Breast Cancer Treatment & Screening Advancements
- Women with HER2-positive breast cancer may be able to find hope in a new drug called ENHERTU; some breast oncologists tell us the drug could be "practice-changing" for HER2 patients.
- Hope is on the horizon for early-stage triple-negative breast cancer patients as immunotherapy has been approved to treat this type of cancer in addition to chemotherapy.
- PARP inhibitor drugs were developed for women whose cancers are a result of the BRCA mutation; the drug olaparib (brand name: Lynparza) has been shown to significantly reduce a woman's risk of breast cancer recurrence and prevent the cancer from spreading in HER2-negative, high-risk patients with the BRCA1 or BRCA2 genetic mutation.
- New three-dimensional mammogram technology is detecting more breast cancers and returning fewer false positives than its two-dimensional counterpart.
"For women who've been diagnosed with breast cancer, the advancements of the last year represent increased options," Dr. Elizabeth Comen, a medical oncologist at Memorial Sloan Kettering Cancer Center, tells SurvivorNet. "As you learn very quickly when you're diagnosed, breast cancer is actually many different diseases depending on the hormones driving your cancer and the molecular and genetic makeup of your specific disease. Despite the pandemic, there have still been considerable advances in breast cancer in the past two years."
Read MoreENHERTU: Treating Metastatic HER2-Positive Breast Cancer
For women (or men) diagnosed with HER2-positive breast cancer, it means they have high overexpression of HER2 (human epidermal growth factor 2) on their cancer cells. If you have metastatic HER2-positive breast cancer, it means your breast cancer overexpresses HER2 and has spread beyond the breast to other parts of your body. HER2-positive breast cancers were previously thought to confer worse prognosis, but targeted agents have become available that are changing the landscape of how HER2-positive breast cancer is treated.
HER2-Positive Metastatic Breast Cancer Treatment Options Explained
Women with metastatic or unresectable HER2-positive breast cancer can potentially find hope in a new drug called ENHERTU, or trastuzumab deruxtecan; some breast oncologists tell us the drug could be "practice-changing" for HER2 patients.
In mid-September, preliminary results from a recent study about the drug's effectiveness were released at the European Society for Medical Oncology Congress 2021, a renowned European oncological conference. The results were "quite dramatic," Dr. Douglas Marks, a medical oncologist at NYU Langone Health, tells SurvivorNet. ENHERTU is reducing the risk of disease progression or death by 72% when administered as a second-line treatment; this is compared to the drug Kadcyla, or T-DM1 (trastuzumab emtansine).
T-DM1 is the current standard of care drug for HER2-positive metastatic breast cancer patients who have already gone through first-line treatment. The trial, which enrolled 524 patients in Asia, Europe, North America, Oceania and South America, is still ongoing, but these early results have shown a very promising future for ENHERTU.
The phase 3 trial also found that people treated with ENHERTU had about a three-fold improvement in progression-free survival (the time someone lives with a disease without it progressing) than patients treated with Kadcyla.
"The results were really incredible when looking at patients with second-line treatment," Dr. Marks tells SurvivorNet of this ground-breaking drug trial. He adds, "I believe (the drug) will be practice-changing."
Keytruda: Treating Early-Stage Triple-Negative Breast Cancer
Triple-negative breast cancer accounts for between 10% to 15% of all breast cancers, and it has historically been one of the most aggressive and hardest to treat forms of breast cancer. This is because it lacks each of the main breast cancer drivers estrogen receptor, progesterone receptor and HER2 receptor. Triple-negative doesn't respond to treatments that target these receptors, so not having these receptors will affect your treatment.
The First Immunotherapy Approved For Breast Cancer Hope For Triple Negative Breast Cancer
This limited choice in treatment means that the best way oncologists can treat this type of breast cancer for most patients is with chemotherapy, Dr. Comen says. But, hope is on the horizon as immunotherapy has been approved to treat early-stage triple-negative breast cancer in addition to chemotherapy. (If you have early-stage disease, that means the cancer hasn’t spread beyond your breast or potentially beyond the lymph nodes in your armpit.)
Immunotherapy works by boosting your body's own immune response to help kill the cancer and stop it from spreading. Over the summer, the U.S. Food and Drug Administration approved pembrolizumab (or Keytruda, its brand name) for early-stage triple-negative breast cancer to be administered in combination with chemotherapy as neoadjuvant therapy (before surgery), then continued as a treatment on its own after surgery. This treatment regimen alone extended event-free survival in patients with early-stage triple-negative breast cancer. (Keytruda is already used to treat other types of cancer, including melanoma and non-small cell lung cancer.)
For patients with stage 2 or stage 3 triple-negative breast cancer, adding pembrolizumab in combination with chemotherapy before surgery increases the chance of living breast cancer-free, Dr. Sylvia Adams, director of the Breast Cancer Center at NYU Langone’s Perlmutter Cancer Center, previously told SurvivorNet. She was one of several researchers involved with the trial. (Note: This is without pembrolizumab being used as a treatment on its own after surgery.)
