Renewed Hope for Metastatic Breast Cancer

Breast Cancer Awareness Month

October marks National Breast Cancer Month. Breast cancer awareness is an integral component to women’s health management and care, as it is the most common cancer in women worldwide. It is also the principal cause of death from cancer among women globally.

In the U.S, there are roughly 155,000 facing metastatic breast cancer (MBC) who take into stride daily health hurdles associated with their diagnoses.

October 13 is Metastatic Breast Cancer (MBC) Awareness Day, and your Capital Women’s Care team discusses breast cancer subtypes and encouraging treatment studies offering renewed hope and opportunity to achieve quality health and increased longevity for those diagnosed with MBC.

What is MBC?

Metastatic Breast Cancer (MBC), known also as Stage IV, spreads beyond breast tissue to other organs within the body, including bones, liver, lungs or brain through a process known as “metastasis,” causing breast cancer to become a deadly disease.

Even though MBC invades other organs it is still considered breast cancer, as tumor cells remain similar in structure and behavior to those tumor cells found within breast tissue.

A recent survey found that

  • more than 60% of respondents said they know little to nothing about metastatic breast cancer
  • 72% believe breast cancer in advanced stages is curable if diagnosed early
  • 50% believe breast cancer progresses because patients either didn’t take the right medicines or preventive measures.

It’s important to note that anyone diagnosed with earlier stages of breast cancer can experience metastatic recurrence. Some have MBC during first diagnosis, even with implementation of mammograms and early detection practices within their personal breast healthcare plan. About 20% to 30% of patients with early stage cancer have it return, even if told early stage cancer was “cured.” Another 8% of new breast cancer cases are deemed metastatic during initial diagnosis. MBC can occur 5, 10 or 15+ years after original diagnosis and successful treatment.

MBC differs from early stage breast cancer in that MBC is treatable but is no longer curable. Treatment for MBC becomes lifelong, focusing on preventing cancer spread and managing symptoms utilizing palliative care focused on addressing side effects, stress and pain, to provide good quality of life as long as possible.

As researchers delve further into MBC, those diagnosed can now live longer, quality lives. New innovative treatments to stop disease progression and further scientific research into new therapies and studies monitoring breast cancer growth behaviors are extending the lives of those diagnosed with MBC.

Breast Cancer Subtypes

Breast cancer treatment can become complicated due to the different breast cancer subtypes and individual responses to implemented therapies and treatment.  There are 5 main intrinsic or molecular subtypes of breast cancer that are based on the genes which the cancer expresses:

Luminal A breast cancer -- a hormone-receptor positive (estrogen-receptor and/or progesterone-receptor positive), HER2 negative, and has low levels of the protein Ki-67, which helps control how fast cancer cells grow.

Luminal A cancers are low-grade, tend to grow slowly and offer the best prognosis. Luminal A tumors are associated with the most favorable prognosis in part because they are usually responsive to hormonal therapy.

Luminal B breast cancer -– a hormone-receptor positive (estrogen-receptor and/or progesterone-receptor positive), and either HER2 positive or HER2 negative with high levels of Ki-67, an indicator of vast quantity of actively dividing cells.

Luminal B cancers generally grow slightly faster than luminal A cancers with a slightly worse prognosis.

HER2-positive breast cancer -- a common form, it affects about 1 in 5 women diagnosed with breast cancer. These tumors produce higher levels of HER2 protein, which covers the outside of breast cells.

If early detection takes place, HER2-positive cancers are amenable to varying drug treatments, but these tumors tend to progress faster than other types of breast cancers. Metastatic disease poses treatment challenges because patients oftentimes develop resistance to treatment medication.

This cancer subgroup is hormone-receptor negative (estrogen-receptor and progesterone-receptor negative) and HER2 positive. HER2-enriched cancers tend to grow faster than luminal cancers and can have worse prognosis, but they are often successfully treated with targeted therapies aimed at the HER2 protein.

Triple-negative (Basal-Like) breast cancer -- an aggressive subtype that accounts for about 10% to 20% of all breast cancer cases. It has proved to be resistant to many standard treatments.

Typically, early-stage triple-negative breast cancer is treated with chemotherapy, with about 40% to 50% effectiveness in garnering complete response to treatment, having no evidence of disease afterward.

It is hormone-receptor negative (estrogen-receptor and progesterone-receptor negative) and HER2 negative.

