Targeted therapy to treat cancer

October 25, 2006
By Syed Akbar
As October, the national breast cancer awareness month, draws to a close, oncologists and health experts suggest “targeted therapy” to treat the fast increasing menace. Of late, the incidence of breast cancer in India has been going up on par with developed countries mainly because of lifestyle changes including early menarche, lack of exercises and fatty diet.
Breast cancer has now become the commonest cancer in women in urban areas in India. It has emerged as the leading cause of death in women aged 35–55 years and the second leading cause of death in women of all ages. According to the International Agency for Research on Cancer, a World Health Organisation unit, about a lakh new breast cancer cases are reported every year in India.
Oncologists, doctors who deal with cancers, observe that breast cancer has certain patterns in its incidence. That it depends on the lifestyle of people. The incidence is higher in urban areas than in rural areas with National Capital Delhi leading the Indian chart. Delhi is followed by Mumbai, Chennai, Bangalore, Hyderabad and Kolkata.
An increasing number of cancer specialists are now prescribing targeted therapy or therapies to control breast cancer. Targeted therapy is nothing but a therapy with a specific molecular target. This method of treating cancer is efficient in more than one ways.
“In targeted therapy the biological processes that drive the cancer are understood and treatment is targeted at the biological process. In this process only cancer cells are targeted and the normal cells are spared,” says senior medical oncologist Dr SVSN Prasad. Targeted therapy is better than other traditional therapies. In chemotherapy or radiotherapy the normal tissue is also affected. Moreover, side-effects are minimal in the case of targeted therapy or therapies.
Targeted therapy is now increasingly being used for treatment of breast cancer, particularly in fighting HER2 or human epidermal growth factor receptor 2. HER2 is a gene that helps control how cells grow, divide and repair themselves. It directs the production of special proteins called HER2 receptors. Each healthy breast cell contains two copies of the HER2 gene, which helps normal cells grow. Sometimes a cell may have too many copies of the HER2 gene, which may lead to too much HER2 protein. This may play an important role in turning a normal cell into a cancer cell. The targeted therapy helps in prevention of recurrence and spread of the disease. Dr Prasad suggests that for more effective results targeted therapy can be combined with chemotherapy.
Dr Vijay Anand Reddy, radiation oncologist at Apollo Cancer Hospital, relates alarming increase in breast cancer to fast changing lifestyle of people, particularly in urban areas. Lifestyle changes like early menarche, lack of exercises and fatty diet are also the contributory factors.
“Today, breast cancer is the commonest cancer in women in urban population. India is fast catching up developed countries in terms of number breast cancer patients. Molecular therapies are referred as anti-bodies against HER2 antigens have really made a significant impact on the management of breast cancer patients,” he points out. One out of five women in advanced stage of breast cancer is HER2 positive.
Around nine per cent of women develop breast cancer during their lifetime, making it the second most common cancer in the world. In India, breast cancer accounts for 20 per cent of the total cancer-related diseases. According to WHO health statistics, breast cancer occurs at a younger age in India as compared to developed countries. HER2 type of breast cancer has greater risk of spread with faster growth of tumor. There are greater chances of the tumor coming back.
“Targeted therapies have emerged as the latest treatment option for people suffering from cancers. The therapy terminates the cancerous cells without affecting the quality of life of the patient. Indian oncologists prefer Herceptin, a unique biologic targeted therapy, for women with HER2-positive breast cancer,” says Dr Vijay Anand.
Since Herceptin targets mostly tumor cells that over-express the HER2 protein, it does not affect normal healthy cells. Patients on this therapy alone may be less likely to experience the side effects typical of other types of treatments, such as hair loss, fatigue, or a decline in certain blood counts.
Doctors observe that the best protection against cancer is awareness. Timely detection of cancer helps towards early treatment and prevents further progression of the disease.
The World Cancer Report states that action on smoking, diet and infections can prevent one third of cancers while another one third can be cured.
The World Health Organisation is of the view that cancer rates could further increase by 50 per cent to 15 million new cases in the next 14 years.
India has one of the high cancer mortality rates. There has been an increase in the incidence of breast cancer cases in Indian cities, points out Dr J Bandana, consultant gynaecologist.
“Lifestyle changes, smoking, usage of oral contraceptives, hormone replacement therapy, postponement of childbirth, obesity etc increase the risk of breast cancer,” she says. Dr Bandana suggests regular self breast examination for women and those over 40 should also undergo mammography once a year to nip breast cancer at an early stage.
Women with a history of first-degree relatives (mother, sister) suffering from breast cancer should be more cautious and regularly self examine their breasts, undergo mammography once a year, she observes.