Dr Devi Nair, Health Economist, Goa Institute of Management and Dr Krishnanuni Raveendran, Resident, Sichuan University, China explains about precision medicine and highlights that it is a better option in resource limited situations of Indian health system and it will reduce cost of cancer care and improve outcomes
Cancer is the second largest cause of mortality and morbidity in India, about 2.5 million people living with cancers: and over 11,57,294 lakh new cases registered every year1. International Agency for Cancer Research (IARC) says that breast cancer, oral cancer and cervical cancer are the most common cancers in India and in 2018, about 3.75 lakhs people were diagnosed with 2.2 lakhs died from one of these cancers. India figures at the top of the list of high mortality among cancer patients in Asian countries and the disease starts younger ages- one decade early than western countries. But with limited cancer care centres and oncologists, the domestic situation of India is much worse in comparison to global scenario2.
Currently, cancer patients, receive a combination of treatments, including surgery, chemotherapy, radiation therapy, and immunotherapy. Usually patients receive the same type of treatment depend on the type of cancer, location, its size, and has metastasis. Evidence show that, these standard therapies are effective for about 50 per cent patients only. Even so, patients may respond differently to standard therapies, until recently, doctors didn’t know why this happens. Now scientists understand that patients’ tumours have genetic changes-DNA mutation, that cause cancer to grow and spread and the changes that occur in one person’s cancer may not occur in others who have the same type of cancer. People with same forms of cancers needs different type of therapies based on their DNA mutation. Hence there is a need for targeted therapeutic approach in cancer patients and personalised cancer care for better outcomes3.
Precision medicine is an approach to patient care that allows doctors to select treatments that are most likely to help patients based on a genetic understanding of their disease. This may also be called personalised medicine. According to the Precision Medicine Initiative, precision medicine is “a new and emerging approach for treatment and prevention that takes into account of individual variability in genes, environment, and lifestyle for each person”. 4
This approach will support physicians to decide which treatment and prevention strategies fit for a particular disease will work in which groups of people. It is in contrast to the traditional one-size-fits-all approach, in which treatment and prevention strategies are developed for all have the same types of symptoms or disease. As per the National cancer institute, “using genetic changes in a patient’s tumour to determine their treatment is known as precision medicine”.
To figure out the changes in cancer cases, patients needs to go for a biopsy, then the sample will send for checking genetic changes in that particular case and is called DNA sequencing or molecular profiling. Once cancer causing genetic changes are identified in a cancer patient they can move for targeted therapies. Targeted therapy is the foundation of precision medicine. It is a type of cancer treatment that targets the changes in cancer cells that help them to grow and spread. Most types of the targeted therapies help to treat cancer by interfering with specific proteins which helps tumours grow and spread throughout the body. Targeted therapies can also help to boost your immune system to work against cancer. Some therapies will prevent blood supply to the tumours and help tumour to shrink.
With precision medicine, physicians can select appropriate therapy or treatment protocol. This avoid unwanted interventions, will minimise harmful side effects and ensure more successful outcome in a cost-effective way. For example: About 30 per cent of patients with breast cancer have a particular form of over expressed protein called HER2, which is non-responsive to standard therapy and recurrence of tumours are common. Statistics says that only 50 per cent of breast cancer patients successfully fighting against the disease. Trastuzumab is the approved medicine for patients with HER2 positive tumours that reduced recurrence by 52% in combination with chemotherapy.5
Another example, a patient with lung cancer having Epidermal Growth Factor Receptor (EGFR) gene can be treated successfully with EGFR inhibitor drugs.
Thus, understanding each patient’s “cancer” is unique, and by making accurate diagnosis, and doctors have always tried to tailor better treatment that can be achieved upon matching each cancer patient with the best of targeted personalized treatment options. Precision medicine is a multi-faceted approach to patient care. It not only helps to diagnose and treat disease, also helps in risk assessment, prevention through life style or behaviour modification in risk groups, early detection of molecular changes, accurate diagnosis and adoption of individual treatment strategies and better treatment outcomes6. Even though many researches are making progress in the area of cancer care, the precision medicine approach is not yet approved as a routine for cancer care in India. There is ample evidence that, many cancer cases can be curable at early stage through screening and early detection. Especially breast cancer in young adults. The situation is worsened when people with a genetic predisposition to cancer, for example, incidence of breast cancer in close relatives, also feel no necessity to get screened. Currently doctors are using precision medicine to treat certain types of cancers only- e.g. breast cancer, lung cancer, skin cancer, colon cancer, and pancreatic cancer.
Is it a need for Indian health system?
Precision medicine is an emerging approach especially in developing countries. In India the scope and potential for adoption of precision medicine is high. There are few reasons behind this statement. The first reason is, dramatic increase in number of cancer cases with in one decade and the risk factors for cancer is also very high in the country. Second, treatment of cancer causes substantial financial shocks and pushing many families towards financial catastrophe and poverty. A large number of households in India incur financial debts and sell assets in order to finance their health care payments for cancer care7.
The main reason behind the impoverishment is cost of cancer medicines. Moreover, Insurance coverage is relatively low and most of the medical expenses are covered through out-of-pocket expenses and will leads to financial impoverishment.
Third, it is estimated that only around 40 per cent of the cancer medicines in current use are seems to be effective and appropriate for the patients. When we are treating cancer patients’ various factors such as age, gender, genetics factors, stage of the disease, metastasis, comorbidity and usage of other drugs all these things should take in to account. India has a heavy burden of inherited diseases driven by the unique genetic characteristics in the population that require attention for early diagnosis, right treatment, and management. That is the promise of precision medicine in India. Health system in India is fast in adopting new technologies. Even though limited access to screening programs, delay in diagnosis, time consuming investigations, financial problems related to long term care etc are the challenges of cancer care in India. Many cases were diagnosed in the late stages and will increase the mortality of cancer cases. Primary prevention, early detection and appropriate interventions hold the key to success in cancer care. So precision medicine is a better option in resource limited situations of Indian health system and it will reduce cost of cancer care and improve outcomes.
References
- Global Burden of Disease Study, Lancet,2017
- Indian Council of Medical Research (ICMR) Department of Health Research – Ministry of Health & Family Welfare Government of India, Feb.2019
- National cancer Institute report, NIH,2018
- Precision medicine initiative, NIH,2018
- Piccart-Gebhart MJ, Procter M, Leyland-Jones B, et al. Trastuzumab after adjuvant chemotherapy in her2-positive breast cancer. N Eng J Med 2005; 353:1659-72; Romond EH, Perez EA, Bryant J, et al. Trastuzumab plus adjuvant chemotherapy for operable HER2-positive breast cancer. N Eng J Med 2005; 353:1673-84.
- Sen M (2016) Personalized Medicine is the Key to Effective Cancer Treatment. J Cancer Diagn 1: e101. Doi: 10.4172/2476-2253.1000e101
- Rajpal S, Kumar A, Joe W (2018) Economic burden of cancer in India: Evidence from cross-sectional nationally representative household survey, 2014. PLoS ONE 13(2): e0193320. https://doi.org/10.1371/journal.pone.0193320