BY: MARIYA GUZOVA
The use of chemotherapy and radiation as a cancer treatment has had a cloud of controversy around it for a long time. The plethora of negative side effects, some of which you don’t recover from, has led to many people questioning the validity and effectiveness of the treatment. Although most doctors would consider it the most reliable form of cancer treatment, many cancer patients seek out alternative treatments, diets, and some have even called chemo a scam by pharmaceutical companies to keep people sick.
A lesser-known option for the treatment of cancer is High Intensity Focused Ultrasound (HIFU), which beams high frequency sound waves into cancer cells to heat them up and destroy them. The treatment isn’t very widespread and is used only on a handful of cancers, but when it is used, has very minimal side effects. Most patients only experience a minor soreness on the skin, but healthy tissue surrounding the tumour experiences no damage.
The reason this treatment can’t be used on many cancers is because the beam cannot pass through solid bone, and since the beam is precise and uses heat, it can only be used on small, targeted areas and not on more widespread tumours. Researchers at the University of Washington, however, are now developing a new way of using ultrasound waves as a cancer treatment that would allow them to liquefy large areas of cancerous tissue.
The technique, called histotripsy, vibrates to create bubbles in tumour tissue.
At high enough intensities, the bubbles collapse, and the shock waves from the collapse liquefy the tissue. This technique can liquefy whole tumours and be accelerated through the injection of micro-bubbles made of dissolved gases.
This treatment, also known as boiling histotripsy, is advantageous for a number of reasons. It can be achieved using the same technology used for HIFU, and also creates little to no damaging side effects. Another interesting benefit discovered by University of Washington researchers was that, once the tumour had been liquefied, the body would clear away the waste, but it left behind an extracellular matrix. That is the structure of cells that encased the tumour when it was there. This is a crucial element to regrow new, healthy tissue. Doctors have long sought a treatment that kept the structure intact, as it could be seeded with stem cells, which can use it to guide their growth.
“In some of our experiments, we discovered that some of the stromal tissue and vasculature was being left behind, or we had the idea about using this to decellularize tissues for tissue engineering and regenerative medicine,” researcher Yak-Nam Wang said. “In tissue engineering, one of the holy grails is to develop biomimetic structures so that you can replace tissues with native tissue.”
Clinical trials of histotripsy for patients with liver cancer are ongoing, and researchers are hoping to make this technique a reality for cancer treatment as well as regenerative medicine.