Questions Linger About McCain's Prognosis After Skin Cancer
Saturday, October 18, 2008
In May, the presidential campaign of 72-year-old cancer survivor John McCain tried to put to rest doubts about his health by allowing a few reporters to inspect his medical records, but the effort has failed to quell questions about his odds of surviving an eight-year tenure in the White House.
One loosely organized group of physicians has been claiming in Web-based videos, op-ed columns and newspaper ads that McCain's risk of dying from a recurrence of the skin cancer he had treated eight years ago may be as high as 60 percent.
However, data on cancer survival rates compiled by the federal government suggest that people in McCain's situation have no more than a 10 percent chance of dying from melanoma over the next decade.
The key to the favorable prognosis is that McCain has already survived eight years without a recurrence. Even if the cancer was more serious in 2000 than his doctors judged, the fact that he is alive today suggests it had not spread by the time it was removed on Aug. 19, 2000, at the Mayo Clinic's campus in Scottsdale, Ariz.
The McCain campaign has rejected releasing additional records. A campaign spokeswoman, Jill Hazelbaker, said in an e-mail that letting reporters look at 1,173 pages of medical documents "was an unprecedented level of disclosure. . . . It was certainly more significant than the one-page doctor's note [Democratic candidate Barack] Obama released!"
The gist of the critique is that McCain's cancer was more advanced than his physicians concluded and that the chance of recurrence is consequently higher. Melanoma that spreads widely through the body -- "metastasizes," in medical parlance -- is rapidly fatal.
The effort to learn more about McCain's health gained steam after he chose Alaska Gov. Sarah Palin as his running mate. More than 2,700 physicians signed a full-page ad in the New York Times on Oct. 3 calling for a "full, public release" of the candidate's medical records. Others urged that microscopic slides of tissue removed before and during his operation be made available for review by independent pathologists.
"Voters need to know who is most likely to be running the country in 2010 if Senator McCain is elected in 2008," Wendy Epstein, a New York dermatologist and Obama supporter, wrote in an eight-page analysis of the senator's risk circulating on the Internet.
She and some other critics believe the odds of McCain surviving 10 years after his surgery is 36 to 56 percent. The senator's physicians, while eschewing precise predictions, have said that his risk of developing metastatic melanoma is in the "single digits."
Data from the Surveillance, Epidemiology and End Results (SEER) Program of the National Institutes of Health support the more optimistic view. The SEER database is drawn from representative areas that together contain about one-quarter of the population. It is considered the most authoritative compendium of American cancer patients' survival rates.
At the request of The Washington Post, biostatisticians at the National Cancer Institute, where SEER is housed, "interrogated" the database with McCain's demographic variables. None of the data are linked to patients' names.
The melanoma patients in SEER are categorized by whether the disease was "localized," "regional" or "distant" at the time it was found. This staging system is simpler than the one currently used by dermatologists, who divide patients into Stages I to IV, and then into many subcategories.
McCain's physicians concluded after some debate that he was Stage IIa, which would put him in SEER's localized category. Epstein and many of the doctors calling for the release of his records say McCain was Stage IIIb, which falls into SEER's regional group.
The SEER data show that a white male whose cancer was diagnosed in his early 60s and who is now an eight-year survivor of melanoma has a 2 percent risk of dying of the disease in the next five years if the original tumor was localized, and a 4 percent risk if it was regional.
The first estimate was based on the experiences of 1,481 people and has an error range of plus or minus 0.4 percent. The second was drawn from only 83 people and has more uncertainty -- 2.6 percent.
If one looks out 10 years from now, a person with McCain's experience has a 4 percent probability of dying if the tumor was localized and 10 percent if it was regional. The error ranges of those estimates are 0.7 and 5.1 percent, respectively.
Someone with McCain's variables can, of course, die of other causes. According to SEER, such a person has an 85 percent overall chance of surviving five years and a 66 percent chance of living 10 years, regardless of whether the cancer was localized or regional.
In their analysis, many of the critiquing doctors point to a comment made by two pathologists at the Armed Forces Institute of Pathology in Washington who were asked by the Mayo Clinic to look at microscopic slides from McCain's biopsy.
Those doctors said the tissue's appearance "is highly suggestive of a metastasis of malignant melanoma and may represent a satellite metastasis."
A satellite metastasis is an island of cancer that has spread from a nearby tumor. In terms of risk, it is equivalent to finding cancer in the nearby lymph nodes, which makes the disease regional and no longer localized.
The Mayo Clinic doctors concluded that McCain did not have satellite metastases. However, to be safe, they did a much more extensive operation than is usual for purely localized disease, removing more than 30 lymph nodes from McCain's face. No cancer was found in any of them.
Research editor Alice Crites contributed to this report.