October, worldwide, is designated as the Breast cancer awareness month. Pink ribbons. Pink colored tee-shirts. Pink banners. Going pink, wearing pink – the whole month is devoted to raising awareness about breast cancer in women. Healthcare institutions, pharmaceutical companies, and federations all over dedicatedly are doing their part towards a cancer-free world. Worldwide over 2 million women get diagnosed with Breast cancer. Out of all the diagnosed cases, Triple-negative breast cancer (TNBC) accounts for about 10-20% of the cases. Triple-Negative Breast Cancer is a form of Breast cancer that tests negative for estrogen receptors, progesterone receptors, and excess HER2 protein.
In layman’s language, normal breast cells have certain hormones and proteins for their proper development and function. Estrogen, a steroid hormone, in women, is a principal sex hormone and also helps in the development of breast, regulation of menstrual cycle, thickening of the inner lining of the uterus, and nourishing breasts for lactation. Progesterone helps in breast development for proper breastfeeding and lactation. In a similar line, HER2 is a growth-promoting protein. Thus, in the case of Breast cancer, Breast cells have higher levels of either of these hormones, which leads to surmounted cell division and proliferation. However, in the case of TNBC, the cancerous cells test negative for all of these three receptors.
What causes Triple-negative breast cancer?
So the question arises what might be causing this uncontrolled, unwanted cell division? Well, there can be several reasons except elevating hormonal levels, which are more or less similar to the reasons causing other forms of Breast cancer such as increase in age, family history, previous breast cancer diagnosis, reproductive history, radiation exposure, lifestyle habits such as alcohol consumption, cigarette smoking, obesity, or genetic aberrations (BRCA-1 and BRCA-2 mutations). Several studies point to unrelenting stress that is also associated with an increased risk of TNBC.
Who gets affected by TNBC?
Triple-negative breast cancers have an early onset. Most people who are diagnosed with TNBC are younger than 50. Studies have shown that people who have a family history of breast or ovarian cancer are more likely to get diagnosed with TNBC. However, certain people, it seems, are more susceptible to developing TNBC. Epidemiology studies show that African-American or Hispanic populations are more likely to get TNBC as compared to other ethnicities. Furthermore, clinical outcomes of TNBC are comparatively worse in African American women as compared to European American women (Bauer KR et al.). The fact is backed by several pieces of research, one being led by Bowen and colleagues that interrogated a UK based breast cancer cohort. The findings revealed 22% of the total cases under review to be black women with TNBC in comparison to 15% of white women.
Then, there is also a correlation between breastfeeding and TNBC. Studies revealed that women during breastfeeding shed the fat in their breasts, decrease the levels of hormones, namely estrogen and progesterone. And it also lowers down the risk of ovarian cancer by preventing ovulation, thus reducing the risks of TNBC or breast cancer overall. Additionally, most of the TNBC patients who have a family history of cancer inherit the mutations in the BRCA1 and BRCA2 genes.
What are the similarities?
The symptoms of TNBC mimic the symptoms of other Breast cancers including, lumps in the breast, pain or redness in that area, nipple discharge, skin discoloration, and others. However, what differs is the treatment approaches used to combat TNBC. Triple-negative breast cancers fall into the category of hard-to-treat cancers. Since there is no relation between receptors/ hormones and TNBC, hormone therapy here is rendered pretty much futile. They, however, can be treated with surgery, radiation therapy, and chemotherapy, or a combination of these. Chemotherapies are the standard of care for Triple-negative breast cancer. These are given as neoadjuvant or adjuvant as both first as well as the second-line of treatment.
What are the recurrence rates?
Although the response to chemos is appreciable, the chances of relapse of cancer in TNBC are disturbingly high. After initial treatment, some of the rogue cancerous cells escape the wrath of medications or therapies, travel down through the lymphatic system, and then there are chances of recurrence. There exist shreds of evidence that TNBC has a worse clinical outcome and a unique pattern of recurrence than other forms of breast cancers. After diagnosis, TNBC patients experience the highest chance of relapse of cancer within the first five years; however, if the patient is cancer-free for that duration, the chances of cancer relapse lower down significantly.
What lies ahead?
Triple-negative breast cancer is comparatively aggressive and difficult to treat. It has a poor prognosis, and only a handful of the targeted therapies are available that can tackle TNBC. The rate of its metastasis further adds to the aches and pains associated with TNBC. Several studies have demonstrated that TNBC has higher chances to metastasize to other parts of the body, especially to the brain and lungs, thus recur after the treatment. But, there has been a lot of activity going on in the TNBC domain. With the burden, Triple-negative breast cancer has poised in front of the world; no wonder the goal of effectively target it has taken the front burner. Past decades witnessed several therapies setting up their foot in the sector. The scientist community is vigorously testing PARP-inhibitors, immunotherapies, and a combination of novel and preexisting therapies to treat TNBC. Pharmaceutical and Biotech companies in the TNBC market are proactively working towards developing and manufacturing therapies for TNBC. Several regional, national, and international institutions are working shoulder to shoulder to bring tumult of joys in the form of an efficient, effective, and safe therapeutic advantage to the patients.