Chemotherapy starts to work as soon as it gets inside cancer cells. Chemotherapy drug levels peak in the blood soon after the infusion, are taken up by tissues and cells, and then fall to undetectable levels as the drug is metabolized and eliminated from the body. The drug will have been completely eliminated from your body by the time the next infusion is given; this insures that drug levels do not build up with each infusion, otherwise there may be too much toxicity. Because the chemotherapy is not in the blood for very long, and not all cancer cells may take up the chemotherapy or be sensitive to the chemotherapy at all times, chemotherapy has to be given for multiple cycles.

Hormonal therapies such as aromatase inhibitors and faslodex, can take a few months to build up in the body, so they can take longer to start working.

Here are some good links from ASCO regarding current state-of-the-art thinking regarding breast cancer patients' followup (http://bit.ly/Q7NcT6,http://bit.ly/MVYae5). Some highlights of the summary include seeing the doctor routinely at increasing intervals, seeing a gynecologist routinely whilst taking tamoxifen (if the patient has a uterus/not had a hysterectomy), and *not* routinely ordering blood work tumor markers and imaging tests other than mammograms. These are ASCO-specific guidelines; deviations away from these guidelines are not necessarily good or bad and must be considered on a case-by-case basis. Many large cancer centers have "breast survivorship clinics" where breast cancer survivors have specially tailored medical and psychosocial programs at their disposal, for example. This area of oncology, like may other areas, still generates some controversy. For example, there has actually been a scientific trial looking at outcomes of early-stage breast cancer patients followed long-term by oncology specialists or family physicians (http://bit.ly/T19RRG)... no differences were found between the two groups. However, that said, most oncologists of which I'm aware (me included) prefer to see their patients long-term after treatment. Yet if a patient was motivated to integrate her long-term oncologic care with her primary care physician (PCP), and the oncologist discusses her case with her PCP, there is sufficient evidence available that this, too, is a valid form of survivorship care.

Chemotherapy is often recommended for stage 1 cancers if the cancer is ER negative or Her2/neu positive. In the absence of adverse features such as high nuclear grade or lymphovascular invasion, cancers that are ER positive and Her2/neu negative may be treated with hormonal therapy alone, and may not need chemotherapy. The Oncotype 21 gene assay is a molecular test that is often performed for stage 1 ER positive Her2/neu negative cancers. The test has been a valuable tool to help determine whether the addition of chemotherapy to hormonal therapy would be of benefit for a particular individual.

When we speak of “lines” of chemotherapy we are referring to the practice of giving sequential regimens of chemotherapy to patients with metastatic disease. The list of FDA approved drugs for breast cancer includes more than 20 drugs. There is no “typical” or “standard” first line therapy. Factors that are taken into consideration when choosing a first line treatment include whether the cancer is ER or Her2/neu positive, whether a patient is symptomatic or not, what the extent of the cancer is, and which chemotherapy drugs the patient may have been exposed to in the adjuvant setting. Quality of life issues, such as whether the treatment will cause hair loss, and how frequently the patient has to come into the doctors’ office to get an infusion are important considerations. Some common chemotherapy drugs used in the first line setting are paclitaxel, docetaxel, and capecitabine.

Affinitor (everolimus) is a new class of drugs that was recently approved to be used in combination with exemestane, an aromatase inhibitor. Everolimus blocks a pathway related to cancer cell growth (the PI3K pathway). Studies in the laboratory suggested that this pathway is one of the reasons why ER positive cancer cells may develop resistance to hormonal therapy. In women whose cancers had previously progressed on either letrozole or anastrazole aromatase inhibitors, adding everolimus to exemestane was shown to be more effective than exemestane alone. This is the first time that a drug has been approved that appears to “re-sensitize” cancer cells to hormonal therapy, and that is an important milestone for the treatment of hormone receptor positive breast cancer.

On the first visit the oncologist will make a recommendation for adjuvant therapy. This recommendation is based on a review of the pathology report, together with considerations such as a patient’s age and overall medical health. During the first visit the oncologist usually discusses the expected benefits of the therapy (e.g. chemotherapy, hormonal therapy), as well as the potential side effects. To prepare for the visit, a patient should be aware of past and current medical problems, and have a list of current medications. It is also good idea to write down any questions you may want to ask the oncologist.

A breast cancer patient may see the oncologist at any time after her diagnosis, but most commonly the meeting occurs after the patient’s surgery, when the pathology report is available. Alternatively, in cases where the surgeon thinks the patient may benefit from preoperative chemotherapy, the surgeon will refer the patient to the medical oncologist prior to the definitive surgery. Finally some patients may seek out a medical oncologist earlier in the process in order to discuss a “big picture” view of her breast cancer treatment.

Breast cancer is not just one disease. Using molecular studies, breast cancer can be divided into 4 subtypes, each with a different natural history, prognosis, and treatment.

Our own research suggests that some subtypes occur more frequently in particular Asian ethnic groups. In our study, Japanese patients were more likely to have the Luminal A subtype, which often responds to hormonal therapy, whereas Filipino patients were more likely to have the Her2/neu subtype, which often requires treatment with chemotherapy and trastuzumab (Herceptin). We don’t know why these differences exist, and this is an area of research we are exploring.