Dr Aditi Thanky, Consultant Medical Oncologist and Haematologist at Sterling Hospital, Rajkot talks about breast cancer treatment and role of prognostic tests
According to a report published by WHO (World Health Organisation), in 2020, there were 2.3 million women diagnosed with breast cancer and 685 000 deaths globally. As of the end of 2020, there were 7.8 million women alive who were diagnosed with breast cancer in the past 5 years, making it the world’s most prevalent cancer. Breast cancer is the most diagnosed cancer among women worldwide, accounting for 1 in 4 cancer cases. It is the most frequent cancer amongst both sexes and is the leading cause of death from cancer in women. In India, one woman gets diagnosed with breast cancer every 4 minutes and one woman dies of breast cancer every 13 minutes, making it the most prevalent cancer among Indian women.
Survival rates for breast cancers are very high when the cancer is detected early and where treatment is available. Unfortunately, almost 50% of breast cancer cases are diagnosed at an advanced stage (Stage 3 and 4) in many low- and middle-income countries, such as India. Disease diagnosed in these stages is more difficult to treat and is usually incurable. The aggressiveness of breast cancer also depends on its type. TNBC (Triple Negative Breast Cancer) and HER2neu+ are more aggressive compared to ER+/HER2neu- breast cancer which is relatively less aggressive.
ER+/HER2neu- breast cancer patients, if diagnosed at an early stage have good prognosis leading to high survival rate. It has been observed and well documented in the literature that the majority of the early-stage HR+/HER2neu- breast cancer patients have no chemotherapy benefit. Not all the patients respond to the standard hormonal or chemotherapy similarly. Prognosis of each patient to the standard therapy is different. Typically, the clinicians gauge the prognosis of patients based on clinical factors such as tumour size, tumour grade, age of the patient, no. of positive nodes and Ki-67 status, ER, PR etc. Chemotherapy takes a toll on both physical and mental health of patients undergoing treatment. It is primarily designed to target the fast-growing cancer cells. However, it also destroys healthy cells in its course, causing further debilitating side effects in the patients.
Based on the above-mentioned risk factors, patients get prescribed with chemotherapy along with endocrine therapy. But these conventional clinical prognostic markers individually do not look at the disease holistically and thus lack insight on how each patient responds to the treatment more precisely.
What is a prognostic test?
A prognostic test predicts overall outcomes after standard treatment is given to treat breast cancer. They are different from diagnostic tests, which diagnose specific diseases and conditions. The difference between the two is that while a prognosis may be a guess as to the outcome of treatment or occurrence of a medical event, a diagnosis is actually identifying the problem and giving it a name. Prognostic tests predict a patient’s likelihood of developing a disease recurrence or experiencing a future medical event. Prognostic tests look for certain biomarkers within a patient’s body. Biomarkers are naturally occurring products in your body, such as antibodies, specific genes, patterns of gene expression or other biomarkers that can identify a particular disease or physiological process within an individual. Examples of biomarkers include everything from blood pressure and heart rate to basic metabolic studies and x-ray findings to complex histologic and genetic tests of blood and other tissues.
Early detection of breast cancer can save a patient from aggressive treatments such as chemotherapy, especially in ER+/HER2neu negative patients and can lead to a better “quality of life” for the patient.
Patients diagnosed at an early stage can take the help of prognostic tests to determine the clinical outcomes of the disease and the treatment. Prognostic tests assess the risk of recurrence of cancer for individual patients and enable the doctors to personalize treatment for each individual, resulting in improved quality of life and better clinical outcomes.
In certain cases, the patients may be identified as having lower chances of relapse of cancer based on clinical parameters or other prognostic markers like Ki67 as judged by the clinician, which might not be accurate on how cancer behaves in the future. The merit of the prognostic test is that it identifies the patient with higher chances of relapse based on cancer relevant features which helps in optimizing the treatment for each patient. This ensures that the patient is not under-treated and saves the patient from the risk of future recurrences of the cancer.
The importance of prognostic tests is evident by the fact that they are an essential part of breast cancer treatment as they are a part of major international cancer treatment guidelines such as NCCN (National Comprehensive Cancer Network).
There are many prognostics tests available but not all the tests have proven their clinical utility and usefulness on Indian patients. The only prognostic test that has been developed and validated on Indian patients is CanAssist Breast test.
Breast cancer takes a huge physical and emotional toll on the health of the patient. Taking the help of a prognostic test to determine the most suitable treatment option for a patient can bring us one step closer to ensuring an improved and happy life for the patient suffering from it.