Isabella Strahan shares update after 3rd round of chemo for brain tumor

Isabella Strahan is celebrating milestones missed amid her ongoing treatment for a malignant brain tumor.

Strahan held a belated 19th birthday celebration for herself after she missed her actual birthday celebration in October while recovering from emergency brain surgery.

In a video shared Tuesday on her YouTube channel, the University of Southern California student baked birthday cupcakes alongside a friend, and then blew out candles on the cupcakes alongside her twin sister, Sophia Strahan.

"We're doing a little birthday celebration because I was not conscious for it," Isabella Strahan said in the video, as previous footage aired showing birthday balloons in her hospital room last October.

As the sisters celebrated again belatedly in May, their dad, "Good Morning America" co-anchor Michael Strahan, made a surprise appearance to join in wishing them a happy birthday.

Isabella Strahan was just one month into her freshman year at USC in Los Angeles last fall when she began experiencing headaches and nausea. After testing, doctors discovered she had developed a fast-growing 4-centimeter tumor, larger than a golf ball, in the back of her brain, which was diagnosed as medulloblastoma.

Medulloblastoma is a type of malignant tumor that accounts for about 20% of all childhood brain tumors, according to estimates published in the Journal of Clinical Neuroscience.

Since her diagnosis, which she revealed publicly in January, Isabella Strahan has undergone brain surgery as well as several rounds of radiation treatment.

She began chemotherapy in February and is expected to finish the treatment in early summer.

Isabella Strahan shared in a video posted on YouTube on May 21, that she had completed her third round of chemotherapy.

She was joined at Duke University Hospital, where she has been receiving treatments, by friends and family, including her dad and sister.

In another video, filmed once she returned home from the hospital, Isabella Strahan said she was feeling better and "not in much pain."

"Now I only have one round [of chemotherapy] to go, which is exciting," Isabella Strahan said, adding that she does have some fears about what her life will be like once she finishes her fourth and final round of chemotherapy.

I'm kind of scared, once I'm done, how I'm going to go back to normal life, because I feel like there's always going to be another treatment or something I have to do. But that's a later problem," she said. "Otherwise, I'm doing good."

Isabella Strahan announced in April that her doctors told her she would only have to do four rounds of chemotherapy, instead of the six rounds for which they had initially planned.

Now, with her rounds of chemotherapy reduced to four, Isabella Strahan said she will have more time off from treatments this summer before returning in the fall to her studies at USC.