(CNN) -- Kezia Fitzgerald and her 15-month-old daughter are both blondes with bright blue eyes. They both giggle easily and share a love of peaches.

The mom and daughter have more in common than Fitzgerald would like. Five months after Fitzgerald received a cancer diagnosis, so did her little girl, Saoirse.

Their cancers, albeit different types, had spread throughout their bodies.

"It's frustrating. It's unfair," said Fitzgerald, 28, who lives in Danvers, Massachusetts. "At the same time, there's nothing you can do to change it. The only thing you can do is heal and treat yourself."

This isn't the first time cancer has struck two members of a family at the same time. Fathers and sons have dealt with dual prostate cancer diagnoses, and mothers and daughters have fought breast cancer side-by-side.

But rarely do a young mom and her 1-year-old share the experience of losing their hair and getting chemotherapy together.

The difference is that Fitzgerald will remember everything, and her daughter will remember nothing at all.

A young mother learns of her cancer

During her pregnancy in 2010, Fitzgerald noticed swollen lymph nodes in her neck. She thought little of it, because she had experienced swelling before during allergy season. It didn't ache, she said. It just made her neck appear uneven.

In June that year, she and her husband, Mike, became first-time parents to healthy, 7-pound Saoirse.

But months after she gave birth, the swelling on the right side of Fitzgerald's neck persisted.

By January, her doctors determined the cause: stage three Hodgkin's lymphoma. Cancer is put into four stages that indicate the progressive spread of the tumor.

Hodgkin's lymphoma is the cancer of the lymph nodes, which are part of the immune system. It is considered one of the most curable cancers, and more than 90% of patients in early stages of Hodgkin's lymphoma survive at least 10 years.

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The tumor had spread to Fitzgerald's chest, neck and abdomen.

The stay-at-home mom was more concerned about Saoirse, then 6 months old.

The infant was crawling around the house, toting her stuffed purple gorilla, aptly named Grape Ape. She had learned to pet the family dog, Fallon. The active toddler was slurping broccoli and carrot puree and demanding her mama's attention.

How would she take care of her baby during cancer treatments? Fitzgerald wondered.

This also meant she could not breastfeed her daughter because of chemotherapy and PET scans, which use radiation.

Fitzgerald's parents pitched in to help with the baby and to shuttle her to various appointments.

Through her monthly chemotherapy, Fitzgerald dealt with nausea and fatigue. Her treatment was going well, and side effects were mild, so Fitzgerald thought the worst could be over.

Saoirse's cancer

One April morning, she and her husband noticed that Saoirse wasn't wandering around as she normally would. Even more startling, she had two black eyes.

"It looked like she had been in a fight at school," Fitzgerald said. "She had woken up, and her eyes were swollen. Her eyelids were black and blue and yellow, like she had been hit on both eyes."

Saoirse was also cranky and vomiting. She had swelling in both her ears and a bulge the size of an egg on her right temple.

"Her head looked like it was exploding," her father said.

Saoirse grimaced and touched her right ear, her eyes and the back of the head. She wrapped her hands around her stomach and whimpered in pain.

She was trying to tell them something.

They immediately rushed her to the emergency room. For three weeks, pediatricians and neurosurgeons focused on her head, taking CT scans to see whether she had bleeding there. The scans came out clean.

"It was crazy, because I'm going through treatment and dealing with my own low immune system, and she's not feeling well, so she wants to cling on me more," Fitzgerald said. "I had low energy, so that month was the hardest."

Finally, doctors found a tumor in Saoirse's abdomen. She was in stage four of a malignant cancer called neuroblastoma.

When her father heard the news, he went numb.

"I thought, 'My God, I'm at risk of losing both of my family members, the two most important people in my life,' " Mike Fitzgerald said.

Neuroblastoma is a malignant tumor that develops in infants and kids when their immature nerve cells turn into tumors instead of cells and fibers. The tumor usually begins in the adrenal glands, which sit on top of the kidneys and produce hormones.

It is one of the most common types of cancer for infants and children, behind leukemia and brain cancer.

Neuroblastoma can also form in the chest or next to the spinal cord and spread to the bones, bone marrow, liver, lymph nodes, skin and the space around the eyes.

The cancer's reach was extensive: It had spread to Saoirse's adrenal glands, bone marrow, ears and throughout her tiny body.

The doctors reassured Fitzgerald that she probably had not passed on the cancer during the pregnancy.

"Her mom's cancer is not known to be associated with neuroblastoma," said Dr. Esther Obeng, a clinical fellow in pediatric hematology and oncology at the Dana-Farber/Children's Hospital Cancer Center in Boston. But Obeng said she would recommend that they see a geneticist after treatment.

Saoirse needed chemotherapy right away. And Fitzgerald had to continue going to her treatment, too.

Cancer hasn't hindered Saoirse's development, her doctor said. Saoirse has high energy and met her milestones of walking and communicating on time.

Saoirse receives monthly chemotherapy that can last three or four days. The hardest part for Saoirse's parents is listening to her in distress.

When Saoirse has painful procedures, she begs her parents to intervene with mournful eyes.

"Mama!" she wails. "Dada!"

"I want to hold her and take the pain away and let her have some peace," her dad said. "As a parent, I just have to focus and know, no matter what she goes through, it's to help her get better."

He keeps it together in front of Saoirse.

"Every night when the baby goes to sleep, I step outside, and I cry," he said. "When you're alone, you let it all out. I feel a lot of stress and sadness and pain, because I want to help her."

The family with two cancers

Saoirse's parents juggle hospital appointments on their iPhones and living room calendar.

"They're a strong family," said Obeng, who is Saoirse's doctor. "That's a lot for people to go through."

Fitzgerald's husband, who works at a car dealership, has tried to work between his daughter's and wife's hospital schedules.

They retained health coverage through his employer and qualified for MassHealth, the public health insurance program in the state for low- or middle-income residents. It helps struggling families obtain health care to cover mounting copays.

Friends and family have chipped in through cancer fundraisers. And they've set up a blog discussing their struggles and triumphs with cancer.

On Monday, Saoirse went into the operating room clutching Grape Ape, her trusty stuffed animal.

Surgeons removed both of her adrenal glands because of damage from the cancer. Without these glands, she will have to take steroid hormone replacement for the rest of her life, Obeng said.

Saoirse will also undergo stem cell transplant using her own cells to rescue her bone marrow.

Saoirse's stem cells were collected from her blood after rounds of chemotherapy. These cells, which her doctor said are not affected by the neuroblastoma, will be treated and purified before being transplanted back into Saoirse's body. They are expected to help her grow healthy bone marrow.

She could be in the hospital for weeks. Still hooked to a catheter and other tubes, Saoirse hasn't been able to sit up yet. She stays in bed as her parent read books to her and watch "Curious George" with her. She started talking and even laughed with her daddy Friday.

Her doctors are happy with her progress, Saoirse's father said.

Her family received some good news over a week ago: Her mother's cancer is in remission.

They hope Saoirse will follow in her mom's footsteps soon.