Cancer Treatment Today » Imaging

Breast tomosynthesis: a new mammography

M Levin, MD — Fri, 24 Aug 2012 17:59:49 +0000

Breast tomosynthesis is a 3-dimensional (3-D) imaging technology that involves acquiring images of a compressed breast at multiple angles during a short scan. It is more comfortable than standard mammography. The individual images are then reconstructed into a series of thin high-resolution slices that displayed individually or in a dynamic movie-like mode. Tomosynthesis can reduce or eliminate the tissue overlap effect. While holding the breast stationary, images are acquired at a number of different x-ray source angles. Objects at different heights in the breast project differently for each angle. The final step in the tomosynthesis procedure takes advantage of this fact and reconstructs the data to generate images that enhance objects from a given height by appropriate shifting of the projections relative to one another. Tomosynthesis has many properties that make it suitable as a modality for screening, including good diagnostic performance, short examination time and low radiation dose. It may become a strong competitor to the current gold standard breast screening modality, i.e. mammography. At the same time, theoretical advantages have not yet been shown to translate into clinical advantage or even equivalence to standard mammography.

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MRI to screen preoperatively for DCIS

M Levin, MD — Wed, 20 Jun 2012 22:41:48 +0000

Most guidelines recommend breast MRI for screening in women with genetically high-risk of developing breast cancer and to clarify diagnostic uncertainties after mammography and ultrasound. As use of MRI has increased, many other situations for which, MRI might be helpful came to the fore. Unfortunately, literature support for most of them, is still lacking.

One of these new situations is the use of MRI to decide between a mastectomy and the lumpectomy. In the presence of DCIS lumpectomy also leaves behind disease, requiring re-resections. It might, therefore, be useful to know about the presence of the CAS before lumpectomy. Some physicians adopt the strategy of using MRI to identify DCIS and to eschew lumpectomy based on results. The reasoning is that if widespread DCIS is found, a mastectomy would be performed rather than a lumpectomy. This strategy has not been formally evaluated and is not currently recommended by guidelines. A clinical trial is ongoing: Breast MRI as a Preoperative Tool for DCIS, NCT00605982. The purpose of this study is to see how often MRI can find other areas of cancer in women with one area of breast cancer, and to determine how having the MRI test affects their treatment. The study also aims to follow women who enter the study over a 10-year period to determine how often the breast cancer comes back.

American College of radiology (ACR) says: ” Invasive carcinoma and ductal cardinoma in situ (DCIS) – Breast MRI may be useful to determine the extent of disease and the presence of multifocality and multicentricity in patients with invasive carcinoma and ductal carcinoma in situ (DCIS). MRI can detect occult disease up to 15% to 30% of the time in the breast containing the index malignancy. MRI determines the extent of disease more accurately than standard mammography and physical examination in many patients. It remains to be conclusively shown that this alters recurrence rates relative to modern surgery, radiation, and systemic therapy.”

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Preoperative MRI for Breast Cancer

M Levin, MD — Wed, 20 Jun 2012 17:28:24 +0000

The use of MRI before breast surgery is increasing based on reports that show that MRI can detect previously unknown foci of breast cancer in a substantial number of women with a new diagnosis of breast cancer. However, some argue that MRI will increase the proportion of mastectomy because it will cause more extensive surgeries. Since breast conservation surgery combined with radiation therapy as major advantages with similarly low recurrence rates and equivalent mortality, an increase in the rate of mastectomy prompted by MRI findings would be a negative development. Since studies have shown equivalent outcomes for lumpectomy with radiation and mastectomy, the implied argument is that the MRI just cause more extensive surgeries and not improve the results. Even if some foci are missed, preoperative MRI would have little or no impact on rates of recurrence or death because of post-operative radiation. For this reason, MRI should not be used routinely in the workup of new breast cancers.

At this time the effectiveness of radiation in eradicating residual foci of disease as compared to its surgical removal, is not known. Detecting widespread disease can obviate inappropriate attempts at conservation. Knowledge of the extent of disease can help patients select the most appropriate treatment options. A staging MRI examination showing only a single cancer lesion may permit the patient to choose conservation therapy with a high degree of confidence that no macroscopic disease will be missed at surgery.

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