When you first receive a breast cancer diagnosis, there are things you need to know about what has determined your type of breast cancer. 

The first question to ask is “Is your cancer invasive or noninvasive?” The invasive nature (or lack thereof) identifies the cancer’s behavior. Noninvasive cancers are called “in situ.” Two noninvasive cancers are ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS). DCIS is a precancerous lesion and LCIS is cancerous; however, it does not evolve into the invasive cancer. Noninvasive cancers are identified as such because they remain local to their place of origin, and they have not spread beyond the duct or lobule into surrounding tissue. Invasive cancers, on the other hand, invade the tissues surrounding the membranes lining the duct or lobule. These are also able to travel to other areas throughout the body, including the lymph nodes, and these cancers are staged at I, II, I II, or IV. If cancer is staged at stage 0, it is noninvasive.

The next thing to ask is “Where in the breast did the cancer originate from?” Cancers usually originate in either the milk ducts, milk producing lobules, and connective tissues, although the latter is rare. Cancers that originate and connective tissues are called sarcomas. Milk ducts are usually affected by ductal carcinoma, which forms within the milk duct lining. The milk ducts are what transport breast milk to the nipple from the lobule where it is made. Milk producing lobules are usually affected by lobular carcinoma. Connective tissues are comprised of blood vessels, fat, and muscles.

The third question to ask is “What do your breast cancer cells look like under a microscope?” When analyzing cancer cells for the purpose of identification and grading, they compare the look of the cancerous cells with that of than noncancerous cells around it. It is important to remember that staging and grading are two different things. The way your cancer cells look underneath a microscope tell your doctor about your cancer so that he or she can determine your prognosis, the expectation of how your cells are likely to respond to treatment, and which course of treatment will likely be most effective. The degree to which cancer cells appear differently than the cells around them determines the cancers grade, which is based on a scale of 1 to 3. Cancers that are graded 3 are the most aggressive and look the most different from surrounding cells.

Another thing to ask is “Are hormones fueling your cancer cells?” Different cancer cells vary in their response to female hormones. Some will feed off estrogen and progesterone, while others are indifferent. Knowing the hormone receptor factor allows your doctor to identify a good course of treatment to kill the cancer and prevent recurrence. Hormone statuses are either estrogen receptor positive (ER), or just run receptor positive (PR), or hormone receptor negative (HR). If the cancer is receptive to hormones, the treatment will usually include some type of hormone blocker, and somewhat hormone receptors cancers opt for hysterectomy to stop production of the hormone altogether. Tamoxifen is the most popular hormone blocking medication, which can be taken to slow the growth of the cancer.

The final question to ask is “What is your cancer’s genetic makeup?” Knowing if your cancer is HER-2 positive will determine if it will be responsive to Herceptin. Also, other genetic information can help identifying the risk level of the cancer, which can allow women to have cancers that are considered low risk to avoid more aggressive treatments if desired. This test is not always done or recommended in all cases; however, it can be requested. When your doctor has genetic information about your cancer, they can be categorized into one of the few groups. Group 1, also known as luminal A, is inclusive of tumors that are hormone receptor positive but HER-2 negative. Group 1 cancers are expected to benefit from hormone therapy and chemotherapy. Group 2 cancers, also known as luminal B, is inclusive of cancers ER positive and HER-2 positive, but PR negative. These are expected to benefit from hormone therapy, chemotherapy, and Herceptin. Group 3 cancers are ER and PR negative, but HER-2 positive. These are expected to respond to chemotherapy and Herceptin. Group for cancers are basal-like and are considered triple negative, which means they are negative for ER, PR, and HER-2. These cancers are expected to benefit from chemotherapy.