Portland, Oregon (CNN) All Erika Zak wants to do is play with her daughter on the playground. Take her to the zoo. Walk her to school.

She's never been able to be the mother she longs to be.

At 38, Erika is dying.

Her battle to live began almost as soon as her daughter, Loïe, was born four years ago, when Erika was diagnosed with stage 4 metastatic colon cancer that had spread to her liver.

The cancer was removed from her colon and, her doctors say, she responded well to treatment. But a microwave ablation surgery last year to remove two tumors from her liver went terribly wrong, leaving a fist-sized hole in her liver and destroying her bile ducts.

Every day since has been a fight to survive. She's been hospitalized 19 times in Oregon over the last 12 months for infections, bleeding and an array of other health issues.

She has high blood pressure in her liver, which backs up the veins in her esophagus and can be catastrophic. Her surgical oncologist constantly worries she will fall ill with a bad infection and die.

Without a liver transplant, her doctors say Erika will likely die before the end of the year.

"Every time she calls me and has a fever and some bleeding, we all hold our breath, worried: Will this be the time Erika bleeds to death?" says Dr. Skye Mayo, her surgical oncologist at Oregon Health & Science University.

"This is kind of the end game of what liver failure looks like."

More than 100 doctors at three of the nation's top medical centers have weighed in on her case, which is complex and exceedingly rare. Their conclusion: The only way to save Erika's life is to give her a new liver.

After weeks of evaluation at the Cleveland Clinic in December and January, Erika finally got her big break.

On February 2, doctors there approved putting her on the wait list for a liver transplant.

The news changed everything. Erika finally had hope. Around the house, 4-year-old Loïe would say, "Mommy, when you get a new liver, can you push me in the swing?"

But Erika hit an immediate wall. Her insurer, UnitedHealthcare, denied coverage for the transplant, saying it would not be a "promising treatment." She appealed and was rejected again.

The mom who desperately wanted to live looked into Oregon's Death with Dignity program. Erika had written a letter to her daughter months ago to be read after she died. Now she worried Loïe might receive it sooner than Mom had planned:

Dear Loïe,

If you're reading this, I'm probably not on this earth anymore. So please remember this:

I am with you always; even if you can no longer see my face or feel my hands through your hair. I am with you when you look up to the sky and see tiny birds flying free or the stars twinkling in your eyes. I am with you when you feel a perfect, warm breeze upon your sweet face.

Erika wasn't going to give up. Her little girl with bright blue eyes was a constant reminder of all that is precious.

Outraged and heartbroken, Erika wrote a four-page letter to the CEO of UnitedHealth Group, the parent company of UnitedHealthcare (UHC), giving him a piece of her mind about what she felt was a rigged review process, riddled with errors, that determined her life wasn't worth saving.

Weeks passed until the company reached a decision. Despite her plea, the answer was the same: Denied.

Then, last week, an amazing thing happened.

Erika Zak and her husband, Scott Powers, lock hands during a recent hospital visit. The two met 20 years ago.

'My life hangs in the balance'

If it's true that opening your heart, revealing your feelings, unleashes freedom and makes you whole, Erika turned to one of the things she loves most in an effort to save her life. Writing.

It was early April. She sat at her computer, her keyboard clacking. She wasn't going to leave her husband, Scott Powers, and their daughter Loïe behind without trying her damnedest to stay on this Earth for as long as possible.

There was too much at stake.

UnitedHealthcare had overruled her treating physicians and denied the transplant, saying "unproven health services is not a covered benefit." The words burned, like chemo. Her first appeal went nowhere, and she felt trapped in a labyrinth of red tape.

The young mother -- frail from having lost 20 pounds in the past year, her skin and eyes yellow from jaundice -- felt the only way to get a new liver was to plead her case directly to the CEO of UnitedHealth Group, David Wichmann.

Her frame may be tiny, but don't mistake that for weakness. She is one of the strongest women you will ever meet.

As she typed, Erika bared her soul. Of longing to live. Of seeing her daughter grow up. Of the need for "my only option," a liver transplant.

"Given that my life hangs in the balance based on this review," she wrote, "it is unconscionable that it has not been undertaken with the level of competence and professionalism anyone would expect of UHC."

She blasted what she called the "shockingly incompetent manner" in which the country's largest insurance company handled her case. She outlined what she described as a series of errors made in the review process -- ranging from UHC saying her liver failure stems from "chemotherapy toxicity" to an insurance medical director who erroneously said she had "life-threatening lesions."

