Who knew that fat could actually play a role in fighting cancer? Well, it can — but we’re not talking about the kind of fat that you eat. We’re talking fat globules used to transport drugs straight to the offending tumor inside the body.
A research team, led by Dr. Mark Dewhirst, who is a radiation oncology professor and hyperthermia program director at Duke University Medical Center, has developed and tested a very effective way to slow down or stop cancerous tumor growth, which is also safer for a patient’s surrounding tissues.
This latest form of therapy is based on an existing concept — using “lysolipid-based temperature-sensitive liposomes” (LTSLs) in combination with heat to administer chemotherapy drugs to kill off tumors in a more efficient way. Basically, a liposome is a fat-based microscopic vehicle that is manufactured for transporting drugs to cells within the body. Heat is administered to the tumor through a tube — this process is called “hyperthermia.”
Liposomes are known to migrate toward high temperatures, so the extra heat around the tumor guides the LTSLs directly to the cancer-ridden area. It’s strange yet true! It’s already been tested as a way to treat cancer. However, the latest research has improved on it even more.
The recent study set out to determine whether or not timing of the hyperthermia portion of the treatment — before, during, or before and during infusion of LTSLs — could have an impact on a patient’s outcome. So, the researchers decided to test different scenarios on rats with 10 mm to 12 mm “fibrosarcomas” (a type of malignant tumor). All the rats were treated with a chemotherapy drug delivered via LSTLs; however, the hyperthermia was administered to the tumor site at different times in different groups.
One group received it before LSTL treatment, a second group received it during the treatment, and the third group received the hyperthermia before and during drug treatment. Remember that the hyperthermia helps the fat globules carrying the drugs target the cancer.
The researchers monitored the movement of the LSTLs in the rats’ bodies during treatment using magnetic resonance imaging (MRI), so they could make adjustments to the location of the heat source if the LSTLs seemed to be going astray. They also observed the growth rate of the tumor in each individual rodent after the treatment — until each reached five times’ the volume it was at on the day of treatment or for 60 days, whichever came first.
In all of the rats, the hyperthermia improved drug delivery. However, the rodents that were administered heat therapy at the same time that the LSTLs were released into their systems had the best results: more of the drug reached the tumor, plus it got there at a faster rate. In this same group, the drug also had a more potent anticancer punch — the average time for the tumors to reach five times’ their volume was 34 days. This is compared to the faster rates of 18.5 days and 22.5 days in the before and before/during hyperthermia treatment groups, respectively. So, hypothermia during LSTL infusion meant slower tumor growth and greater cancer-killing effects.
This study proves that the timing of heat delivery during the LSTL/drug treatment could make a huge difference in the treatment of a cancer patient, as could the use of the MRI to track the movement of the drug-laden fat globules. It means that less of a drug could be required to have a more potent tumor-killing effect. Moreover, this treatment is faster, more cost effective, and it’s less harmful for other tissues that might be affected by the drug that doesn’t make it to the tumor site.
Obviously, an untargeted blast of cell-killing drugs could have a negative impact on healthy cells. Now, we just need this treatment combination to be tested on humans.