Preventing Cancer Recurrence with IMMUNOTHERAPY GEL Used During Surgery

A biodegradable gel with immunotherapy properties has been shown to be a potentially effective strategy for preventing cancer recurrence or metastasis.

Developed by Dana-Farber Cancer Institute scientists, the gel is designed to be applied where a cancerous tumor has been surgically removed and activate immunity against cancer cells. It is therefore a locally administered immunotherapy drug.

In mice with breast cancer models, this immune-stimulating gel, applied to the surgical wound after tumor removal, reduced recurrence at the tumor site and also shrank tumors elsewhere. Thus, locally delivered immunotherapy produced a systemic immune response.

Reducing Recurrence Risk After Cancer Surgery

For patients with solid cancers such as breast and lung cancer, surgical tumor removal is usually the preferred treatment. Subsequent preventive measures to stop recurrence are called adjuvant therapy . Currently accepted forms are chemotherapy and radiotherapy given to kill cancer cells directly. A locally administered immunotherapy drug has not previously been approved as preventive treatment after cancer surgery.

Even after complete surgical removal, some cancer cells may remain locally (residual cancer cells). They can form new tumors and spread elsewhere in the body. This process is called metastasis . Patients treated only with surgical removal therefore experience more recurrences and often need adjuvant treatments.

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There is also evidence that the surgical wound's natural healing processmay help residual cancer cells metastasize to distant sites and form tumors.

Immunotherapies

Immunotherapyincludes various drugs and practices designed to stimulate immunity to attack cancer cells. The most commonly used drugs today are anti-PD-1, anti-PD-L1 and anti-CTLA4 monoclonal antibodies, classified as "immune checkpoint modulators," and most are given by intravenous infusion.

Immunotherapy is not free of side effects: activated immune cells may attack healthy cells as well as cancer, potentially increasing susceptibility to other diseases.

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This study therefore investigated delivering immune-stimulating drugs to the tumor removal site before wound closure — at the right place and time — giving rise to the concept of perioperative (during surgery) immunotherapy .

Researchers emphasize that after tumor removal, the immune system devotes most resources to wound healing rather than fighting cancer cells. This environment may create an immunosuppressive tumor microenvironment that benefits cancer cells. They designed the biodegradable gel to transform it into an immunostimulatory environment capable of attacking and destroying residual cancer cells after surgery.

For this, they created a hydrogel loaded with drugs stimulating the immune system's dendritic cells . These cells process foreign substances or diseased cells (such as cancer cells) and present them to the main immune fighting cells, T lymphocytes.

The dendritic-cell-stimulating gel placed at the removal site contains a naturally occurring, biodegradable sugar found in the human body. It slowly releases the drugs over a prolonged period, maintaining effectiveness.

Several months after surgery, gel-treated mice had fewer tumor recurrences than those receiving conventional immunotherapy. Secondary tumors in the other breast and lungs, where cancer cells had been implanted, also shrank or disappeared.

Conclusion

Treatments stimulating immunity against cancer, called immunotherapies, are increasingly important in oncology. Cancer-specific immune activation nevertheless appears possible only through advanced biotechnology. This was also a mouse tumor model, and mouse tumor microenvironments are much less complex than humans’. In the future, local immunotherapy following cancer surgery or treatments locally destroying the tumor, nonsurgical cancer treatments may become part of preventive approaches. This study is notable for demonstrating that possibility.

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