Though conventional cancer therapy aims to destroy cancer cells completely, it is better to use low doses of the chemotherapy drug and keep certain amount of cancer cells intact for better treatment, suggests a new study.
The study was done on mice with breast cancer, according to the report in Science Translational Medicine
, and is part of a growing movement in oncology to explore alternatives to high-dose chemo and its often toxic side effects.
‘Adaptive therapy with a high chemotherapy dose initially, followed by low doses keeps some drug-resistant cancer cells alive and thus controls cancer growth.’
"Our results suggest that this adaptive therapeutic strategy... can result in prolonged progression-free survival in breast cancer," said the study, authored by Pedro Enriquez-Navas and colleagues at the H. Lee Moffitt Cancer Center and Research Institute in Tampa, Florida.
Some researchers question the use of standard chemotherapy because it rarely wipes out cancer entirely, and leaves behind drug-resistant cells that can take over and lead to an explosion in tumor growth.
The new approach delivers continuous low-dose chemotherapy -- in this case paclitaxel -- that stabilizes the tumor by "maintaining a small population of drug-sensitive tumor cells to suppress the growth of resistant cells," said the study.
Standard doses of paclitaxel in mice shrunk breast tumors, but these tumors grew back once the treatment ended.
"Another treatment regimen that skips doses whenever the tumor shrunk also inevitably resulted in tumor progression," said the study.
"In contrast, adaptive therapy consisting of high initial drug doses followed by progressively lower doses as the tumor responded was more effective in controlling tumor growth than either standard therapy or dose skipping."
The study found that 60 to 80 percent of the mice treated by adaptive therapy could be "weaned off the drug completely without relapsing for an extended period of time."