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What Kind of Cancer Do I have?

This question might be answered in different ways. It seems that most women who ask this question are wanting to know if their cancer is one that “spreads like wildfire”, or one that can be cured with treatment. They want to know how aggressive their cancer is. When doctors talk about the kind of cancer someone has, they are usually talking about where the cancer originated, and whether there is any indication of spread to other organs.

I have found an analogy helpful to describe to women this concept of what kind of cancer they have. It’s kind of like a boxer who will be going into the ring to fight an unknown opponent, and wants to know what to expect when he walks in that ring. The unknown opponent in this example is like your cancer—you want to know if you’re going to be able to knock him out, or if the fight might go 15 rounds. You may have heard that they have a wicked left jab. Someone else might say that he is really quick on his feet. Someone else may know that he tires out in the later rounds. Now these details may make you feel better or worse about your odds in the ring, but they aren’t the most important. And none of these individual details are going to let you know in advance whether you are going to win the match. But each detail may add to your ability to prepare for the fight. It’s the same with breast cancer, and all the different details we can measure. Probably the most important things to know about the boxer would be his height and weight. For breast cancer, the most important things are the size of the cancer and whether there is cancer in the lymph nodes.

So let’s walk through this step by step. I will start by showing a table of the most important tests that are likely to be done to evaluate your cancer, and then give a more detailed description of each one.

Probably the best summary of how to say what kind of cancer you have is to put the information in this form:

Invasive or Non-Invasive

Ductal or Lobular

Clinical or Pathologic Stage 0, 1, 2, 3 or 4

Grade 1, 2 or 3

ER positive or negative

HER2 positive or negative

If you can already circle one term on each line above, then you and your doctor have a very good description of your cancer, and can make informed decisions about how best to treat it. Other tests may play a role, but primarily on a tailored individualized basis. Scroll below this table for more detailed information.

Tests and categories to define what kind of cancer you have Description How is the result used
Tumor size Measured in centimeters, with ranges of :no invasion (T0),0-2 cm (T1),2-5 cm(T2),

and >5 cm (T3),

or more advanced based on type of spread (T4)

The stage of the cancer is based in part on tumor size, with stages ranging from 0-4. This is the “T” in TNM staging
Any tumor found in the lymph nodes? Measured as positive or negative, or 0, 1-3, >3 The stage of the cancer is based in part on lymph node status, with stages ranging from 0-4. This is the “N” in TNM staging
Any tumor seen elsewhere (metastatic disease), for example in the lungs, bones, liver, or brain? Measured as “yes” (M1) or “no” (M0) The stage of the cancer is based in part on the presence or absence of cancer elsewhere (metastases), with stages ranging from 0-4. This is the “M” in TNM staging.
Grade 1,2, or 3 Grade 3 is more aggressive, though this factor is of slightly less significance than the cancer stage.
Estrogen receptor (ER) Usually measured as a percentage, 0-100%.  “Positive” is defined differently by various labs, as >1%, >5%, or >10%. If ER positive, treatment that either blocks estrogen, or decreases its production is likely to be effective in decreasing risk of recurrence.
Progesterone receptor (PR) Usually measured as a percentage, 0-100%.  “Positive” is defined differently by various labs, as >1%, >5%, or >10%. If positive, prognosis is better, though specific targeted treatment options are not available.
HER2, or HER-2-neu Two different ways to measure, either by measuring the actual amount of the protein receptor (HercepTest), or by measuring if there are extra copies of the gene that produces the protein (FISH). For HercepTest, “negative” is defined as 0, or 1+. “Positive” is defined as 3+. A 2+ result is considered equivocal, and in these cases, the other (FISH) test is usually ordered to decide if positive or negative.FISH “negative” is defined as 1-1.8, “positive” is defined as >2.2, and 1.8-2.2 is also considered equivocal. If positive, the cancer is considered more aggressive, but a specific targeted treatment (Herceptin) is available, and is routinely used except perhaps in very small localized tumors.
Ki-67 Given as a percentage from 0-99%, corresponding to the “proliferative” ability of the cancer cells. Higher percentage implies a more aggressive cancer, but has less significance than cancer stage.
OncoTypeDX Recurrence Score Result is a number from 1-99, and then categorized as Low (1-18), Intermediate (18-31), or High (>31).  This test is only used in cancers which are estrogen receptor (ER) positive. If Recurrence Score is low, then there is no benefit from taking chemotherapy. If Recurrence Score is high, there a BIG advantage to taking chemotherapy. If Recurrence Score is Intermediate, there may be an advantage for chemotherapy, but we don’t yet know for sure.

