBC). Women younger than 40 with a strong family history of breast cancer and women older than 80 require a referral to the program from a family doctor. The SMPBC recommends that women age 40 to 49 be screened every 12 to 18 months and women age 50 to 79 be screened every 2 years. The current BCCA guidelines for diagnosis of breast cancer (available on the agency’s web site) include the following recommendations: • Diagnostic mammograms should be performed if there is any suspicious finding on a screening mammogram or if there is a palpable finding. • Abnormalities detected by mammography may take the form of either a mass, a change in breast architecture, or abnormal calcifications within the breast. • If there is an abnormality that is not clearly malignant but is new, further imaging with additional views and magnification views should be un dertaken. • A suspicious new finding should be further assessed with imaging and a pathological diagnosis. A stereotactic core biopsy under mammographic guidance may be undertaken. • If the diagnostic radiologist thinks the mass may be benign (e.g., there is a strong possibility it is a nonpalpable cyst or a small fibroadenoma), then an ultrasound examination may help distinguish between a cystic and a solid lesion. • If the lesion is likely cystic, then aspiration of the lesion under ultrasound control by the diagnostic radiologist may both diagnose and treat the abnormality, and may be all the treatment that is needed. • If the lesion is found to be solid on ultrasound, or if the mammographic appearances are not clearly those of a benign abnormality, then one or more of the following are manda tory, depending on the level of suspicion and on the size and discreteness of the lesion: fine needle aspiration under ultrasound guidance, stereotactic core needle biopsy, or open surgical biopsy guided by fine wire localization. • A core biopsy is strongly recommended to obtain adequate tissue for pathological diagnosis and to plan surgical intervention if necessary. • Where a cluster of fine calcifications is identified and the diagnostic radiologist finds the appearance sufficiently suspicious, a stereotactic core needle biopsy or an open bi opsy is required. Given the current state of our knowledge about effective intervention, it is particularly important to consider health care service guidelines for population-based screening, high-risk screening, and diagnosis. Population-based screening The Public Health Agency of Ca na da (PHAC) reviewed international service guidelines for populationbased screening in 1997. uses the PHAC format to provide the most re cent information about these Table 1 Breast cancer screening and diagnosis in British Columbia The results of this modeling estimated that the observed mortality decline between 1990 and 2000 was 23.5% for women age 30 to 79. The decline in mortality due to screening and early intervention was 8% to 23%, while the decline due to improved adjuvant therapy was 12% to 21%. Breast cancer is a heterogeneous disease. Specific molecular attributes of the disease must be identified before systemic treatment recom mendations can be made. As adjuvant therapy options are now based on the specific pathological characteristics of tumors, the identification of these characteristics is a critically important part of the detection and initial diagnosis of cancer. Despite the decline in mortality rates, women in British Columbia have expressed deep concern about how the breast health system is organized. According to a Canadian Breast Cancer Foundation study from 2001, both women and care providers see the process of obtaining a breast cancer diagnosis in BC as “emotionally troubling and structurally problematic.” Women describe their experience as a journey through a diagnostic “maze.” Breast cancer epidemiology The lifetime risk of breast cancer is 1 in 9 for women in BC. Approximately 2700 BC women are diagnosed with breast cancer annually. Incident rates have been relatively stable over time. However, the demography of BC indicates that we will see higher incidence rates in the next few years. The number of women age 40 to 79 is expected to grow 21.4%, from 1 020 484 in 2007 to 1 239 286 in 2017. Because breast cancer risk increases with age, the growth in this older age group, the 50 to 79 subgroup, will result in an increased incidence of cancer. BC Cancer Agency BCCA projections 199 VOL. 50 NO. 4, MAY 2008 BC MEDICAL JOURNAL Canada Sweden Europe United Kingdom Australia Age group 50–69 50–64 50–64 50–69 Attendance rate 70% No specific guideline Acceptable: ≥70% Desirable: ≥75% Acceptable: ≥70% Desirable: ≥80% ≥70% Retention rate ≥75% within 30 months No specific guideline Acceptable: ≥95% Desirable: ≥100% Acceptable: ≥90% Desirable: ≥100% ≥75% screened (of those rescreened, >90% to be screened biennially) Abnormal recall rate* Initial screen <10% Rescreen <5% 9% (overall) Initial Screen Acceptable: <7% Desirable:<5% Rescreen Acceptable: <5% Desirable: <3% Initial screen Acceptable: <10% Desirable: <7% Rescreen Acceptable: <7% Desirable: <5% Initial screen <10 %