"Neither are true," she wrote Wichmann. "(UHC's) handling of my case has been plagued by unnecessary delays, incomplete responses, inept scheduling, contradictory statements, and worst of all repeated factual errors regarding my medical history.

"Most importantly, decisions based on inaccurate information and analysis have already delayed my listing and transplant two months."

Loie has been with her mother throughout the process. Erika calls her "my tiniest, most amazing companion."

One review doctor noted she had a "9cm tumor" in her liver, she wrote, apparently unaware that was actually the hole from the ablation surgery resulting in her chronic liver failure.

"I have been doing every single thing I possibly can do to stay alive for these past four years, scratching and clawing by day and praying every night an opportunity like this would come along," Erika wrote. "Now, when the promise of my long-term survival is actually greatest, I need UHC's support more than ever."

She sent the letter via FedEx on April 11.

Her concerns were valid. Her transplant team at the Cleveland Clinic made clear to UHC's appeals unit the primary cause of her liver failure was not from chemo toxicity or cancer, but instead was the result of "a consequence of complications following microwave ablation."

"Of note, what mainly drives the indication of liver transplantation in this case is liver failure and NOT liver metastases from colorectal cancer, which makes the patient's post-transplant oncologic outcome more encouraging," wrote Dr. Federico Aucejo, the director of the Cleveland Clinic's Liver Cancer Program, in an appeal on Erika's behalf on March 6. He did note that she had some chemotoxicity, which was a secondary cause of liver failure.

"The opinion of the experienced Cleveland Clinic multidisciplinary liver transplant committee (is) that liver transplantation would prolong this young patient's life substantially, and that there is NO other treatment alternative that could match this outcome at this point in time."

Two days after sending her letter, Erika and her husband were told the UHC executive team had received it and that her case was undergoing further review.

Several times, the family said it was told a decision would be made by a certain date; those dates came and went without a decision.

As time wore on, Erika grew ill with a high fever and was hospitalized for several days. It was the fifth time she'd been admitted since February 2, the day Cleveland Clinic doctors approved her for a transplant.

On Instagram, she posted an illustration with the words "waiting, waiting, waiting" on a pink backdrop with black crosses.

"Waiting for insurance to approve the only thing that will save me: a liver," she wrote. "Waiting for my liver to fail completely; waiting to die. Waiting to be saved."

Erika has undergone multiple surgeries and faced more than 70 rounds of chemotherapy.

'Wait or die'

More than 100,000 Americans are on wait lists for organ transplants, and every hour someone dies while waiting for the life-saving surgery, said Dr. Andrew Cameron, the chief of transplant surgery at Johns Hopkins and the surgical director of its liver transplant program.

For liver transplants, 20,000 Americans are on the wait list and only 7,000 will receive a new liver in 2018, according to Cameron, who is not connected to Erika's case.

"The lucky few undergo a transformative life-saving procedure," he said. "Those who don't get that lottery ticket wait or die."

Transplant teams at hospitals spend hours upon hours -- months even -- assessing and debating whether a patient is a good candidate for a transplant, Cameron said, typically with more than a dozen doctors weighing in.

It is deeply disturbing, he said, when an insurance company overrules the "decision made by a thoughtful, careful transplant team to utilize one of society's limited resources -- that precious gift to save somebody's life."

The negotiated cost for a liver transplant for an insurance company is roughly $200,000, Cameron said, adding it is "exceedingly rare" for an insurer to deny a transplant.

"That is highly unusual and highly undesirable," Cameron told CNN.

In Cleveland, Dr. Aucejo is trailblazing the field for patients like Erika, having performed the only two transplants in America this century on people suffering from what is called unresectable metastasis in the liver from colorectal cancer.

It's groundbreaking and could prove transformative.

"I hope that we can achieve good results and set precedent," he said.

Dr. Skye Mayo, a surgical oncologist at Oregon Health & Science University, has treated Erika Zak since 2015.

When you're trying such a new approach, Dr. Aucejo said, it can be difficult getting insurers to agree to treatment and he wished getting them aboard could be done "in a more expeditious way."

He explained that in the late 1980s and 1990s, surgeons tried transplants on patients like Erika with "unresectable metastasis in the liver from colorectal cancer," but the "outcomes were not good."

Only 18% of the patients lived past five years, so the transplants were stopped, Dr. Aucejo said. But, he emphasized, most of the bad outcomes were the result of technical complications and post-transplant management, not from the cancer returning. The field of transplants has greatly improved in the decades since, he said.

Doctors in Europe, primarily in Norway, have begun changing the field, he said, finding that about 50-60% of patients with Erika's condition survive a transplant past five years.

That is a substantial difference, he said.

