Just last month, MesotheliomaHelp wrote about how the toxicity of cancer treatments, that kill many healthy cells, may open up new pathways for tumors allowing them to grow and spread. Now, another team of researchers support taking a less aggressive “kill all” approach to prevent the inevitable outcome of treatment resistance.
Researchers at Moffitt Cancer Center in Tampa, Florida, led by Robert Gatenby, M.D., study author and leader of the Cancer Biology & Evolution Program at Moffitt, want to attack cancer with adaptive therapy, which focuses on keeping resistant cells in check by maintaining an army of chemo-sensitive cells alive.
According to a Feb. 24 press release from the cancer center, bombarding cancer with the highest tolerated dose of chemotherapy, the typical approach, may effectively kill cancer cells in the short-term, but chemo-resistant cells escape the treatment and continue to grow and spread.
The old school approach to treatment, especially for mesothelioma, an incurable asbestos-caused cancer, is to take an aggressive approach in fighting the equally aggressive cancer. According to the researchers, however, by giving a lower dose of the chosen chemotherapy and keeping some chemo-sensitive cells intact, they can compete with the resistant cells and stop them from taking over.
“The goal is to enhance the value of therapy by using evolution in our favour rather than letting it beat us,” says Dr. Granby.
The approach, says Dr. Gatenby, adjusts treatment based on the size of the tumors and involves blasting the tumor with a high dose during its growth phase, then reducing the dosage as the tumor shrinks. Through this process, the patient maintains a higher quality of life with the lower toxicity levels, and the cancer is held at bay.
“Our goal is to keep playing this game with the tumour to keep it sensitive, and as long as we do that the patient is alive and fine,” says Granby in a Feb. 24 article in New Scientist. “Then they can have prolonged periods of time when they’re not getting any therapy at all.”
If the cancer recurs, another round of treatment again kills off the bulk of the cancer cells, but allows the patient to maintain a good quality of life. When tested on mice, this approach kept tumors small for much longer, “and after the initial 20 days only low doses were needed to prevent the tumours growing larger.” In addition, “therapy was stopped completely for 60 per cent of the animals, without the cancer progressing.”
The standard treatment protocol for mesothelioma patients is chemotherapy. However, the high doses often leave patients in fragile health from side effects including diarrhea, vomiting and anemia. Any treatment that improves quality of life and extends survival is a welcome approach.
Mesothelioma is responsible for the death of nearly 3,000 Americans each year.
The study can be found in the Feb. 24 issue of Science Translational Medicine.
- Cancer Center
- (Feb. 24 article in) New Scientist