Revolutionary research has revealed an encouraging tactic to halt the return of cancer using a biodegradable gel.
The groundbreaking gel was created by scientists at the Dana-Farber Cancer Institute in Boston, MA. The gel was designed to deliver immunotherapy directly to the area from which a cancerous tumor has been removed surgically.
After testing the gel on mice during the surgical removal of breast cancer tumors, the researchers discovered that apart from assisting to prevent the recurrence of tumor at the primary site, it also eliminated secondary tumors in the lungs.
Senior study author Michael Goldberg, Ph.D. — of the Department of Cancer Immunology and Virology at the Dana-Farber Cancer Institute — and colleagues recently reported their results in the journal Science Translational Medicine.
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Surgical removal of the tumor is often the primary treatment for cancer that forms as solid tumors, such as breast cancer and lung cancer.
Goldberg explains, even when the tumor is removed, some cancer cells may still remain at the site, which can later form new tumors, or even spread to other areas of the body, a process known as metastasis.
“Indeed, while half of all cancer patients undergo surgery aiming to cure the disease, 40 percent of such patients experience a recurrence of the disease within 5 years,” Goldberg notes.
“Furthermore,” he adds, “it has been shown that the body’s natural process of healing the wound created by surgery can actually spur these residual cancer cells to metastasize to distant parts of the body and form new growths.”
Immunotherapy involves using drugs to stimulate the immune system and attack cancer cells. This can help to prevent cancer return and metastasis. However, immunotherapy treatment has some grim difficulties.
A main problem with immunotherapy is that it can attack healthy cells as well as cancerous ones, which can increase a patient’s vulnerability to other diseases.
“In this study, we sought to determine whether administering immune-stimulating drugs at the [right] place and the right time — at the site of tumor removal, before the surgical wound has been closed — could enhance the results of cancer immunotherapy.”
The track to ‘immunostimulation’
The researchers explain that after the removal of a cancerous tumor, the immune system uses most of its resources to heal the wound, rather than fighting any cancer cells that may have been left behind.
This can create an “immunosuppressive” microenvironment, in which cancer cells can bloom and spread, the scientists stated.
The scientists set out to transform this immunosuppressive microenvironment into one that is “immunostimulatory” — that is, one that can attack and destroy remaining cancer cells after surgery.
To achieve this deed, the researchers created a hydrogel laden with drugs that stimulate dendritic cells, which are immune cells that are involved in the initial immune response. They “present” any foreign invaders or diseased cells — such as cancer cells — to T cells, which carry out an attack.
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The gel contains a sugar naturally present in the human body, making it biodegradable. It is placed at the site from which a tumor has been surgically removed. The gel then gradually releases the drugs over a protracted period, which the researchers says increases its effectiveness.
The team tested the gel in mice that underwent the surgical removal of breast cancer tumors. The team made the decision to use the gel directly after tumor removal, rather than before.
“We reasoned,” Goldberg explains, “that it would be easier to eliminate a small number of residual cancer cells by creating an immunostimulatory environment than it would be to treat an intact primary tumor, which has many means of evading an immune system attack.”
Several months after surgery, the mice treated with the gel were much less likely to experience tumor regrowth, compared with rodents that received conventional immunotherapy delivery.
When the researchers injected breast cancer cells into the side opposite to where the original tumor was removed, the rodents treated with the gel showed no signs of tumor formation.
Also, the study discovered that the gel eliminated secondary tumors in the lungs of the mice — that is, it eliminated lung tumors formed from breast cancer cells that had spread from the primary site.
The researchers also replicated their findings in mice with primary lung cancer and a deadly form of skin cancer called melanoma.
Based on their results, Goldberg and colleagues believe that their gel-based immunotherapy could be an effective treatment strategy against a number of different cancers.