Last updated on March 15, 2019
post updated 3/15/19
Adjuvant chemotherapy, what is it? This comprehensive post will break it down for you, with an easy to understand example included.
One of the most common questions I hear as a medical oncologist from my patients at an initial visit is:
“My surgeon told me she got all the cancer. So why am I here?”
A big part of what I do as a board-certified medical oncologist is to teach my patients that cancer is a systemic disease.
- Even though cancer started in one part of the body, there can be cancer cells in other places of the body, invisible at the time of surgery.
- Those cells can go undetected for months or even years before they cause a problem.
- Adjuvant therapies are treatments that come after surgery. They can decrease the chance that those cells will grow into new tumors, months — even years — later.
- In other words, adjuvant therapies lower the chance of developing metastatic cancer in the future.
First, some basic definitions:
- “Adjuvant” = any therapy given after surgery to increase the chance of being cured after surgery. Includes:
- chemotherapy
- radiation therapy
- endocrine (hormonal) therapy
- immunotherapy
- “Cure” = living out the rest of one’s life cancer-free, and dying of something other than cancer.
- (Note that this definition means we cannot ever say whether one is “cured.” Rather, we can estimate the likelihood one is cured.)
- “Metastases” = sites of cancer that grow outside of the initial origin of the cancer. This can be confusing.
- I like to explain to my patients that cancer is always “named” for the site of origin.
- One example is breast cancer. If breast cancer metastasizes, (or travels, spreads) to the bone, it is not “bone cancer.” It is breast cancer, metastatic to bone.
- How do we know this? Because if we do a biopsy, the pathologist identifies the cells under the microscope as breast cancer cells, not bone cancer cells.
- “Cancer-free” = the assumption that there is no remaining or active cancer in the body.
- “Remission” = the best clinical evidence suggests no evidence of remaining or active cancer in the body.
Confused yet? Let’s use a (hypothetical) example to try to make adjuvant therapy more clear.
- Ms. Smith is a 55-year-old woman who goes in for her yearly mammogram. An abnormality is found in her left breast. Fortunately, it is small, but a biopsy shows it is cancerous.
- She is referred to a surgeon, who explains to her two options for surgery.
- Mastectomy (removal of the entire breast tissue)
- Breast-conserving surgery, also called “lumpectomy” (removal of only the tumor and a small portion of the breast surrounding it).
- Mrs. Smith wants to preserve her breast. But she is afraid that if she does not have mastectomy, she will have a lesser chance of cure.
- Her surgeon explains that if she chooses lumpectomy, it will be recommended to have adjuvant radiation therapy afterward. Her surgeon tells her that she has the same chance of cure with either lumpectomy and radiation, or mastectomy.
Huh? Ms. Smith is confused.
Let’s break it down:
-
Over several decades, more aggressive, extensive, and disfiguring breast surgeries did not impact the long-term cure rates for breast cancer.
- Even women who had extensive removal of tissue under and around the breast, including muscle –“radical” mastectomy — could have metastatic recurrences of breast cancer months to years later.
- Ultimately, surgeons realized that breast cancer is not just a disease of the breast.
- If breast cancer cells have metastasized, or ‘escaped’, into the body, before the surgery, it does not matter how extensive the mastectomy is. The cancer can recur months to years later. Those cells can hide in other tissues (such as bone, bone marrow, liver) and grow new tumors months to years later.
- (For an elegant in-depth discussion of the history and evolution of breast cancer surgeries, I recommend the book “The Emperor of All Maladies,” by Siddhartha Mukherjee. Don’t be put off by the size of the book, it is highly readable. It was also made into a documentary series by PBS).
-
Once this reality gained widespread acceptance, surgeons instead turned to doing SMALLER surgeries.
- To summarize many decades of research, the current standard of care is that a lumpectomy need only remove enough tissue to show that there are no cancer cells at the margin (the edge of the tissue that has been removed). This is determined under the microscope by the pathologist, who analyzes the tissue that has been removed.
- If paired with adjuvant radiation therapy, lumpectomy with clear margins has equal long-term survival rates as mastectomy.
- Please note, this is key, paired with radiation. I sometimes meet patients who choose a lumpectomy, but then tell me afterward they are not going to do the radiation.
- I tell my patients, if you choose lumpectomy, that means you are choosing up-front to have adjuvant radiation. They go together.
- (one possible exception would be a woman over age 70 with a small tumor with no high-risk features. But that is a discussion that needs to happen between the woman and her surgeon, radiation oncologist, and medical oncologist).
