Dr  Sanyo D'Souza

Due to rapid developments in molecular biology, cancer treatment has become far more advanced than conventional chemotherapy. Targeted therapy is a type of cancer treatment that is designed to attack cancer cells directly, where mutations responsible for their growth and survival are present. These drugs act on particular molecules in the body that cause tumour growth and then target them thereby stopping tumor growth, whereas chemotherapy acts in a non-specific manner.

Targeted therapies may be used at any stage of breast cancer treatment. These drugs may be given intravenous, subcutaneous (under the skin) or may be in tablet/capsule form.

Examples of such therapies include hormone, HER2, and CDK4/6 inhibitors. These act on accurate targets, and in general have less side effects than chemotherapy. Many a times, these therapies continue for long time (Eg. 5-10 years for hormonal tablets). The first targeted therapy to be used was Tamoxifen, decades ago which acts on hormone receptors.

Hormone therapies like Tamoxifen and Letrozole are used to prevent breast cancer recurrence in those, whose tumors have positivity for hormone receptors. In those with stage 4 disease, these drugs may keep the disease under control for more than three years when used in combination with other drugs like CDK4/6 inhibitors (Ribociclib, Abemaciclib).

Drugs targeting Her2 protein or gene include Trastuzumab, Pertuzumab and these have shown to reduce breast cancer recurrences by 30%. In those with stage 4 disease, these drugs may keep the disease under control for more than two years.

There are other drugs which target BRCA 1/2 genes (eg. olaparib) and may be used to prevent recurrence in some patients with early breast cancer and may be used in advanced disease.

The utilization of targeted therapy has enabled to increase the life span of those diagnosed with breast cancer, also maintaining the patient’s quality of life.

(Dr  Sanyo D'Souza is a Consultant, Medical Oncology, KMC Hospital, Mangalore)