"This really has been practice-changing because there's a really particular chemotherapy regimen that these patients (triple-negative breast cancer patients) get (for treatment)," Dr. Sarah Cate, a surgical breast oncologist at Mount Sinai, tells SurvivorNet.
Dr. Marks reiterated Dr. Cate's point: "This (drug approval) is also practice-changing. (Triple-negative breast cancer) is a very difficult breast cancer to treat," he says, adding that the median survival rate for this type of breast cancer is about two years.
PARP Inhibitors: Treatment for Women with BRCA Gene
"One of the other major advances of the last year is the new data about something called PARP inhibitors," Dr. Comen tells SurvivorNet.
PARP Inhibitors Provide New Promise for Certain Metastatic Breast Cancers
PARP inhibitor drugs were developed for women whose cancers are a result of the BRCA mutation, Dr. Comen says. The BRCA1 (BReast CAncer 1) or BRCA2 (BReast CAncer 2) genes help cells repair their DNA damage. Having a change, or mutation, in one of these genes increases a woman's risk of getting breast cancer. These gene mutations are commonly passed down in families; if a parent carries a BRCA gene mutation, there's a 50-50 chance you could be carrying it as well.
"PARP inhibitors leverage this repair defect in BRCA-associated cancers and stops the cancer cell from replicating," Dr. Comen says.
In June, a new study (called the OlympiA trial) was published in The New England Journal of Medicine. The study showed that using one of these PARP inhibitor drugs called olaparib (brand name: Lynparza) following surgery and/or chemotherapy significantly reduced a woman's risk of breast cancer recurrence and prevented the cancer from spreading in HER2-negative, high-risk patients with the BRCA1 or BRCA2 genetic mutation.
The trial included 1,836 patients from 420 centers across 23 countries, and generated impressive results. The three-year survival rate without a recurrence of what's called invasive breast cancer was 85.9% for patients treated with olaparib, compared to 77.1% in the placebo group.
"These results are practice-changing because it changes the way we treat some women who have these BRCA mutations."
3-D Mammograms: Detecting Breast Cancer Earlier
In order to catch breast cancer early, the typical go-to method for breast oncologists is the mammogram. Odds are, if you're a woman over the age of 40, you've had a mammogram before. A mammogram is a two-dimensional picture of the breast.
When Should I Get a Mammogram?
"However, there's a new modality called tomosynthesis, which is a three-dimensional mammography," Dr. Jesus Anampa, a medical oncologist at Montefiore Medical Center, tells SurvivorNet. And this new technology is detecting more breast cancers and returning fewer false positives than its two-dimensional counterpart, according to research published March 10, 2020, by the journal Radiology.
The 3-D mammogram takes an image of the entire breast with X-rays, "so you can have a better look of areas that may have (been) hidden with a two-dimensional, standard mammogram," Dr. Anampa says.
However, dense breast tissue makes it more difficult to interpret a mammogram, since cancer and dense breast tissue both appear white on a mammogram. According to the U.S. Centers for Disease Control and Prevention, women with dense breasts have a higher risk of getting breast cancer. NCI reports that about half of all women aged 40 and older who get mammograms are found to have dense breast tissue.
For women with dense breast tissue, an MRI or 3-D mammogram is often recommended over a traditional, 2-D mammogram. But the United States Preventive Services Task Force reports that the effectiveness of other screening tests such as ultrasound or MRI for women with dense breasts is “not yet clear.”
The FDA reports that another benefit of 3-D mammograms is that these screening tests are more accurate than traditional mammography in “pinpointing the size and location of cancer tumors in dense breast tissue,” says Kyle Myers, director of imaging and applied mathematics at the FDA. With 3-D breast tomosynthesis, according to the FDA, doctors can detect abnormalities earlier and better see small tumors because the images are clearer and have greater contrast, as Dr. Anampa also tells SurvivorNet.
Some three-dimensional mammogram technology has already been approved by the FDA, however, the National Cancer Institute is currently conducting TMIST, also known as the Tomosynthesis Mammographic Imaging Screening Trial.
This is a randomized breast screening trial that aims to help researchers learn about the best ways to detect breast cancer in women with no symptoms. The trial compares the two-dimensional and three-dimensional mammogram technology; the goal of screening for breast cancer is to find breast cancer early when it can be treated easier. But according to NCI, "researchers are doing this trial because they don't know if 3-D is better than 2-D mammography for breast cancer screening."
The study is ongoing and is expected to grow in the next year or so, Dr. Anampa says. Right now, the trial is taking place in mammography clinics across the United States, with a few sites in Canada and Argentina, according to NCI. Eventually, there will be more than 100 clinics taking part in the trial. "However, because the results will take longer to come up, it's going to take a few years before we have results," Dr. Anampa adds. The results will tell doctors what’s more effective: the 2-D mammogram or the 3-D mammogram.
"That's exciting because as I said, for the past year, the main screening method has been a two-dimensional mammogram. So, these (three-dimensional mammograms) will open a new door," Dr. Anampa says.
Contributing: Alison Maxwell and Abby Seaberg
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