A medical first: Scientist treats her breast cancer herself using viruses

There are plenty of minor medical conditions that you can treat yourself—a cold, a wart, a temporary headache. But you wouldn't think of self-treatment for a more complex, chronic illness—or for cancer. That's what Beata Halassy (PhD), a virologist at the University of Zagreb in Croatia, has succeeded in doing. In 2020, the scientist discovered that she was suffering from a new recurrence of breast cancer, the second since the removal of her left breast.Instead of undergoing further chemotherapy, which she might not be able to withstand, the 50-year-old scientist chose to study the literature and informed her oncologists that she was going to test an unproven treatment on her own stage 3 cancer: intratumoral oncolytic virotherapy (OVT).OVT uses viruses to attack cancer cells and encourage the immune system to fight them. Most OVT clinical trials to date have focused on advanced metastatic cancer, but in recent years they have shifted to earlier-stage disease. In the U.S., a TTO (T-VEC) was approved in 2015 to treat metastatic melanoma, but no country has yet approved TTO agents to treat breast cancer at any stage.Two viruses injectedHalassy therefore chose to target her tumour with two different viruses consecutively: a strain of measles followed by a strain of vesicular stomatitis (VSV), both prepared in her own laboratory. For two months, a colleague injected the treatment directly into her tumour. Her oncologists agreed to monitor her during her self-treatment, so that she could switch to conventional chemotherapy if things went wrong.Both pathogens are known to infect the type of cell from which her tumour originated and have a good safety record, according to the case report, which was published in the journal Vaccines and reported on in Nature.“Edmonston-Zagreb measles is known to be safe in pediatric vaccines that have been used for more than 40 years,” and “OVT against measles has been clinically tested in patients with advanced stages of different types of breast cancer,” the Vaccines report stated.It also said, “VSV is an animal pathogen, but it is almost non-pathogenic for humans, causing flu-like symptoms in the worst case. It has been shown to confer protection against re-infection in a mouse model of breast cancer.”No recurrence for four yearsThe results were rapid. After just two months of treatment, “The tumour had considerably reduced in size and was not infiltrating either the underlying muscle or the skin above it, contrary to the initial value. As a result, it was successfully excised," observed Halassy and her co-authors. Analysis of the tumour after it had been removed showed that it was completely infiltrated by immune cells, lymphocytes, suggesting that the OVT had worked as intended and prompted the immune system to attack both the viruses and the tumour cells. As recommended, however, the scientist underwent one year's adjuvant treatment with trastuzumab because of the HER2 3+ phenotype of the excised tumour.Before this experimental treatment, the patient experienced two local recurrences of triple-negative breast cancer, at intervals of 22 and 21 months. However, after OVT, the patient has been in remission for 45 months or almost four years.The success of this self-treatment of locally recurrent breast cancer demonstrates that OVT can both shrink the tumour and induce anti-tumour immunity in patients with early stages of cancer, the report concluded. "As a result, better long-term disease control and prognosis may be achieved."While the authors say they encourage formal clinical trials evaluating OVT as a neoadjuvant treatment for early cancer, they say self-medication with oncolytic viruses should not be the first approach to treating diagnosed cancer.

A medical first: Scientist treats her breast cancer herself using viruses

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