Breast cancer facts in the Philippines

MANILA, Philippines — Breast cancer is currently the most common cancer among females in the Philippines¹ and worldwide². According to the CI5 database, breast cancer incidence and mortality have increased steadily in many Asian countries, most notably among Filipino women as we now have the highest incidence of breast cancer in Southeast Asia³. Breast cancer also comes in second to lung cancer in terms of mortality rate, making it a significant public health problem¹.

Based on foreign data, approximately 62% of women with breast cancer are diagnosed at an early stage when the cancer is still limited to the breast, for which the 5-year survival rate is 99%. Only 6% are diagnosed at stage 4, for which the 5-year survival rate significantly drops to 27%⁴. Locally, the 10-year survival rate among Filipino women with breast cancer is estimated to be only 57%, which is much lower compared to that in developed countries⁵. This lower survival rate is primarily due to a lack of awareness and low screening rates, resulting in a higher proportion of late-stage cases. Inadequate access and high cost of treatment also significantly contribute to the higher morbidity and mortality rates seen among Filipino breast cancer patients⁶.

Breast cancer is best treated using a multidisciplinary team (MDT) approach⁷. This means that doctors specializing in different areas of cancer diagnosis and treatment, along with other related healthcare professionals, work together to formulate a patient’s overall treatment plan that involves different treatment modalities. This treatment plan usually includes surgery, chemotherapy, radiotherapy, hormonal therapy, and targeted therapy depending on the patient’s stage, tumor characteristics, and other important factors that are considered on a case-by-case basis.

For early-stage breast cancer patients, the primary treatment consists of surgery to remove the tumor, followed by chemotherapy to eradicate any remaining microscopic cancer cells. Treatment given after surgery is called adjuvant therapy, and this aims to decrease the risk of the cancer from coming back.

For larger or rapidly growing tumors that have not yet spread outside of the breast and lymph nodes under the arm, systemic therapy using medications to destroy cancer cells is recommended prior to surgery, and this approach is called neoadjuvant therapy. This aims to shrink the tumor in order to make the surgery easier, and can also clear any microscopic distant disease that may not yet have been detected through routine diagnostic workup.

Adjuvant radiotherapy which involves the use of high-energy X-rays to target cancer cells is also added in certain cases, such as for large tumors, lymph node involvement, compromised surgical margins, and after breast conservation surgery⁸.

Certain special tests are done in order to further characterize tumors and identify additional treatment options. For patients whose tumors are positive for hormone receptors (i.e., estrogen and/or progesterone receptors), hormonal therapy is added as maintenance treatment after chemotherapy, most commonly in the form of tamoxifen and aromatase inhibitors. In HER2-positive cases, targeted therapy in the form of trastuzumab and pertuzumab is recommended to be added on top of chemotherapy⁸.

Breast cancer most commonly spreads to the bone, lungs, brain, and liver. For patients with stage 4 or metastatic disease, surgery is rarely done and systemic therapy becomes the primary mode of treatment. Chemotherapy can be given orally or intravenously, especially for patients with threatened organ function or rapid disease progression accompanied by severe symptoms. Otherwise, hormonal therapy is the preferred systemic treatment for hormone receptor-positive metastatic disease. Radiotherapy can also be done as a supportive treatment for certain sites of disease spread, such as painful bone metastases⁸.

In recent years, many novel systemic therapies that target critical signaling pathways involved in breast cancer development have emerged, and most of these are currently approved for advanced or metastatic breast cancer. Some locally available targeted therapies include CDK4/6 inhibitors which interfere with the cell cycle and are approved for women with ER-positive, HER2-negative advanced or metastatic breast cancer; and PARP inhibitors which prevent the repair of damaged DNA and are approved for patients with metastatic HER2-negative breast cancer and a BRCA1 or BRCA2 gene mutation after receiving prior chemotherapy.

Immunotherapy, which harnesses the body’s immune system to destroy cancer cells, is another novel treatment option that has emerged in this setting⁸. It is still unclear why not all cancer patients respond to certain specific treatments, but a lot of research is being done to develop better ways to predict which individuals are most likely to respond. More clinical trials are also being conducted to investigate how to better achieve sustained remissions and overcome treatment resistance.

Cancer treatment is individualized and does not follow a one-size-fits-all approach⁸. If you or someone you know has cancer, talk to a cancer specialist in order to come up with the most appropriate personalized treatment plan. It is important to discuss all your possible treatment options with your cancer care team in order to make the decision that is best for your situation.

Be informed, be aware, and remember that early detection and treatment are the best ways to overcome cancer.

For more information, you may visit The Philippine Society of Medical Oncology on their website and Facebook page.

Dr. Meredith Garcia-Trinidad is a cancer expert and patient advocate.

Pfizer Philippines joins the country in observing Breast Cancer Awareness Month in October.

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REFERENCES:

¹International Agency for Research on Cancer. World Health Organization. Globocan 2018 - Philippines. https://gco.iarc.fr/today/data/factsheets/populations/608-philippines-fact-sheets.pdf. Accessed on October 20, 2020.

²International Agency for Research on Cancer. World Health Organization. Globocan 2018 - World. https://gco.iarc.fr/today/data/factsheets/populations/900-world-fact-sheets.pdf. Accessed on October 20,2020.

³International Agency for Research on Cancer. World Health Organization. Cancer Incidence in Five Continents Time Trends. https://ci5.iarc.fr/CI5plus/Default.aspx  Accessed on October 20, 2020.

⁴Cancer.net Editorial Board. Breast Cancer Statistics. https://www.cancer.net/cancer-types/breast-cancer/statistics#:~:text=Sixty%2Dtwo%20percent%20(62%25),older%20than%2065%20(68%25). Accessed on October 20, 2020.

⁵Laudico, AV et al. 2010 Philippine Cancer Facts and Estimates. Philippine Cancer Society. Manila 2010. Page 20.

⁶Urrutia JD, Balmaceda CN, and Baccay E. Odds and Probabilities Estimation for the Survival of Breast Cancer

Patients with Cancer Stages 2 & 3. MATEC Web of Conferences 60. DOI: 10.1051/matecconf/20166003007. https://www.matec-conferences.org/articles/matecconf/pdf/2016/23/matecconf_iccbs2016_03007.pdf.  Accessed on October 21, 2020.

⁷Rajan, S et al. Multidisciplinary decisions in breast cancer:does the patient receive what the team has recommended? British Journal of Cancer. British Journal of Cancer (2013) 108, 2442–2447.

⁸NCCN Clinical Practice Guidelines in Oncology. Breast Cancer Version 6.2020 – September 8, 2020.