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If you have had a biopsy of a lump in your breast, or a biopsy done because of something seen on mammogram, and the biopsy showed cancer cells, then you almost certainly have a cancer that began in the breast. Although there are exceptions, most of these will be “breast cancer”. The pathologist almost always will be able to further classify the cells as being either of “ductal” or “lobular” origin, but both of these are still breast cancer. He will be able to see whether there is any invasion into the surrounding tissue or not. If there is no invasion, it will be called “in situ” or “non-invasive”. These cases are especially favorable, because it’s like finding seeds which haven’t yet sprouted, and surgical treatment is basically a cure. For more information, follow this link to DCIS.

Your doctor will make an estimate about the size of the cancer based on the available information at the time of biopsy. If it is an actual lump, an estimate of its size can be made just by feeling it (palpation). Such cancers can usually be seen with an ultrasound machine, and if so, a more accurate measurement can usually be made this way. If your cancer was found because of calcifications on a mammogram, the size is usually harder to estimate before surgery, though these usually are quite small if they cannot be felt, so that’s usually a good sign. Your doctor should also check to see if any lymph nodes can be felt under your arm, and if so, this could be an indication that some cancer cells have already had a chance to spread from the breast itself. An ultrasound machine can also be used to evaluate the lymph nodes, and abnormal nodes may be seen even if they cannot be felt. If necessary, a biopsy of the lymph nodes can be done with a needle, usually with the aid of an ultrasound in order to precisely position the needle in the node.

The pathologist can provide an estimate of the aggressiveness of the cancer based on how abnormal in appearance the cancer cells are. This is called “grading” the cancer. The grade can be either 1, 2, or 3. The Grade 3 cancers are considered to be the more aggressive type. These cancer cells are more bizarre in appearance, and show evidence of dividing more rapidly, compared to the Grade 1 cancers.

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There are some additional tests routinely ordered for evaluating breast cancer cells, but these usually take a week or so to be completed. The cells can be analyzed to see if there is any sensitivity to hormones, specifically estrogen and progesterone, the two most significant female hormones. Another test checks to see if there is extra production of a protein called HER2. This protein is involved in the growth of breast cancer cells, and patients with “HER2 positive” cancers are more likely to have recurrence or spread of their cancer. Although the prognosis is poorer for these HER2 + patients as a group, we now have two HER2 specific chemotherapy drugs (Herceptin, or trastuzamab, and Perjeta, or pertuzamab) that specifically target the HER2 receptor protein, and are highly effective in such cases.

Another exciting new test can be used for cancers that are specifically estrogen receptor (ER) positive. The test is called the OncotypeDX Recurrence Score. This test takes about 2 weeks to get a result. All tests are done at a central lab in California. This test should only be ordered if the result is going to be used in deciding on the use of chemotherapy. You can find out more about this test by following this link.

These are not the only tests available for analyzing your breast cancer, but these are the most important ones. There is no doubt that ongoing research will find new tests which will help in deciding on the best treatment. It is hoped that, just as Herceptin and Perjeta specifically target HER2, and tamoxifen targets the estrogen receptor, we may find other specific cancer proteins which can be targeted with specifically designed antibody drugs.

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