LOS ANGELES, Aug. 31 -- Stonewalling by the Veterans Administration is putting U.S. cancer surveillance and research in jeopardy, according to many of the researchers involved in those fields.



After decades of sharing data freely and allowing researchers to get in touch with its patients, the agency has been blocking such activity for the past several years, according to Dennis Deapen, Dr.PH., of the Los Angeles Cancer Surveillance Program and the University of Southern California.



The result, Dr. Deapen said, is that California state data on cancer incidence rates are being skewed. And that, he said, is likely to have serious effects on national data.



The California Cancer Surveillance Program has seen a sharp drop in the agency's reporting of new cases to Californian cancer registries beginning in late 2004 -- from 3,000 cases in 2003 to almost none by the end of 2005, according to an article in the September issue of Lancet Oncology.



But the problem is not restricted to California, according to Holly Howe, Ph.D., of the North American Association of Central Cancer Registries (NAACCR) in Springfield, Ill.



"California has been very energetic in evaluating the impact of the loss of VA cases on completeness and the ability to produce accurate incidence data," Dr. Howe said.



"But it's not just California -- it's nearly every state," she said.



However, California and Florida -- where VA reporting of cancer cases has also been blocked -- have large populations of veterans and large VA medical facilities, she said.



Missing data from those two states has the potential to warp national estimates, she said.



Lancet Oncology quoted Raye Ann Dorn, the VA's national coordinator of cancer programs, as saying that only California and Florida were withholding data, mainly because of privacy concerns.



Dorn was not immediately available for comment on the eve of the Labor Day weekend.



Lancet Oncology said other VA officials pointed out that of the 130 medical centers that collect cancer data, only 29 withheld cases from state cancer registries in 2006.



But the journal also said that, according to CDC data, VA centers in seven states are not reporting cancer cases and in six others, at least one VA facility is not reporting.



All told, "40 000 to 70 000 cases are potentially missed nationally each year," the journal quoted a CDC spokesman.



Dr. Howe said her organization and others have been trying to persuade the VA to resume wholehearted data-sharing, but with little success. "We've been trying to solve this for over five years," she said.



Asked if she knows what's behind the policy, Dr. Howe said flatly: "No."



Representatives of a "whole cadre of associations" -- including NAACCR, the CDC, the American Cancer Society, and the National Cancer Institute -- met in early August to discuss the issue, Dr. Deapen said.



He said the VA position has two main effects.



The skewing of national and state cancer incidence rates, he said, is "correctable."



"The VA still has the data," he said. "They could hand it out and then we could correct incidence rate data."



What is "incorrectable," he said, is the effect the data blockade could have on research.



Dr. Deapen said, for example, that researchers investigating the causes of a particular type of cancer might be misled if they were not aware of a cluster of cases being treated in VA hospitals.



"Once that study is done, (the researcher) doesn't get to go back and do it over," Dr. Deapen said. Research during this period "will forever require an asterisk" to remind other researchers that it might not be correct.



But even when states get VA data, some cases may slip through the cracks under a related VA policy that forbids interstate data-sharing, he said.

For instance, he said, it's common for veterans in some eastern states to seek treatment in neighboring states.



The host state doesn't count them, because they live next door. And the VA refuses to notify the home state or let the host state do so, so that some cases are simply never counted, Dr. Deapen said.



Several of the cancer registries that are being locked out of VA data take part in the Surveillance Epidemiology and End Results (SEER) program, according to Brenda Edwards, Ph.D., of the National Cancer Institute, which operates the database, a valued resource for epidemiological research.



"This will significantly impact reporting in SEER," Dr. Edwards told Lancet Oncology.



The collection of disease incidence data is a state responsibility, Dr. Deapen said, but the VA -- as a federal agency -- is under no obligation to comply with state laws.



Nonetheless, for years the VA voluntarily shared its data and allowed access to patients, he said.



"We had it right and we were doing a good job," Dr. Deapen said. "Now we need to get back on track."