What is Personalized Cancer Therapy? And How It’s Being Used Against Cancer

I think there are many contexts where the buzzwords “personalized cancer therapy” might be used. Sometimes it’s really just for the buzz, and there’s nothing interesting, but sometimes it’s way better than that.

Almost all cancer therapy is personalized. By that I mean that every single cancer patient will have a doctor to run tests and diagnose a very specific type of cancer (what organ or system is affected, what type of tumor, what grade, what stage, etc.) and then a prognostic will be made (for example, if the patient is already very old, diabetic and has a heart condition, a stage II breast cancer is going to be treated differently than when a young healthy patient with no other health conditions is diagnosed with stage II breast cancer). A good doctor will determine what is the proper treatment course for that specific patient with that specific kind of cancer. That’s already “personalized cancer therapy”. This has been done for decades.

Nowadays, new ways to personalize therapy are appearing. For example, targeted therapies are a kind of drugs that look for a specific “make up” that allows them to tell cancer cells apart from non-cancer cells. This is different from chemotherapy which is more broad (it targets fast replicating cells, which is not just cancer, but also cells from the GI track and hair, for example). When a patient has a specific type of cancer (let’s say breast cancer) the doctor might run additional tests to determine what sort of “make up” the tumor cells have (so what type of proteins are expressed on the surface of the cancer cells). Not everybody with breast cancer has the same proteins expressed on the surface of the cancer cells. So if we can determine what proteins are present, we can prescribe a specific targeted therapy that will attack those cancer cells and not any other cells. If you were to give the wrong targeted therapy to a specific patient, it wouldn’t do anything to their tumor, and the cancer would keep growing. So in this way, personalized therapy is becoming even more “personalized”. Not only is it specific to the type of cancer, it’s stage and grade, the health condition and age of the patient, it’s also becoming specific to the protein make up of the patient’s tumor. That’s great. This is becoming more and more common in the clinic.

Finally, the third way of using the buzzwords “personalized cancer therapy” is looking at “the future”. And that’s exciting, because there’s still a lot to do.

For example, still talking about breast cancer, there are about 100-200 different drugs on the market to treat breast cancer. If we have already decided that this specific patient was going to get drugs to reduce the size of the tumor, then surgery to remove what’s left of the tumor, then drugs again to get rid of the very last cancerous cells left, and that her cancer is HER-2 positive… well… that’s great, but there are still 10 different drugs on the market that the doctor could prescribe! Which one will they choose? Do they choose randomly?

The reality is that we don’t know which drug will work for this patient. Maybe only one out of the ten will work. Maybe a combination of three out of those 10 will work. Which three?!

That’s the puzzle that doctors still struggle with. They kinda pick “the drugs that usually work best, on average”. Or “the drug that has been on the market for the longest, because we’re used to that one and usually, it works ok”.

The dream would be to have a quick test that says “that’s it, that’s the drug !” or “that’s the drug combination” for this specific patient. Not just “we think that will work” and then it doesn’t. Just the right drug, 100% of the time. That would be great.

So that’s what researchers are working on.