Two new experimental treatments have shown extraordinary success in helping cancer patients. Doctors are calling them "dream drugs" that are almost too good to be true.

Unlike traditional chemotherapy, which affects the entire body, the new immunotherapy drugs only tracks down cancerous cells. A toxin is then unleashed on the tumor without damaging the rest of the body.

The development is a breakthrough for patients since the effects of common cancer treatments can often feel just as damaging as the cancer itself.

One treatment, which targets breast cancer, is called ADC. Patients treated with the therapy, like 28-year-old Bridget Spencer, saw their risk of dying reduced up to 38 percent compared to people using conventional drugs.

"Every day I get up and go to work and dream about celebrating my 30th birthday, and one day living in a world that we're free of breast cancer," Spencer said.

The other landmark treatment, called Anti PD-1, targets kidney and lung cancers. Maureen O'Grady's Stage 4 lung cancer nearly disappeared with the treatment.

"It's extended my life, improved the quality of my life," O'Grady said.

Neither of the treatments are available to the public yet. But interested patients can talk to their oncologist about clinical trials.

Researchers and drugmakers have been trying to find ways to boost the immune system against cancer for decades, with little successes until now.