Lelania Chapman hadn't left the house in three months, other than for her radiation treatments.

But when the single mother decided to take her nine-year-old son and three more neighbourhood kids for a hike at Cliff Falls in Maple Ridge, she ended up saving the lives of four boys who were trapped on the edge of a cliff.

"I still see their faces looking up at me," Chapman said.

She tried phoning for help, but couldn't get cell service in the forest.

"I wanted to go back to the truck to get a signal," said Chapman. "But one boy called for his mom. That's when I couldn't walk away."

She told the four kids with her to stay put, then began scaling down the first level of cliffs.

When she made it to the cliff's edge, she found a rope previous hikers had left behind.

She says she used it to tie herself to the biggest tree branch she could find, then threw the other end to the teenagers below.

'Pulling with everything in me'

As a group, they decided Chapman would hoist up the biggest boy first, so he could help her with the others.

"I was pulling with everything in me," she recalled.

Despite her body weakened by months of radiation treatments, she managed to drag the first child up the rock face to safety.

"When I pulled them up, their stomachs and chests were bleeding everywhere. I felt horrible."

From there, she hoisted the second boy and then the third to solid ground.

"The boys were so cold. Their lips were purple."

Feared rope would break

But the smallest boy refused to grab the rope, fearing it would break.

Chapman says she pulled her body across the ground to get as close to him as possible and asked for his name, which happened to be the same name as Chapman's oldest son. She says she knew she had to reach him.

Lelania Chapman was hiking when she heard kids screaming from cliff's edge 1:58

"He was so scared he wouldn't grab it."

Chapman believes he was suffering from hypothermia. At one point, the boy said he was just going to jump into the waterfall.

"I said, 'if you jump, I jump. And I don't want to go swimming right now.'"

It took 20 minutes, but Chapman says she eventually convinced the youngest boy to grab the rope, and was able to pull him to safety.

"None of us will ever forget it," Chapman said.

"I think if it was my sons calling for help, I would hope someone would jump down and comfort them. That's all I could think of."

Buoyed by new hope

Chapman was first diagnosed with stage three breast cancer in November. She finished a radiation treatment the day before the fateful hike, and now continues with radiation.

Also that same week, Chapman was told the cancer had spread. She has two malignant tumours, one in her thigh and another in her hip.

Chapman says she didn't want the boys she saved to know that she got badly hurt in the rescue. The ropes rubbed along her radiation scars and burned her. She got an infection and was bedridden for the next week in hospital.

Still, she says the event was a positive one for her and her life. "I was extremely depressed."

Some of the boys have since befriended Chapman on Facebook.

"I'm beyond thankful. They said 'thank you for saving us.' And I said 'I may have helped you out, but you guys saved me.'"