Note: A summary of the recommendations can be found in Table 5 in the original guideline document.
Staging
Before Surgery
Until further information becomes available, magnetic resonance imaging (MRI) and mammography are both useful tools to determine the extent of disease in women with operable breast cancer. The choice between those modalities should be made based on the particular conditions of each patient and the equipment availability to handle the increased workload that would entail. However, MRI should not be used as a substitute for detailed mammographic or sonographic work-up of any abnormalities detected at a routine screening or as a substitute for the clinical or image-guided core biopsy of mammographic, sonographic, or clinical abnormalities. Pathology is the gold standard. Subsets of patients that may benefit from MRI include:
- Women with clinically palpable and mammographically occult breast cancer.
- Women with metastatic adenocarcinoma to axillary lymph nodes, with an unknown primary (normal mammogram and ultrasound)—75% to 85% of breast malignancies will be detected by MRI in these cases, and most will be <2 cm.
- Women with lobular carcinoma. That histology is associated with a higher risk of multifocal and multicentric spread, and the extent is frequently underestimated mammographically and sonographically. MRI is not perfect in this area and may also underestimate the extent of disease; however, it is more sensitive than standard imaging.
- Patients who require re-excision because of positive surgical margins may benefit from the increased sensitivity of MRI. The group of patients with >50% dense fibroglandular tissue (Breast Imaging Reporting and Data System [BIRADS] densities 3 or 4), may benefit the most.
- Patients with a high risk of multifocal disease may warrant an MRI. The youngest patients (24 to 39 years) have significant multifocality not detected on routine imaging. Their surgical treatment is frequently dramatically altered by MRI.
After Surgery
The practice guideline issued by Cancer Care Ontario's Program in Evidence-Based Care (PEBC) should be followed. That guideline applies to women with newly diagnosed breast cancer who have undergone surgical resection, and who have no symptoms, physical signs, or hematological or biochemical evidence of metastases.
- In women with intraductal and pathological stage I tumours, routine bone scanning, liver ultrasonography, and chest radiography are not indicated as part of baseline staging.
- In women who have pathological stage II tumours, a postoperative bone scan is recommended as part of baseline staging. Routine liver ultrasonography and chest radiography are not indicated for that group.
- In women with pathological stage III tumours, bone scanning, liver ultrasonography, and chest radiography are recommended postoperatively as part of baseline staging.
- In women for whom treatment options are restricted to tamoxifen or hormone therapy, or for whom no further treatment is indicated because of age or other factors, routine bone scanning, liver ultrasonography, and chest radiography are not indicated as part of baseline staging.
Response
Locally Advanced Breast Cancer
In the follow-up of locally advanced breast cancer patients receiving adjuvant chemotherapy, mammography and ultrasound are not accurate at assessing tumour response. Clinical assessment is subjective and lacks accuracy as well. MRI will determine whether the tumour is responding to chemotherapy, which does have long-term prognostic implications. As well, it will determine which tumours do not respond to chemotherapy, in which case the therapeutic regime could be altered.
Metastatic Breast Cancer
In order to determine if a treatment is successfully causing tumour regression or stability and inform decisions about continuing, changing, or stopping therapy, imaging tests that are abnormal at baseline could be repeated every three or four months. The one exception to this process would be bone scanning, which can be misleading in follow-up, as healing can look very similar to new disease in bone. If a patient is diagnosed with metastatic breast cancer, staging is required to identify the full extent and patterns of spread to determine if the patient should be treated with hormonal therapy instead of chemotherapy.
Follow-up
The Canadian practice guideline issued by the Steering Committee on Clinical Practice Guidelines for the Care and Treatment of Breast Cancer should be followed. In patients who have been treated curatively, routine imaging tests to detect distant metastases should not be carried out.
Diagnosing Recurrence
Patients who develop symptoms or signs suggestive of recurrence require individualized testing to determine if recurrence has occurred. Recurrent breast cancer may be difficult to fully assess on mammography due to scarring and inflammation from previous surgery or radiation. If the patient is a candidate for repeat lumpectomy, MRI should be considered.
