There’s a revolution occurring in cancer treatment, and it could mean the end of chemotherapy.
When it comes to taming tumors, the strategy has always been fairly straightforward. Remove the offending and abnormal growth by any means, in the most effective way possible. And the standard treatments used today reflect this single-minded approach — surgery physically cuts out malignant lesions; chemotherapy agents dissolve them from within; and radiation seeks and destroys abnormally dividing cells.
There is no denying that such methods work; deaths from cancer have dropped by around 20% in the U.S. over the past two decades. But as effective as they are, these interventions can be just as brutal on the patient as they are on a tumor. So researchers were especially excited by a pair of studies published in the New England Journal of Medicine last week that showed a new type of anti-cancer drug, which works in an entirely different way from chemotherapy, helped leukemia patients tally up to an 83% survival rate after being treated for two years.
The report was only the latest to emerge since 2001, when imatinib, or Gleevec, the first drug to veer away from the take-all-comers approach on which cancer therapies have been built, accomplished similar improvements in survival for patients with chronic myeloid leukemia (CML) and gastrointestinal stromal tumor (GIST).
Could the end of chemotherapy be near?
“It’s a question we are all asking,” says Dr. Martin Tallman, chief of the leukemia service at Memorial Sloan Kettering Cancer Center. “I think we are definitely moving farther and farther away from chemotherapy, and more toward molecularly targeted therapy.”
It’s the difference between carpet bombing and “smart bomb” strategies for leveling an enemy – in this case a fast-growing mass of cells that can strangle and starve surrounding normal tissues. Targeted therapies, as they are called, are aimed at specific pathways that tumor cells use to thrive, blocking them in the same way that monkeying with a car’s ignition, or it’s fuel intake, can keep it from running properly. The advantage of such precise strategies is that they leave healthy cells alone, which for patients means fewer side effects and complications.
Already, patients diagnosed with GIST can avoid chemotherapy altogether, thanks to Gleevec. “No patient diagnosed with GIST should be getting chemotherapy today,” says Demetri. Patients who develop certain types of lung cancer or melanoma caused by a cancer-promoting mutation known as BRAF are also starting to replace toxic chemotherapy agents with new, more precise medications designed to thwart the BRAF pathway.