Michael Strahan's teenage daughter has been diagnosed with brain cancer.

Isabella Strahan was told she has medulloblastoma, a common malignant tumor that arises in the part of the brain located by the base of the skull, in October and underwent emergency surgery later that month, just a day before she turned 19.

The college student insisted she is "feeling good" after a course of radiotherapy ahead of starting chemotherapy at Duke Children's Hospital + Health Center in Durham, North Carolina, next month.

She added on 'Good Morning America': "That's my next step. I'm ready for it to start and be one day closer to being over. .... I'm very excited for this whole process to wrap. But you just have to keep living every day, I think, through the whole thing."

Despite his daughter's diagnosis, Michael - who has Tanita, 32, and Michael Jr., 29, with first wife Wanda Hutchins, and Isabella and her twin Sophia with spouse Jean Muggli - still feels like the "luckiest man in the world" and is confident the teenager will "crush" the disease.

He told his 'GMA' co-anchor Robin Roberts: "I literally think that, in a lot of ways, I'm the luckiest man in the world, because I've got an amazing daughter.

"I know she's going through it, but I know that we're never given more than we can handle and that she is going to crush this."

Isabella began noticing symptoms when she began her studies at the University of Southern California in Los Angeles.

She said: "I didn't notice anything was off 'til probably like October 1.

"That's when I definitely noticed headaches, nausea, couldn't walk straight."

She initially dismissed her concerns but on 25 October, she woke up in the early hours of the morning "throwing up blood", prompting her family to urge her to seek immediate attention.

Michael said: "That was when we decided, 'You need to really go get a thorough checkup.' And thank goodness for the doctor. I feel like this doctor saved her life because she was thorough enough to say, 'Let's do the full checkup.' "

A full MRI discovered the 4cm fast-growing tumour and she had surgery on 27 October.

Isabella now plans to document her journey in a YouTube series to benefit Duke Children's Hospital and Health Center.

She said: "It's been like, two months of keeping it quiet, which is definitely difficult. I don't wanna hide it anymore 'cause it's hard to always keep in.

"I hope to just kind of be a voice, and be [someone] who maybe [those who] are going through chemotherapy or radiation can look at.

"Perspective is a big thing. I'm grateful. I am grateful just to walk or see friends or do something, 'cause when you can't do something, it really impacts you."