Falling Through the Cracks: Combating Chemo-Resistant Cancer Cells
Since Nixon started the War on Cancer in the 1970s, the standard for cancer treatment has been chemotherapy, in which a cocktail of cytotoxic drugs are given at dosages the patient can tolerate without dying himself or herself. Unfortunately, some patients' cancers, especially those who have underwent years of chemotherapy treatments, eventually develop resistance to these drugs, forming "chemo-resistance" to render these drugs ineffective.
In order to prevent chemo-resistant cancer cells from wreaking havoc upon their hosts' bodies, researchers at the H. Lee Moffitt Cancer Center have developed a novel cancer treatment method termed "adaptive therapy." As opposed to chemotherapy's heavy drug dosage, Moffitt's adaptive therapy subjects cancer cells to short bursts of drug administration. Head developer of the treatment and leader of Moffitt's Cancer Biology & Evolution Program Dr. Robert Gatenby describes these short bursts as being more effective, as it serves to control a chemo-sensitive population of cells that prevents chemo-resistant cells from growing uncontrollably. Thus, researchers minimize the risk of growing exclusively chemo-resistant cells, whereas conventional chemotherapy's intense drugging kills off almost all chemo-sensitive cells to indirectly permit chemo-resistant cells to subsequently flourish.
In one study conducted by Gatenby's team, scientists administered varying doses of chemotherapy drug paclitaxel to mice with the common breast cancer. Mice were separated into three groups differing in treatment strategy: one receiving the conventional maximum dose (ST), one receiving the adaptive therapy dose in which paclitaxel is administered at a constant frequency but its dosage is decreased every time the cancer responded (AT-1), and one receiving the adaptive therapy dose in which paclitaxel is administered in identical doses but drug administration is skipped every time the cancer responds to a previous drugging (AT-2). Overall, researchers found the AT-1 treatment to be the most effective in both controlling and killing off the cancer cell population, mice in the group surviving substantially longer than their counterparts in the other groups.
Adaptive therapy, whilst not providing a cure for cancer, provides a practical solution to better combating the disease, as it relies purely on treatment strategies. It definitely represents a step in the right direction.
Click below to learn more about adaptive treatment and Gatenby's group's findings.