Dr. Mayo, Erika's surgical oncologist in Oregon, said no one at the insurance company reached out to him during the review process "to help explain the facts of her case."

That is troubling, he said, especially when it's one of the most complicated cases a doctor will ever see.

"It is frustrating when it seems that the facts aren't all being considered," Dr. Mayo said.

"Her life now is not limited by her cancer," he said. "It's limited by the fact she will go into liver failure and die within the next several months if she doesn't have a liver transplant."

Erika wrote a note for her daughter if she does not survive: "I am with you always; even if you can no longer see my face or feel my hands through your hair."

When opposites attract

Erika was in the prime of her life. At 34, she'd given birth to her first and only child, Loïe, the little girl who Mom calls "my tiniest, most amazing companion."

She'd been married to the love of her life for four years. She and Scott met in 1998 when he was at Brown University and she was at the Rhode Island School of Design, both in Providence.

The two were polar opposites. He was the MVP of Brown's soccer team and majored in economics. She was into the arts and majored in textile design. He was from the tightly wound East Coast, she from the free-wheeling West Coast.

The connection wasn't immediate, so Erika had a mutual friend slip a tiny drawing to Scott. It contained her phone number; he called it.

Soon they clicked. Scott made her laugh and feel beautiful. Erika saw in him someone who was kind and devoted; in her, he found the woman who he'd always searched for, with a captivating sense of humor and a sailor's mouth.

They tied the knot on Halloween in 2009 in the wine country of Healdsburg, California.

Her career was taking off, too. She was working for Old Navy, choosing and designing the fabrics, prints and plaids for the company's baby and toddler division. While she was pregnant, she was promoted to senior textile designer.

"It was all coming together," she wrote on her blog. "And then, like that, my foundation crumbled."

During the final trimester of her pregnancy, she'd experienced pain in her stomach. It was thought to be nothing more than part of the difficulties of pregnancy. But in the weeks after delivery, the pain grew excruciating and she felt a lump on her side.

On April 8, 2014, she received the awful news -- that she had stage 4 metastatic colon cancer that had spread to her liver. Her daughter was just 3 months old.

"Worst Day Ever" read the headline of her blog.

She had survived cancer once before. At 28, she was diagnosed with thyroid cancer. Her thyroid was removed, and life continued as normal. It was nothing close to a stage 4 diagnosis.

In the years after her colon cancer diagnosis, she blogged about most everything. Of losing her father to Alzheimer's at age 83. Of the pain over two friends' deaths -- including an oncologist she'd met in a cancer support group.

"Have you ever cried and screamed so hard that the blood vessels around your eyes burst?" she wrote.

In her blog posts, she was brutally honest about her cancer and the effects of chemotherapy.

Erika and Scott Powers met in college while they were both in school in Rhode Island.

She'd sit on the shower floor in a fetal position, screaming and sobbing. It was "anguish and pain and longing for my former life and utter disbelief for the war my body was waging on itself," she blogged.

Her fingertips felt like they had been "burned on a hot pan most of the time." Her hands cramped into weird, contorted positions. Her hair was dry and brittle, like straw. Her energy was so drained she felt twice her age.

As a teen, she'd suffered debilitating depression and anxiety that was so bad at times, she said, "I hoped that I could just disappear forever."

"It's funny how afraid I am of that now: disappearing. How much I want to live. How important it feels to be here," she wrote on December 1, 2016, two and half years into her cancer battle.

She would face multiple surgeries and undergo more than 70 rounds of chemo. On February 28, 2017, she wrote:

"This is chemo day. Scream in your pillow day. Hide in the shower day. Lie to your baby day. Tell her you're going to work day. Vials and vials of blood day. Tell your doctor you're angry day. Make your husband cry day. Poison your body day."

On another day, she penned: "Cancer is a slow form of torture. It strips you of dignity; of peace of mind; of stability."

On April 4, 2017, nearly three years to the day of her diagnosis, she and her daughter had a soul-crushing conversation. The cancer had been eradicated from her colon shortly after the diagnosis, but it remained in her liver.

"Mommy, are you going to last?" Loïe asked.

"What do you mean, Loïe?"

"Will you be here forever and ever?" the girl asked.

"I really don't know, babe."

As she awaited word from her insurer about the transplant, Erika said, "I'm mad and grouchy, but I still feel like I have a fighting chance."

Six days later, Erika underwent the ablation surgery at a facility in New York to target two small tumors on her liver. Something went wrong. She ended up with the hole in her liver.