This type of cancer is more common in women with BRCA1 gene mutations. It is also is more common among younger premenopausal and Black women.

Normal-like breast cancer –- is similar in structure to luminal A disease: hormone-receptor positive (estrogen-receptor and/or progesterone-receptor positive), HER2 negative, and has low levels of the protein Ki-67, which helps control how fast cancer cells grow.

While normal-like breast cancer offers good prognosis, its slightly worse than prognosis associated with luminal A cancer.

Those breast cancers with a faster growing rate characteristic are more likely to metastasize.

Early detection through vigilant, recommended breast cancer screening schedules and a comprehensive, individualized breast healthcare plan are the best foundations for monitoring disease potential and offering greatest chances for positive breast cancer prognoses should disease become present.

Renewed Hope

Several recent studies highlighted at the San Antonio Breast Cancer Symposium in December 2019 indicate new breast cancer treatment options and therapies are on the horizon:

The immunotherapy drug pembrolizumab can benefit some patients with triple-negative breast cancer when given with chemotherapy before surgery and as part of post-operative treatment regimen, according to the KEYNOTE-522 trial.

The study involves immunotherapy, one of the most exciting cancer advances of the past decade, applied to one of the worst breast cancer types. Triple-negative breast cancer is an aggressive subtype with proven resistance to many standard treatments.

Previously reported data indicated those receiving pembrolizumab plus chemotherapy had higher rates of complete response compared with those receiving chemotherapy alone:  64.8% compared with 51.2% after a median of 15.5 months of follow-up.
The latest data from the trial show that among those with cancer spread to the lymph nodes, 64.8% of those receiving the drug plus chemotherapy had a complete response compared with 44.1% of those receiving chemotherapy only.

Immunotherapy drugs have only recently been tested on breast cancer. They have been proven successful in treatment of lung cancer, melanoma and other cancers. Typically, early-stage triple negative breast cancer is treated with chemotherapy.

Decitabine, a drug used to treat a blood and bone marrow cancer, may play an important role in treating triple-negative breast cancer, suggests a study conducted by Mayo Clinic researchers.

Published in April 2018 in the Journal of Clinical Investigation, researchers observed decitabine helped inhibit additional cancer growth and was effective in treating chemotherapy-resistant tumors, which significantly increase recurrent breast cancer risk and death. The Food and Drug Administration (FDA) approved decitabine for treating myelodysplastic syndromes affecting bone marrow and blood.

Additional advances in treating women with metastatic, HER2-positive disease were also presented:

The first study, published simultaneously in The New England Journal of Medicine, provides a potentially life-extending option for those with HER2-positive in whom cancer has developed resistance to the standard medication.

The study included 253 patients with metastatic HER2-positive breast cancer who were previously treated with the drug T-DM1 or trastuzumab emtansine and other HER2-targeted medication, such as trastuzumab and pertuzumab. Patients received 6 prior treatments for advanced cancer on average.

Within the study group, 184 patients received investigational medication trastuzumab deruxtecan, (T-Dxd.) It features a monoclonal antibody, a lab-made antibody, designed to target HER2 protein found on cancer cells. It also delivers a topoisomerase 1 inhibitor to attack cancer cells. The payload drug is about 10 times more potent than similar drugs in its class and has typically not been previously used to treat breast cancer.

The study showed 60.9% response rate in those receiving T-Dxd. Six percent had complete response to treatment, meaning no evidence of disease. Just under 55% had partial responses to treatment, meaning decrease in size and extent of tumor occurred.

The median progression-free survival time, the time during which tumor did not grow due to the medication, was 16.4 months.

This data indicates the best response yet seen in patients with metastatic HER2-positive breast cancer who have been heavily pretreated. The 16-month median survival indicates nearly double or triple compared with typical studies in this population, where median survival is 4 to 5 months. The data was deemed compelling due to the initiation of T-Dxd to a heavily pretreated population, who comprise facing the latter stages of metastatic disease. In general, drugs used within the early setting for metastatic disease are found to be more effective.

A second study indicates adding pertuzumab to trastuzumab plus chemotherapy reduces cancer recurrence.

Follow-up data from the phase 3 APHINITY trial showed adding pertuzumab to trastuzumab plus chemotherapy after surgery reduces risk of cancer recurrence in women diagnosed with HER2-positive breast cancer.