Whether Mrs. Smith chooses mastectomy, or lumpectomy with radiation, she will need to meet with a medical oncologist after surgery. This consultation will help estimate her risk of future recurrence, and whether she would benefit adjuvant medical therapies.
Let’s continue the story to illustrate this better:
Ms. Smith is relieved by the information and chooses lumpectomy with adjuvant radiation therapy.
(Not all breast cancer qualifies for lumpectomy – this should always be a discussion between a woman and her surgeon. Some factors that can disqualify a woman from being a candidate from lumpectomy can include (and are not limited to) a very large tumor, and/or more than one tumor in the same breast).
Ms. Smith does well with lumpectomy surgery. At her post-op visit, her surgeon explains that she “got it all” and the “lymph nodes are clear.”
Ms. Smith is relieved and prepares herself for the next step of her post-lumpectomy radiation.
She is then alarmed and confused when her surgeon sets up a consultation with a medical oncologist.
The first thing she then says to the medical oncologist is, “My surgeon said she got it all, so I don’t even know why I’m here.”
Here’s what I tell my patients. Studies show:
- Breast cancer, like most all cancers, is tricky.
- Cancer can be sneaky.
- Even small tumors, not in the lymph nodes, (stage I), have a small risk of recurrence over time.
- For hormonally sensitive breast cancer (often referred to as “ER-positive”, ER = estrogen receptor), this risk persists for life. (A recent NEJM meta-analysis of over 60,000 women with breast cancer sheds more evidence on this).
- (I do not tell people this to frighten them, but to empower them to make the best medical decisions for themselves).
- Taking a pill medication with overall low rate of side effects, once per day for the next 5 years, will lower the risk of breast cancer recurrence by ~50%. It will also lower the risk of death from breast cancer by ~30%.
- However, it is not a guarantee. Unfortunately a small number of women will still relapse, and even die from breast cancer, despite taking the anti-estrogen pill.
Our job as medical oncologists is to advise our patients if they are in a high enough risk group of that happening.
So that additional treatment with chemotherapy after surgery (adjuvant chemotherapy) would be “worth it” to lower their risk (i.e. the potential life-saving benefits outweigh the potential risks).
Historically, the main predictors of risk of relapse and metastases were anatomic – the size of the tumor and whether or not there are cancer cells in the lymph nodes.
More and more we have learned that the risk is not always tied to anatomic features. Sometimes cancers can be small in size, but aggressive in behaviour.
It is our job as medical oncologists to analyze and interpret the findings of the pathology report to advise our patients.
Ms. Smith is relieved to learn her risk of recurrence is overall low, but worried to hear that the risk is not zero.
She wants to know why there isn’t a scan or blood test that could be done to determine if she needs adjuvant chemotherapy.
This is a great question, and there is quite a bit of research working on a reliable blood test, but that is likely still years away from being validated for every-day practice.
In the meantime we do have some risk-stratifying tests that can be run on the tumor tissue. (This topic is beyond the scope of this post – I think I’ll have to devote another post just to this topic in detail).
We, as medical oncologists, are trained to know when to advise our patients when those tests should be done.
But as for imaging scans, they will not help us with this up-front decision. We are talking about treating microscopic cancer cells — not possible to see on CT scans or PET scans.
(or MRI, or ultrasound, or any other imaging test…)
Ms. Smith and her medical oncologist review her results together.
Her breast cancer is in a low enough risk group that she would not necessarily benefit from adjuvant chemotherapy.
She proceeds to her radiation therapy treatments.
When they are completed, she will return to her medical oncologist to start her endocrine adjuvant therapy (the anti-estrogen pill).
While this example focused on breast cancer, medical oncologists have these same professional discussions every day with people with all types of cancer.
For each person, we use the available clinical data to make a risk assessment.
We also take into account each person’s age, health, level of function, living situation, goals, and support system, before making a recommendation.
This is what we mean when we say we individualize the cancer care.
Expect your initial medical oncology visit to last 45-60 minutes (or even longer), and believe that your oncologist has spent already that same amount of time, or more, analyzing your case, and talking with your surgeon.
There’s a lot of “behind the scenes” work that we do before we even meet you.
If you are frightened to meet with a medical oncologist, I hope this article will help change your mind.
Or at the least, to go into the appointment with an open mind.
Even if it is not the news you want to hear, if your medical oncologist recommends adjuvant treatments, s/he is doing so with your best long-term interests in mind.
To give you the best chance of cure.
Disclaimer: This is by no means an exhaustive coverage of this topic (which would be impossible to do in under 1800 words), nor is this meant in any way to be used as medical advice. Please see full site disclaimers on the about me page.