To save her life, surgeons had to block off the veins and arteries going to her liver. The entire central part of her liver died, Dr. Mayo said. Two bags are now attached to her abdomen to drain the bile.

With bile going immediately outside her body, instead of through the liver and her body, Erika was susceptible to extreme sickness and potential fatal bleeds.

"All of those things culminated in what is now liver failure for her," Dr. Mayo said. "She's in this cycle right now where she's losing on a daily basis some of her body's most vital fluids."

The cancer in her liver, meanwhile, was progressing on a path, he said, where "she would die of cancer." She could no longer tolerate any standard form of chemo treatment.

Her doctors in Oregon last fall tried one last treatment to fend off her cancer: a groundbreaking immunotherapy cancer drug called pembrolizumab, known by its brand name Keytruda.

Her sky-high tumor marker levels fell to normal. "She had an incredible response to this new drug," Dr. Mayo said. "I think all of the cancer remaining in her body is dead at this point. What she will die of is liver failure."

With a new liver, he said, her problems with bleeding and high blood pressure could be resolved. Her jaundice would be gone, too.

But transplant surgery is not without major risks.

Most of those who've received a transplant with unresectable metastasis in the liver from colorectal cancer, Cleveland's Dr. Aucejo said, experience a recurrence of cancer within 12 months.

Most of the cancers that return can be treated with standard care, like chemotherapy or surgery, he said, profoundly prolonging their lives.

For a small subset of patients, though, the cancer comes back aggressively and it's not treatable with chemo or surgery, he said. "Unfortunately in that subset of patients, the survival is more dismal."

While it's impossible to predict the outcome, he said, Erika shows "features that may do well." There's no evidence cancer has spread beyond her liver, he said.

Plus, patients who had their colon cancer removed two years or more before the transplant, Dr. Aucejo said, tend do well. Erika had the cancerous portion of her colon removed in 2014: "That's a good indicator."

Dr. Aucejo also emphasized the criteria for transplant qualification is stringent and that Erika shows promise.

"We're talking about distributing limited organs," he said. "Again, we have to be very careful that we're not giving organs to people who are not going to benefit from it when there's people dying with standard indications because there's not enough organs."

Erika Zak comes to the hospital every three weeks for a groundbreaking immunotherapy drug. Her doctors says that without it, she would have died of cancer.

'This is so messed up'

In the days and weeks after Erika fired off her letter to the CEO, her husband, Scott, worked the phones.

He felt lost in an endless loop of delays and broken promises as to when the insurer would reach its decision.

Finally, they were told a decision would come May 2.

Erika couldn't sleep the night before. She pulled out her phone and recorded a message, weeping for much of the video.

"My life is literally in their hands, and every day I feel myself kind of fading away more and more," she says. "I don't want to leave. I don't want to die."

The next day came. Each minute crept by.

Shortly after 2 p.m., Scott's phone rang.

It was their point of contact with UnitedHealthcare.

He had crushing news: Denied.

He explained Erika's case was sent back to the three reviewing doctors. One of them, he said, "changed his decision from 'not promising' to 'promising.'"

However, the other two doctors ruled the transplant not to be promising: "The bottom line is they're upholding that decision."

The doctor who sided in favor of the transplant, their UHC contact told them, was the only one of the three who talked directly with her transplant surgeon.

Scott grew furious. "Honestly, you know that is messed up," he said. "I don't know who you've got to go to, but I would go to someone now and have someone call us, because this is so messed up."

Scott Powers has advocated for his wife since she was first diagnosed with cancer.

Scott pressed for more information. He got little.

"Scott, I know what you've been through," the UHC rep told him. "I know what you're going through."

Erika sat silently for the first 10 minutes of the conservation, absorbing the news and what it meant for her fate. But at those words, it was time to speak up.

"Hey!" she shouted. "This is Erika, and you've never heard from me before. You don't know what we're going through. Because I'm dying."

Through tears, she said, "I need a liver transplant, and I need it now."

The UHC rep confided he "was not hoping for this outcome. I was hoping that I'd have good news."

He suggested Erika and Scott fax over any new information they thought might be relevant. He also acknowledged the delays in recent weeks were not in keeping with the company's policies.

"Someone needs to be accountable for this," he said. "You know, why, when we have these guidelines in place, did we not follow them?

"That needs to be looked into," he said, adding, "I'm not trying to sweep anything under the rug."

He apologized for having to be the bearer of bad news, saying his goal had been to end the day on a positive note.

"Like I said, I wish I had better news."

After more than 30 minutes, he ended with: "Have a good night, OK."

Not the words the couple wanted to hear.

