Precision Oncology: Is Genomic Testing Worth It for You?

Precision oncology means treating the particular genetic faults in your cancer, not just the organ it started in. A lab studies your tumour’s DNA, finds the changes driving its growth, and your oncologist picks drugs aimed at those changes, where such drugs exist. That’s why two people with lung cancer can end up on very different treatments. Is the testing worth it? For some cancers, clearly yes. For others it adds very little. It comes down to the cancer, the stage and whether a matching drug is actually within reach.

Dr. Sandeep Nayak, who provides cancer treatment in Bangalore  , sees patients arrive with high hopes for this. “People hear ‘genomic testing’ and expect a magic drug. Sometimes that’s exactly what happens. More often the result helps us avoid a treatment that wouldn’t have worked, or tells us what to try next. I only ask for the test when the answer can change what we do.”

• It starts with a sample. That’s usually tumour tissue from a biopsy or an operation. Sometimes a blood sample is used instead, because tumours shed small traces of DNA into the blood.
• A lab reads many genes at once. This is called next-generation sequencing. It looks for changes that drive the cancer, and for markers such as how well the tumour might respond to immunotherapy.
• Your oncologist matches the findings to treatment. That could be a targeted drug, an immunotherapy, or a clinical trial. Sometimes nothing matches, and that’s a result too.
• Results aren’t instant. Expect a wait of a week or two, sometimes longer, depending on the test and the lab.

We explain our approach on the precision oncology page, and how treatment is tailored to the person on our personalised medicine page.

• Yes, in several advanced cancers. The European Society for Medical Oncology recommends routine tumour sequencing in advanced non-squamous lung, prostate, colorectal, ovarian and bile duct cancers, and has extended that to advanced breast cancer and some rare tumours. Our page on lung cancer treatment in Bangalore shows where targeted drugs come into the picture.
• Yes, when treatment has stopped working. A cancer that has changed or come back may now carry new genetic changes. We wrote about this in can prostate cancer change to resist treatment.
• Often, when the cancer is unusual. For rare tumours, or when doctors can’t tell where the cancer began, the genetic picture can point the way.
• Less so, when nothing will change. An early cancer cured by surgery usually doesn’t need it. And a lot of tests come back without a change that has a matching drug. If you’re weighing hormone-positive breast cancer, can targeted therapy replace chemo in ER+ breast cancer goes into it.

Cost matters too. These tests aren’t cheap, so it’s fair to ask your oncologist before you book: what would you do differently if the result comes back positive, and what if it doesn’t?

Whether genomic testing helps you is decided case by case, based on a few things.

• The type and stage of the cancer. Some cancers have well-known targets, others very few.
• Whether a matching drug exists. And whether you can realistically get it, in terms of availability and cost.
• Your tumour sample. There has to be enough good-quality tissue for the lab to read.
• What treatment you’ve already had. A cancer that has resisted earlier treatment may need a fresh look.
• Your general health. Some targeted and immune drugs suit certain people better than others.
• Clinical trials. Sometimes the best match is a trial rather than an approved drug.

The decision follows your reports, your scans and a frank talk with your oncologist.

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This content is published for educational and informational purposes only. It is not a substitute for medical advice, diagnosis or treatment. Please consult a qualified doctor about your own condition.