TAMPA — Over five months, Daniel Witt endured high doses of chemotherapy to shrink the cancer in his abdomen. He vomited and trembled; he grew bony and fragile. He needed his father to help him up the stairs, his wife to help him out of the chair.
But the tumor, diagnosed as advanced melanoma, kept growing.
His doctors at Moffitt Cancer Center told him there were no options left. But in October 2012, Witt flew to M.D. Anderson Cancer Center in Texas to enroll in a clinical trial for melanoma patients.
Doctors there delivered startling news: They didn't think he had melanoma. They believed he had another cancer, sarcoma.
A second biopsy back at Moffitt proved M.D. Anderson right. For nearly a year, Witt had the wrong diagnosis and, consequently, the wrong treatment.
A 13-year deputy at the Hillsborough County Sheriff's Office, Witt returned to Moffitt to begin sarcoma treatment but died in April at age 34.
His story highlights a little-discussed but startlingly common problem: misdiagnoses.
Diagnoses that are wrong, missed or delayed affect up to 20 percent of all medical cases, according to an estimate published last year in the Journal of the American Medical Association. That's a higher rate than drug errors or wrong-site surgeries, which get more attention.
Cancer biopsies are wrong between 2 and 5 percent of the time, said Dr. David Newman-Toker, a Johns Hopkins School of Medicine neurologist who studies diagnostic errors.
A month before Witt died, he and wife, Erin, filed a notice in Hillsborough County Circuit Court that they intended to sue Moffitt as well as St. Joseph's Hospital and Florida Hospital Tampa, which treated him earlier. Both hospitals have settled for undisclosed sums.
Moffitt officials declined to comment. The Witts' attorney, David Tirella, said his medical expert will testify that if the sarcoma had been diagnosed in late 2011, Witt could have survived.
Diagnostic errors were the leading type of mistake cited over 25 years of successful malpractice claims, according to a study last year co-written by Newman-Toker.
Growing evidence suggests the issue warrants more attention from researchers as well as patients, who may want to seek second opinions on their diagnoses before beginning treatment, Newman-Toker said.
"It's something that's been ignored," he said.
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Misdiagnosis can happen for a variety of reasons, Newman-Toker said. Primary care doctors, pushed for time, may not get a sufficiently detailed picture of patients' symptoms. Physicians can focus too heavily on one disease without considering alternatives, particularly those they rarely have seen. Pathologists and radiologists can misread slides or scans.
Daniel Witt's medical history pointed toward a melanoma diagnosis. He survived advanced melanoma in 2005, followed by a recurrence in 2006. Both times, he was treated at Moffitt.
In mid 2011, he began complaining of stomach pain. He was treated at Florida Hospital Tampa and St. Joseph's. His attorney declined to comment on those hospitals, but neither had given Witt the proper diagnosis before he entered Moffitt in December 2011.
A CT scan that month showed an 8-centimeter tumor — a little larger than a tennis ball — in his abdomen, according to his medical records.
"He was very emotional," said his widow, Erin, 31. "You could see on his face that it was all happening again."
The team at Moffitt discussed Witt's case at a hospital tumor review board, which recommended a biopsy "to confirm the diagnosis of metastatic melanoma," his records say.
Days later, a Moffitt pathologist issued a report saying the tiny pieces of soft tissue collected were metastatic melanoma. Witt started an aggressive combination of chemotherapy and immunotherapy, a regimen used on advanced melanoma patients. Surgery was not an option at that point, they said, because the tumor was tangled with arteries.
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By late summer 2012, the tumor nearly tripled in size. When the Witts arrived at M.D. Anderson, his swollen belly made him appear seven months pregnant, Erin said.
Doctors there looked at the same biopsy slides examined at Moffitt and saw something else.
"They were like, 'We think you have sarcoma,' " said Erin, "and we're like, 'What's sarcoma?' We were kind of excited. We were like, 'Oh, good, there are more options now.' "
Back at Moffitt, the Witts insisted on another biopsy. The lab later agreed it was sarcoma.
Erin said Witt's medical oncologist, Dr. Jeffrey Weber, told them that pathologists compared the 2011 biopsy to Witt's melanoma sample from 2005 and concluded they were the same type of cancer. She said he told them Witt's 2011 biopsy was riddled with dead tissue, making it difficult to interpret on its own.
"I said, 'You used the previous biopsy?' " she said. "If they didn't get enough (useable) tissue, why weren't we told?"
Weber did not respond to a request for comment. Pathologists not connected to the case said it's typical to compare new samples with old ones to see if a particular cancer has returned.
"It's standard practice," said Dr. John Pfeifer, vice chairman for clinical affairs in the department of pathology at Washington University School of Medicine in St. Louis. But he added: "Just because someone has one type of cancer doesn't mean they'll have it again."
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But his own history isn't the only factor that may have contributed to Witt's misdiagnosis. Sarcoma is such a rare cancer among adults, "it can be a head scratcher for the pathologist," said Dr. Mark Thornton, founder of the Sarcoma Foundation of America.
And under a microscope, pathologists say, melanoma can look much like several cancers, including sarcoma.
"Melanoma is well known for being a pitfall where you can see multiple patterns," said Dr. Barbara McKenna, professor of pathology at the University of Michigan.
She said a technique called staining, which reveals proteins associated with certain cancers, can shore up the diagnosis. Witt's records suggest staining was performed, but it's unclear what it revealed.
For sarcoma patients, surgery is typically the first step as long as the tumor is under 10 centimeters, Thornton said.
Tirella said the family doesn't expect a windfall from the suit. State law limits judgments against institutions like the nationally recognized Moffitt to $300,000.
Witt, who left behind four young children, was a devout Christian who didn't want to think of the 10 months of misdiagnosis as a waste, his widow said. Rather he saw the fact that he could share his faith with two of his nurses as evidence of God's grace.
But in their Wesley Chapel home one recent afternoon, looking at the sofa where she slept every night to watch over Witt in his recliner, Erin lamented the lost months.
"It was just a waste of time," she said. "He didn't even need it, and that was so much poison for him."