Advances in cancer biology and immunotherapy and a better understanding of the various stages of how the disease develops have led to new drugs that limit side-effects even as they do not dilute the treatment.
The targeted therapies spare the body’s healthy tissue and focus on the gene that causes the cancer. These drugs use the body’s own resources to correct the molecular and genetic defects and mutations that cause cancerous cell growth. Many targeted therapies inhibit the growth factor receptor, specifically epidermal growth factor receptor [EGFR]. It is a protein on the surface of cells that is found in high levels in cancer cells. It binds with a specific growth factor on the external surface of a cell and triggers a signal for cell division. In cancerous cells, signalling is hyperactive, driving the uncontrolled proliferation of cells that ultimately leads to cancer. New drugs target the EGFR, interfering with cancer cell division by blocking the signals that direct the cancer cells to grow.
Some other drugs currently undergoing development are Antibody Directed Enzyme Pro-drug Therapy [ADEPT]. This targeted therapy carries an enzyme directly to cancer cells. A few hours after the antibody is injected, the pro-drug is administered. When this comes in contact with the enzyme, a reaction takes place, activating the anti-cancer drug and destroying the cancer cells, leaving the healthy cells intact.
Let us take a look at some cutting-edge technologies.
Cancer nanotechnology: Cancer nanotechnology is another emerging field of interdisciplinary research, cutting across the disciplines of biology, chemistry, engineering, and medicine. It is expected to lead to major advances in cancer detection, diagnosis, and treatment. Nanotechnology offers the opportunity to study and interact with normal and cancer cells in real time, at the molecular and cellular scales, and during the earliest stages of the cancer process.
Nanotechnology is being applied to cancer in two broad areas:
- Development of nanovectors, such as nanoparticles, which can be loaded with drugs or imaging agents and then targeted at tumours.
- High-throughput nanosensor devices for detecting cancer.
Chemo embolisation: The basic strategy behind this is to deprive the tumour of blood supply with the help of gelfoam [a medical device, intended for application to bleeding surfaces to stop bleeding] and also a chemo agent taking care of the cytotoxic [toxic to cells] aspect. The major tumour type on which this technology is being used is Hepato cellular carcinoma [cancer of the liver]. A technology called TACE [Trans Arterial Chemo Embolisation] is used where the blood supply to the tumour is cut using gelfoam. It is done by surgically inserting as well as supplying the tumour with a chemo agent administered intra arterially.
Chemo-embolisation enables doctors to deliver chemotherapy drugs via micro-catheters into select arteries that supply blood to the tumours. A high dose can be delivered directly to the tumour, while the remaining the organ is spared. Patients experience fewer side-effects than traditional chemotherapy since drugs bypass other organs.
Hyperthermia [also called thermal therapy or thermotherapy]: It is a type of cancer treatment in which body tissue is exposed to high temperatures [up to 45?C] which can damage and kill cancer cells, usually with minimal injury to normal tissues. It can also enhance the effects of certain anti-cancer drugs. Novel vehicles such as magnetic particles and glass beads to deliver treatment right to the cancer are being tested.
RFA [Radio Frequency Ablation]: It involves poking tumours with probes to sear the cancerous tissue away with intense heat. An electrical current runs through the probe and destroys the malignant cells within 15 – 45 minutes. This procedure is low-risk and heals faster compared to traditional surgery. This also finds a major role in the treatment of 80 per cent of hepatic tumours. It is performed by interventional radiologists guided by ultrasound, MRI or CT scan. This is offered to patients in selected oncology hospitals in Mumbai and Pune in Maharashtra.
Science is on the cusp of a cure for cancer that is very likely to come from such new therapies.
With inputs from Boman N Dhabhar, Head, BND Onco centre—centre for oncology treatment to cancer patients. He is also a medial consultant and haematologist with leading hospitals like Jaslok Hospital, Prince Aly Khan Hospital, Lok Hospital, Lilavati Hosp, Bhatia Hospital, and Jupiter Hospital.