Breast cancer – from screening to treatment, health news and stories

Breast cancer is the most common cancer among women in Singapore, and the incidence of this disease has tripled in the last three decades. Between 2011 and 2015, a total of 9,634 women were diagnosed with breast cancer, which represents one in three cancers among women.¹.

Breast cancer subtypes

If a lumen is detected, a biopsy is performed to determine whether it is malignant (cancerous) or non-malignant. If it is malignant, it will be analyzed in more detail by tumor markers to determine the prognosis (risk of recurrence) and predictive (benefit of treatment) results.

Breast cancers can behave differently in different patients. This means that a patient's prognosis (chances of recovery and survival) and his treatment plan may be very different from those of others. Breast cancers are classified into three different subtypes depending on the state of estrogen receptors (ERs) and progesterone receptors (PRs) and HER2 receptors in the tumor. These include hormone-sensitive breast cancer, HER2-positive breast cancer and triple-negative breast cancer.

Knowing the characteristics of a tumor, such as its size, histological grade, and subtype, whether hormone receptor-positive or hormone-receptor-negative, could help predict whether the cancer will develop aggressively or less relapse and survival. For example, ER-positive tumors tend to grow less aggressively and may respond favorably to hormone therapies, while HER2-positive tumors tend to grow faster than other types of breast cancer and respond to HER2-targeting therapies such as breast cancer. trastuzumab.

Conventional management of breast cancer

Breast cancer treatment usually combines surgery, radiotherapy and chemotherapy. Depending on the size and position of the cancer, the surgery may involve removal of a part of the breast (lumpectomy) or entire breast (mastectomy). In patients with large tumors or lymph nodes under the armpit, and in those whose tumor is too large for lumpectomy, chemotherapy may be given first to reduce the tumor before undergoing surgery. To reduce the risk of cancer, radiation therapy, chemotherapy, hormone therapy and trastuzumab can be used to remove remnants of cancer cells, reducing the risk of cancer recurrence. Cytotoxic drugs used in chemotherapy are designed to kill cancer cells, but they could also destroy healthy cells and cause unwanted side effects.

One of the challenges of treating early-stage breast cancer is accurately predicting which patient may re-offend so that the treatment can be adapted accordingly. In addition to traditional methods of using patient and tumor characteristics, the study of gene expression patterns in the tumor can be a valuable tool in this regard. For example, the Oncotype DX 21-gene test recurrence score for invasive breast cancer has identified a group of women at very low risk of recurrence with hormone therapy alone. These women can be spared the side effects of chemotherapy and still have a good chance of recovery.

Revolutionary management of breast cancer

Traditionally, breast cancers have been characterized into biologically and clinically significant subgroups by histological grade and type. But now, it has been recognized that the heterogeneity of breast cancer can be supported by a myriad of mechanisms of genetic abnormalities.

Attention to genetic mutations and testing has been greatly enhanced in recent years, thanks to the "Angelina Jolie" effect. This is the phenomenon in which the famous Hollywood star discovered that she was carrying the mutation of the BReast CAncer 1 gene (BRCA1) and opted for a double preventive mastectomy in 2013. BRCA1 and BRCA2 were the first two major cancer susceptibility genes to be identified, in 1994 and 1995 respectively. A mutation in the BRCA1 or 2 gene results in a loss of ability of cells to repair damaged DNA, resulting in an accumulation of altered genetic material that may eventually lead to cell transformation into cancer. Therefore, a carrier of BRCA1 or 2 gene mutations has a much higher risk of developing breast and / or ovarian cancers. Interestingly, the same defect in DNA repair can also be exploited as a target for drug treatment. A new group of drugs known as PPAR inhibitors has been shown to be an effective treatment in breast and ovarian cancers with BRCA 1 or 2 mutations.

Evolutionary techniques of diagnosis and treatment

There are new developments in diagnostic and treatment strategies to effectively target these subgroups of breast cancer, including advanced genetic testing for cancer screening, hormone treatments, and HER2 targeting therapy. As a result, oncologists now have more treatment options, which they could incorporate into the most favorable treatment for the patient.

More than two thirds of invasive breast cancers are hormone sensitive and respond well to hormone therapy. Hormone therapy works primarily by decreasing the body's production of estrogen or by blocking or destroying the hormone receptors of cancer cells. They have been used successfully for:

• reduce the risk of cancer recurrence after surgery
• shrink a tumor before surgery to increase the likelihood that the cancer will be completely eliminated;
• reduce the risk of developing cancer in other breast tissues; and
• slow down or stop the growth of cancer cells that have spread to other parts of the body.

The development of CDK inhibitors 4/6, a targeted agent with the potential to inhibit the enzyme playing a key role in the proliferation of breast cancer cells, is another example of an evolution in the treatment of breast cancer. Thus, despite the exponential growth in the incidence of breast cancer, we can see the bright side: Breast cancer survival rates and the possibility of complete cure have improved considerably, thanks to early discoveries and cancer research over the last decade.