▶ Watch Video: Immunotherapy trial for rectal cancer offers hope for future

About a month before giving birth, Kelly Spill said she noticed something wasn’t right. When using the bathroom, she reported “seeing blood,” and the problem persisted for months after she gave birth. 

“I had a gut feeling that it was going to be cancer,” she told CBS News chief medical correspondent Dr. Jon LaPook. “I just knew.”

A colonoscopy later confirmed her suspicions, and a specialist told Spill that she had colorectal cancer, which most likely meant she would not be able to have another child due to the effects of chemotherapy, radiation and surgery. 

“Pretty much it would all be fried up down here,” Spill said. 

But a genetic mutation that only occurs in about 5% to 10% of people with her type of early stage cancer made her a match for an experimental trial at the Memorial Sloan Kettering Cancer Center. The immunotherapy is an antibody that allows the patient’s own immune cells to attack cancer cells.

“It sounded a lot better than chemo,” she said. “And I just thought, just, ‘What if that works?'”

Since undergoing the immunotherapy, Spill has fully recovered. She is now taking a trip around the country in an RV with her husband and son. 

“I’m slowly realizing what I went through, how hard it was and now it’s like the rainbow is here,” Spill said. 

And Spill isn’t alone in her recovery. 

In the trial, all 18 patients had complete resolution of their early rectal cancer, were cancer-free for up to two years and did not need to have standard treatments of radiation chemotherapy or surgery.

“We truly weren’t expecting this type of response where every single patient, the tumor’s gone and how quickly they responded,” Dr. Andrea Cercek, who led the trial treatment, told LaPook. 

After undergoing treatment in the groundbreaking trial, Imtiaz Hussain said he cried when the doctor called to tell him he no longer had cancer. 

“It’s just relief,” Hussain said. “You’re seeing the sun after like a year — it’s that kind of feeling.” 

Researchers agree the trial needs to now be replicated in a much bigger study, noting that the small trial focused only on patients with a rare genetic signature in their tumors and whose cancer had not spread beyond the colon.