Treatment for cancer lies in our genes
NEW DELHI: It's a warning that should be heeded. Even as experts say
that the US will face a crisis in cancer care as an aging population
reaches its tumor-prone years, scientists have developed revolutionary
genomic therapies to tackle this looming crisis. So revolutionary, in
fact, that the treatment for cancer now lies in our genes itself.
Most cancers have variations which can be decoded by their DNA. Specific tests now zero in on these DNA, leading to targeted treatment. "Previously, cancers were treated with a crude approach using multiple chemotherapy drugs with many side-effects," says Dr S V S Deo, associate professor, department of surgical oncology, All India Institute of Medical Sciences, Delhi. "Targeted therapy is like a 'smart bomb' which specifically attacks cancer cells without harming normal tissues and has minimal side effects." It is being used successfully for breast, lung, gastrointestinal and blood cancer.
The success of these biological therapies depends on identifying the defect in a cancer cell, says Dr Radheshyam, consultant, medical oncologist, HCG Cancer Centre, Bangalore. "In some tumors, precision medicine is going to be a significant part of overall treatment. While there are hundreds of chemotherapy drugs, in advanced cancers, both chemo and targeted therapy are given."
These therapies are especially beneficial for hereditary cancer and selectively kill cancer cells by interacting with the receptors. "Some targeted therapies even have the advantage that they lead to minimal hair loss," says Dr Sunil Kumar Gupta, senior consultant, Rajiv Gandhi Cancer Institute and Research Centre, Delhi.
For these biological therapies, first tissue is taken from the tumour and a DNA test done. This will show up genetic abnormalities and mutations. Sometimes a drug that works on a mutated lung cancer cell can also work for some other cancer. So scientists have to find which treatment works for which mutation in which organ.
There are different DNA tests for different cancers depending on their mutations. For example, BRCA testing helps in identifying women at risk for developing breast cancer with a family history. "Gene profiling tests like Oncotype Dx and mamma print help in knowing the risk of cancer recurring and the treatment can be tailored to the patient's needs. They also provide information on the need for chemotherapy," says Deo. Oncotype Dx is, however, done by labs in the US.
Oncotype Dx, says Gupta, analyzes 21 genes in a tumor to determine whether the patient should be given only hormonal therapy (for low risk patients) or chemotherapy (high risk). For lung cancer, EGFR, AIK and Her-2 gene tests are done and for colorectal cancer, K-ras gene mutation analysis.
These revolutionary treatments are a mind-boggling field and expensive with the costs varying between Rs 3 lakh to Rs 10 lakh, says Deo. While some 25% of cancer patients at AIIMS receive some form of targeted therapy, at HCG hospital more than 100 patients have been treated with this procedure. And at Rajiv Gandhi Cancer Institute, plans are afoot to start a Hereditary Genetic Cancer Clinic.
Most cancers have variations which can be decoded by their DNA. Specific tests now zero in on these DNA, leading to targeted treatment. "Previously, cancers were treated with a crude approach using multiple chemotherapy drugs with many side-effects," says Dr S V S Deo, associate professor, department of surgical oncology, All India Institute of Medical Sciences, Delhi. "Targeted therapy is like a 'smart bomb' which specifically attacks cancer cells without harming normal tissues and has minimal side effects." It is being used successfully for breast, lung, gastrointestinal and blood cancer.
The success of these biological therapies depends on identifying the defect in a cancer cell, says Dr Radheshyam, consultant, medical oncologist, HCG Cancer Centre, Bangalore. "In some tumors, precision medicine is going to be a significant part of overall treatment. While there are hundreds of chemotherapy drugs, in advanced cancers, both chemo and targeted therapy are given."
These therapies are especially beneficial for hereditary cancer and selectively kill cancer cells by interacting with the receptors. "Some targeted therapies even have the advantage that they lead to minimal hair loss," says Dr Sunil Kumar Gupta, senior consultant, Rajiv Gandhi Cancer Institute and Research Centre, Delhi.
For these biological therapies, first tissue is taken from the tumour and a DNA test done. This will show up genetic abnormalities and mutations. Sometimes a drug that works on a mutated lung cancer cell can also work for some other cancer. So scientists have to find which treatment works for which mutation in which organ.
There are different DNA tests for different cancers depending on their mutations. For example, BRCA testing helps in identifying women at risk for developing breast cancer with a family history. "Gene profiling tests like Oncotype Dx and mamma print help in knowing the risk of cancer recurring and the treatment can be tailored to the patient's needs. They also provide information on the need for chemotherapy," says Deo. Oncotype Dx is, however, done by labs in the US.
Oncotype Dx, says Gupta, analyzes 21 genes in a tumor to determine whether the patient should be given only hormonal therapy (for low risk patients) or chemotherapy (high risk). For lung cancer, EGFR, AIK and Her-2 gene tests are done and for colorectal cancer, K-ras gene mutation analysis.
These revolutionary treatments are a mind-boggling field and expensive with the costs varying between Rs 3 lakh to Rs 10 lakh, says Deo. While some 25% of cancer patients at AIIMS receive some form of targeted therapy, at HCG hospital more than 100 patients have been treated with this procedure. And at Rajiv Gandhi Cancer Institute, plans are afoot to start a Hereditary Genetic Cancer Clinic.
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