Precision Oncology

Cancer occurs due to uncontrolled growth of abnormal cells in our body and can affect any organ. The concept of precision oncology is based on the fact that this growth results from development of mutations in genes involved in growth regulation and/or DNA repair of the cells. Mutations largely acquired during one’s lifetime called sporadic mutations are present only in the tumour cells. Sometimes mutations are inherited from parents leading to increased susceptibility to a particular cancer. These are present in parental germ line cells and such cancers are called hereditary cancers. Identifying these mutations has been the key step towards development of precision oncology.

By identifying these mutations, drugs can be developed to attack these anomalies and thus kill the cancer cells. Treatment that is based on targeting these mutations has been shown to improve responses and thereby outcomes in cancers that are driven by them and forms the basis of precision oncology.

The mutations are identified by doing special tests after isolating the DNA and RNA of the tumor tissue. Doing these tests requires special technology and expertise and is done in laboratories which have adequate infra structure for the same. Due to the complex nature of the tests, the results may take 2 to 3 weeks or more. Depending on the results, it is determined if the patient is a suitable candidate for any targeted therapy. Sometimes no mutation may be identified and it becomes difficult to prescribe precise targeted therapy.

The benefit of precision oncology is personalized treatment based on the cancer type. The goal is “to treat the right patient with the right treatment at the right time”. Currently it is mainly used for patients with advanced malignancy and those limited options of treatment like certain rare cancers.

While biopsy tissue is necessary for detecting many of these mutations, newer advances allow for detecting the same anomalies in the blood so that biopsy can be avoided. However, this is currently limited to a few cancers like lung and breast.

Increasing research continues in the field of precision oncology not only to identify newer mutations, but also to develop drugs which can target them and result in control of cancer growth. However, treatment with targeted drugs can result in tumor acquiring newer mutations leading to drug resistance. And repeated biopsies and testing as disease advances may be necessary.