I have been hearing about immunotherapy to treat cancer for some time now but this breakthrough seems huge.

A 49 year old woman named Judy Perkins, for whom chemotherapy had failed, has been cured of advanced breast cancer that had already metastasized to other organs. She literally went from being told that she had only about three years to live to being cancer free.

It is the first time that a patient with late-stage breast cancer has been successfully treated by a form of immunotherapy that uses the patient’s own immune cells to find and destroy cancer cells that have formed in the body.

Judy Perkins, an engineer from Florida, was 49 when she was selected for the radical new therapy after several rounds of routine chemotherapy failed to stop a tumour in her right breast from growing and spreading to her liver and other areas. At the time, she was given three years to live.

Doctors who cared for the woman at the US National Cancer Institute in Maryland said Perkins’s response had been “remarkable”: the therapy wiped out cancer cells so effectively that she has now been free of the disease for two years.

“My condition deteriorated a lot towards the end, and I had a tumour pressing on a nerve, which meant I spent my time trying not to move at all to avoid pain shooting down my arm. I had given up fighting,” Perkins said. “After the treatment dissolved most of my tumours, I was able to go for a 40-mile hike.”

This reads like a shady spam email for essential (read: snake) oil therapies, but this is real science.

To perform this treatment, doctors use a person’s own immune system against their cancer. Cancer cells are analyzed and the patient’s own immune cells are basically reprogrammed to recognize the cancer cells as a threat. Then they are reintroduced into the body to fight the tumors wherever they are.

To create the treatment, doctors first cut small pieces of tissue from Perkins’s tumours and studied the DNA to find mutations specific to her cancer. They focused on mutations that disrupted four genes which produced an array of abnormal proteins in the tumours.

Next, the doctors extracted immune cells known as tumour infiltrating lymphocytes, or TILs, from the tumour biopsies. These are cells from the patient’s immune system that have invaded the tumour in a bid to kill it, but which failed in the task by being either too weak or too few in number.

After growing billions of these immune cells in the lab, the researchers screened them to find which ones would most effectively find and destroy the woman’s cancer cells by recognising their abnormal proteins.

The doctors treated Perkins by injecting 80 billion of the carefully-selected immune cells into her body. The therapy was given alongside pembrolizumab, a standard drug that can help the immune system to attack cancers. Tests after 42 weeks showed Perkins was completely cancer free. She has remained so ever since.

That is freaking amazing.

Think about it. Chemotherapy essentially works on the principle that cancer is more easily poisoned than healthy tissue. There’s obviously a great deal more complexity to it but it is basically a brute force approach. In cancer treatment the leap forward to immunotherapy is probably on par with the leap from muskets to Tomahawk missiles.

This is awesome news, because cancer sucks.