Explanation of Measures
1. The number of cancers found per 1,000 women screened (screening detection rate)
Mammography's purpose is to find breast cancers. Ideally mammography would find all breast cancers without any false alarms known as "false positives." Technology and training improvements in this area have taken place over the last 2 decades and improvements are continuing today. Studies from published academic research show that on average, a mammography provider can expect to detect 6 cancers per 1,000 screening mammograms (4). But this varies depending on whether the women they are screening receive mammograms regularly or have never or rarely been screened for breast cancer. At facilities where most of the women have not been previously screened, a higher screening detection rate is expected (up to 10 cancers per 1,000 screens). At facilities where women have been regularly screened a lower screening detection rate (as low as 2 cancers per 1,000 screens) is expected. In addition, facilities with high-quality screening mammography and diagnostic follow-up would be expected to have a higher cancer detection rate. Therefore, if a hospital knows that the women they serve have generally not received prior mammograms or have rarely received them but their detection rate is low, this would be a warning sign. More investigation would be needed to understand why the detection rate is low and to help identify potential areas for quality improvement.
2. The proportion of cancers detected that are small or "minimal"(DCIS, ≤ 1 cm)
3. The proportion of cancers detected that are early stage (Stage 0, 1)
Finding breast cancer early when the tumors are small and at their earliest stage is key to saving lives. Minimal breast cancer is defined as cancer that is diagnosed as either ductal carcinoma in-situ (DCIS) or that is less than or equal to 1cm in diameter. One goal of screening mammography is to increase the percentage of minimal cancers that are detected because these cancers have the best chance of being successfully treated. When women do not regularly receive mammograms we expect to have fewer minimal cancers. This is because cancer tends to be found later in these women and therefore is likely to be diagnosed as a larger tumor and at a more advanced stage. Likewise, when women are screened regularly we expect to have far more minimal cancers. In addition, facilities with high-quality screening mammography and diagnostic follow-up would be expected to have a high percentage of minimal cancers detected (i.e., they wouldn't miss the small cancers). Therefore, if a hospital knows that their population is regularly screened but their percentage of minimal cancer is low, this might raise a red flag. Further study might be needed to understand what exactly is going on which may help identify potential areas for quality improvement.
4. The proportion of women with abnormal mammograms who receive follow up (recall rate)
If the interpreting radiologist notes a suspicious finding on a screening mammogram, the patient is notified that she needs to return for additional diagnostic imaging. Recall rate refers to the percentage of screening mammograms that are interpreted as suspicious and that require some sort of diagnostic follow-up imaging and/or biopsy. According to the American College of Radiology the percentage of patients recalled following a screening mammogram should be 10% or less (5). Similar to the other measures, the recall rate is influenced by a number of factors, and an exceptionally high or low recall rate indicates a need for further study to help identify potential areas for quality improvement. For patients who are recalled, the timeliness of follow-up imaging is important. Additional delays allow more time for a potential cancer to grow, spread, and become less treatable.
5. Timeliness of diagnostic follow-up imaging
Mammography allows us to find breast cancer and to have it treated in a timely manner. Time is of the essence because delays can allow the cancer to continue to grow and spread before it can be successfully treated (6). The benefits of going routinely for a mammogram could be diminished if patients experience long delays in getting diagnosed following an abnormal screen. We considered timely diagnostic follow-up to take place if follow-up imaging occurred within one month of an abnormal screening mammogram. Timeliness of follow-up may depend on a patient's own behavior, which can be affected by fear, family responsibility, resources and other factors in their lives, but will also depend on facility practices and availability of appointments. The percentage of patients with timely follow-up will tend to be higher at facilities that interpret and report mammogram findings to patients promptly and make appointments available for quick follow-up. If a facility serves women who have many barriers to accessing care such as lack of transportation, difficulty in taking time off work, money concerns or other barriers, timeliness may suffer. In such instances, case managing or patient navigation services may help to ensure that women get the follow up care they need in a timely fashion.
The treatment measures we selected are based on widely accepted breast cancer treatment recommendations and guidelines supported by the American College of Surgeons - Commission on Cancer (ACOS-CoC), the American Society of Clinical Oncology (ASCO), the National Comprehensive Cancer Network (NCCN), the National Qualify Forum (NQF) and other quality entities. Research has demonstrated that the percentage of patients in each of the categories below should be as high as possible. However, some patients do not get timely treatment or the most effective treatments for their cancer either because they are not offered these treatments by their providers, they cannot afford certain treatments, they fear potential side effects of treatments, or they face other barriers. If the percentage of patients receiving the most appropriate treatment is low it suggests that clinical guidelines in breast cancer care are not being met by providers and could point to an area for improvement.
The treatment measures chosen by the Consortium include the following:
1. Percentage of women who begin treatment for their breast cancer within 30 days of diagnosis
Delays before treatment begins can allow cancer to grow and spread. The larger and more wide-spread cancer is, the less likely it is that treatment will be successful. We consider treatment following diagnosis to be timely if the treatment began within one month of the date of the diagnosis. As stated before, if a facility serves women who have many barriers to accessing care, timeliness may suffer. In such instances, case managing or patient navigation services may help women get the timely follow up care needed.
2. Percentage of women with breast conserving surgery who go on to receive radiation therapy
Breast conserving surgery (BCS) refers to cases where women have had part of the breast but not the whole breast removed. This can include lumpectomies (removing a lump) and partial mastectomies (removing part of the breast). Studies have shown that simply removing a cancerous lump or segment of the breast can be as effective as removing the whole breast (known as mastectomy) if it is accompanied by local radiation treatment aimed at the area where the lump was removed (7,8). Radiation therapy decreases the chance that the breast cancer will return. Ideally, all patients with BCS would also receive local radiation.
3. Percentage of women who have tumors with hormone receptors on them that go on to receive hormonal therapy as part of their treatment
Breast cancers that have receptors (i.e. are positive) for the hormones estrogen and progesterone tend to be easier to treat and these tumors tend to shrink if patients are given hormone therapy (7). Ideally, all patients with hormone-receptor positive breast cancer would also receive hormonal therapy.
4. Percentage of women who have tumors with a specific receptor known as her2/neu on them that go on to receive the chemotherapy drug Herceptin as part of their treatment
Breast cancers that have the growth factor receptor known as her2/neu have a better chance of successful treatment if given the drug Herceptin (7,9). Ideally, all patients whose breast cancer contains this receptor would receive Herceptin.