The addition of the HER2 inhibitor drug trastuzumab to chemotherapy as a first-line treatment for HER2-positive, early-stage breast cancer cures many patients, yet some still experience disease recurrence, said study lead author and scientific director at the Institut Jules Bordet in Brussels.

The APHINITY trial was designed to evaluate a different HER2 inhibitor, pertuzumab, to lower recurrence risk. The study compared pertuzumab added to chemotherapy plus trastuzumab, with placebo added to chemotherapy plus trastuzumab, in patients with early HER2-positive breast cancer.

The results showed benefit to patients whose cancer had spread to their lymph nodes. In that group, the addition of pertuzumab resulted in a survival rate of 87.9% compared with 83.4% in the placebo group.

While the 4.5% improvement is modest, it translates to more diagnosed with early-stage breast cancer who are cured.

In a third study, adding tucatinib in metastatic HER2-positive breast cancer treatment improves survival rate.

A phase 2 trial showed the investigational tyrosine kinase inhibitor drug tucatinib improved survival in those with metastatic HER2-positive breast cancer.  The study, published simultaneously in The New England Journal of Medicine, compared tucatinib combined with the HER2 inhibitor drug trastuzumab and the chemotherapy drug capecitabine with  trastuzumab and capecitabine alone.

The study showed progression-free survival of 33.1% in the tucatinib combination group compared with 12.3% in the placebo combination group.

Overall survival at 2 years was 44.9% in the tucatinib combination group and 26.6% in the placebo combination group. Almost half of the study’s 612 patients had brain metastasis. The study showed 1-year progression-free survival of 24.9% in the tucatinib combination group compared with no patients with brain metastasis surviving in the placebo combination group.

Clinical trials are considered by breast cancer experts to be the gold standard for implementing new treatment options and medicines to ward off breast cancer and its recurrence.

During the 1980s, survival rates for breast cancer averaged 75%. Today, that survival rate is elevated to 90%, thanks to the many advances in treatment made through clinical trials.

Trial participants receive quality care designed for their type of cancer and are monitored carefully for any positive or negative changes regarding their health and cancer status.

The sites listed below have more information about current clinical trials.

NIH Clinical Research Trials and You (National Institutes of Health)
Learn About Clinical Trials (National Cancer Institute)
Search for Clinical Trials (National Cancer Institute)
ClinicalTrials.gov (National Institutes of Health)

Your Capital Women’s Care team is here for you should you have questions about your personal breast health plan, your recommended mammography screening schedule or discuss treatment options should you become diagnosed. Our knowledgeable, professional staff can guide you toward the best treatment possible for your individual diagnosis and address your concerns and questions to help you achieve and maintain optimal health and quality of life. 

Sources:

For more information about metastatic breast cancer:

Centers for Disease Control and Prevention (CDC) – call 1-800-CDC-INFO or go to their website: www.cdc.gov/cancer/gynecologic
National Cancer Institute (NCI) – call 800-4-CANCER or visit their website at www.cancer.gov

Additional Sources:

https://www.everydayhealth.com/hs/breast-cancer/metastatic-breast-cancer...
https://www.breastcancer.org/symptoms/types/molecular-subtypes
https://www.google.com/search?client=firefox-b-1-d&q=metastatic+breast+c...
https://www.cancer.org/content/dam/cancer-org/research/cancer-facts-and-...
https://mbcnbuzz.wordpress.com/2015/07/26/mbcn-responds-metastatic-recur...
http://mbcn.org/incidence-and-incidence-rates/
http://mbcn.org/standard-treatments-for-metastatic-breast-cancer/
https://www.nccn.org/patients/guidelines/content/PDF/stage_iv_breast-pat...
http://mbcn.org/october-13-national-metastatic-breast-cancer-awareness-day/
https://www.breastcancer.org/treatment
http://mbcn.org/most-common-statistics-cited-for-mbc/
https://www.ascopost.com/issues/november-15-2014/fast-facts-about-metast...
http://www.nsabp.org/About-NSABP/Blog/ArtMID/744/ArticleID/4/Clinical-Tr...
https://www.everydayhealth.com/breast-cancer/immunotherapy-may-help-some...
https://www.everydayhealth.com/breast-cancer/new-therapies-for-women-wit...
https://www.everydayhealth.com/breast-cancer/treatment/could-blood-bone-...
https://www.everydayhealth.com/breast-cancer/metastatic-breast-cancer-bl...

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