Erika went numb. Heartbroken and angry didn't even begin to describe her feelings.

Scott felt equally distraught. "I just want her to get a liver," he said. "She deserves that."

The CEO never responded -- not by email, phone or letter.

Erika Zak says her will to live is motivated by her daughter, Loïe. Here, they play on the couch as the family dog, Maddie, watches.

A sudden change

Five days later, on Monday, May 7, a surprise call came. Erika and Scott were preparing Loïe for school when Scott's phone rang.

They had spent the weekend trying to figure out their next move, while trying not to focus too much on when Erika might need Death with Dignity. They knew they had one appeal left, and they didn't want to blow it.

They hadn't sent any new information since the last call.

It was their UHC rep on the phone. This time, he had good news: The insurer would cover Erika's transplant.

When Scott heard she'd been approved, he jumped up and down. Erika watched him from across the room.

There was no explanation for the change. They were told to focus on Erika's health and next steps.

Erika called her mother, who unleashed a guttural scream at work.

Loïe has grown excited at the prospect of her mother's transplant. Erika just wants to be able to walk her to school or take her to the playground.

Dr. Mayo was preparing for surgery when he took Scott's call. Elation spread across the Knight Cancer Institute at Oregon Health & Science University where doctors, nurses and staff celebrated.

In Cleveland, Dr. Aucejo heard the welcome news from his transplant coordinator. He'd not spoken with anyone at UHC about the case in the five days since the previous denial.

"They had decided on their own. We hadn't gotten back to them," he said. "I'm happy they ended up sharing our vision."

I had been speaking with Erika and Scott for this story over the last month and had reviewed her medical records extensively. During the May 2 phone call in which Erika was told her transplant had been denied, Scott told the UHC rep that the couple had been speaking with a member of the national news media.

I was on a flight to Oregon when they received the joyous news. "UHC just called and approved Erika. Unreal. Know you're in flight but call whenever," Scott texted.

When we met a couple hours later, Erika's emotions were still raw. She thought this would be her last Mother's Day. Now, suddenly, she has hope for more.

Glancing at her daughter and husband, Erika broke down in tears.

"I can't imagine not being here," she said. "It's not because I keep the family together or anything. It's just the love I have for them."

"Mommy, why are you crying?" Loïe said.

"I'm crying because I love you."

Loïe placed her fingers in her mother's right hand.

"Love you," Loïe said.

As she and Loïe locked hands, the tattoo on Erika's wrist displayed a fitting message: "Be brave."

During her cancer fight, Erika and her twin sister got matching tatoos with one message: "Be brave."

Epilogue

UnitedHealthcare declined to answer CNN's questions about the handling of Erika's case, except to issue this one-sentence statement:

"We had on-going conversations with her husband and contacted him as soon as the decision was made to approve the transplant request."

Even after the approval, Erika said she still wanted to move forward with the story, to speak up for others who've experienced the pain of similar denials. To let them know they're not alone. To encourage them to be their own best advocates.

It can mean the difference between life and death.

"No one should have to fight and work that hard," she said, "especially when I have all these doctors saying it will save my life."

Since the approval, the family has been preparing to move to Cleveland for Erika's surgery and recovery at the Cleveland Clinic. Erika was officially notified Friday morning she was placed on the liver transplant wait list.

It's impossible to know how long the family will be in Cleveland or when the transplant will occur. Transplant candidates are given what is known as a "MELD score," ranging from 6 to 40. Those closest to 40 are given the highest priority.

Erika's MELD score has hovered around 22. If her score is still in that range, Dr. Aucejo said, her transplant could be a few months away.

"But this varies a lot," he said. "There are many variables at play here."

A patient for a liver transplant, he said, is typically hospitalized 7 to 10 days for the procedure, with a recovery time of 4 to 8 weeks before the patient resumes normal activities.

Would Erika have had the transplant by now if the surgery had been approved in February?

Every day Erika says she can feel her body deteriorating. "I don't want to die," she says.

"That is very speculative, at the least," Dr. Aucejo said. "I couldn't say that."

He chose his words carefully, saying it's a "complex dynamic" between hospitals and insurance companies and he doesn't want to upset that balance.

"She's been approved and that's what matters -- and hopefully we can move forward with her transplant."

Dr. Aucejo said he can somewhat understand the insurance company's initial reluctance at coverage because the procedure is so rare for patients with Erika's condition.

"It's a new territory," he told CNN. "I can't blame anybody."

If Erika receives her transplant and succeeds, Dr. Aucejo said, she could help set precedent for many others down the road.

More than anything, she would finally get a chance to be the mother she wants to be.