liquid-biopsy

Liquid Biopsy and its role in fighting cancer


Wrong diagnosis and wrong medications can lead to fatal results in person’s health. According to September 2014 bulletin of Sample Registration System (SRS), India has an infant mortality rate of 40 per 1,000 live births.Wrong drugs cause 50 deaths out of 1000 patients in India. Most of the times, a regular disease can exaggerate and become fatal because of the wrong diagnosis and medications. Same was the case with Mr. Deshpande (name changed) – which almost took a toll on his life.

When Mr. Deshpande, a 74 year old retired banker started suffering from abdominal pain, weakness, and fatigue, his wife was alarmed because he had always been very careful about his diet and exercise regime. Neither did he miss his regular check-ups. He wanted to lead his retirement exactly the way he had planned. However, all his plans were short lived because of his constant health issues after the retirement.

On the contrary, he also lost his weight drastically. When his wife took him to their GP, he referred them to an expert in the city where he was first diagnosed with adenocarcinoma of colon in November 2013.

After the diagnosis, the doctors suggested surgical resection which would be followed by chemotherapy. Doctors also advised a Positron Emission Tomography (PET) scan. This scanning is basically to check how the tissues and organs in the body are working. A year later,in November 2014, while testing, a mass measuring 2.1 x 1.7 cm was detected in the lung with speculated margins. The doctors assumed it as a metastasis from colon cancer and started with Capecitabine – a chemotherapeutic agent.

After the prescriptions, he was being continuously monitored with PET scans. However, despite of the chemotherapy which was ongoing since a year, the mass was continuously increasing in size.

Doctors were not sure if it was indeed a metastasis of colon cancer, or it was a result of tuberculosis or in a worse case, primary lung carcinoma?

After looking after a varied possibilities and options, he was referred for a liquid biopsy. However, Mr. Deshpande was reluctant because of general perception of the biopsies. He was only relieved when the doctors explained that the procedure is as easy as a simple blood test.

Liquid Biopsy showed mutation burden 4.4 % of total cell free DNA. It was an indication of active primary lung carcinoma. The Liquid Biopsy indicated therapeutic response to targeted anti EGFR therapies such as Afatinib, Gefitinib and Erlotinib.

Here, Gefitinib was prescribed to the patient. This drug is only effective in cancers with mutated and overactive EGFR. It started showing its results and the tumor began to shrink gradually. Repeat PET scan showed reduction in tumor size by 70%. That meant a great success of the accurate diagnosis and correct medications.

Liquid Biopsy after three weeks
Liquid Biopsy after three weeks

Five weeks later, detectable mutation burden in the cell free DNA obtained from plasma was negative. The mutation burden was reduced even more as compared to the previous analysis possibly due to Gefitinib therapy.

Mr. Deshpande is completely hale and hearty now. It’s interesting how one correct step towards the course of treatment can leave a huge impact on patient’s well-being.

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