Once cancer cells invade through the duct or lobule in which they arise, they are called invasive cancers. Invasive cancers traveling though the non-glandular substance of the breast can gain access to lymph channels and blood vessels that can take them anywhere in the body. This process of spread elsewhere is called metastasis.

If we assume that a single cell with a biologic error ultimately leads to a clinical breast cancer, some estimate that the time from origin to diagnosis may be between 5 and 7 years. By the time of diagnosis, metastasis of microscopic cells may have already taken place. Unfortunately, it is these micro metastases which ultimately become the cause of breast cancer mortality. Although they may be present at diagnosis, their presence may not become clinically evident for many years.

The goal of treatment for new breast cancers is to:

1) Erradicate the local breast disease process.

2) Treat potential micrometastases while they too can be erradicated.

No matter how big the breast surgery, it cannot treat distant metastases. That is why bigger operations do not impact survival, as long as local disease control can be established.

Lumpectomy and mastectomy are the two local approaches for disease control. At least 70% of patients have primary tumors that may be managed by breast conservation techniques like lumpectomy. A much smaller group have multiple disease sites, or relatively large tumors for which mastectomy is a better choice. Some patients have genetic germline mutations that indicate a high risk for future new disease, and as a result choose mastectomy partly for prevention. However, for the patient in whom lumpectomy is a reasonable choice, it is just as good as mastectomy in terms of long term outcome and survival.

The use of oncoplastic techniques to re-arrange breast tissue, and even change the breast skin envelope, allows larger tumors, and even multiple tumors, to be removed with satisfactory margins. Although the resulting breast may be somewhat smaller that before, it can be refashioned to have a good, or even better and younger shape and contour. For those with a size disproportion, opposite side adjustment is always possible.

In more mature patients, these oncoplastic techniques may allow some individuals to avoid the radiation therapy that is a standard part of breast conservation therapy. Two large studies have shown no difference in long-term survival of suitably chosen patients after radiation therapy avoidance. Local recurrence is about 6% higher, but the better margins that can be achieved with oncoplastic techniques, may reduce this rate.

The second part of invasive breast cancer treatment, and the most important, is treatment of the whole body for potential micrometastases. This may be done before surgery, or after surgery, with no difference in outcome. The advantage of preoperative therapy for some patients is to reduce the size of the tumor, making a more conservative surgery possible. Preoperative treatment also permits a direct monitoring of tumor response, allowing a change in drug strategy if tumors don’t shrink, or even if they progress.

Treatment of the whole body, whether preoperative or postoperative, generally involves drugs that poison normal cell processes (chemotherapy), or drugs that modulate cell signaling (hormonal manipulation, anti-HER2 drugs). The choice of which drugs to use is a complex one, and depends upon the presence of certain receptors, like estrogen (ER) or progesterone (PR), or on the overexpression of signaling proteins like HER2.

Treatment also depends upon the intrinsic biology of the tumors. In the past this was assessed by microscopic appearance only. However, we now have gene expression assays that can provide prognostic information, such as risk of recurrence, accurate to a few percentage points. One assay, used actively in our practice, even provides information that predicts response to chemotherapy. More than two thirds of patients used to be recommended to receive chemotherapy. However, using these new gene expression assays, we now can avoid chemotherapy for nearly 80% of patients with tumors responsive to hormonal manipulation.

Cancer management with state-of-the-art surgery is just one part of today’s breast cancer treatment. Modern breast cancer care is complex. Having a practitioner early on who can function as a concierge, providing the latest objective unbiased advice is critical. Having them with you years down the road maximizes the benefit and the likelihood of success.