IHC Usage Growing
“The paper confirms what I already knew,” said Whitney High, MD, JD, who was not involved with the study and was asked to comment on the results. “Use of IHC in dermatopathology has increased substantially, and probably will continue to increase over time.” The societal burden of IHC costs represents a legitimate concern, said Dr. High, professor of dermatology and pathology and director of dermatopathology at the University of Colorado, Aurora.
“However,” he told this news organization, “the histologic diagnosis of melanoma is sometimes substantially subjective — and all physicians, including pathologists, even though they are not providing care in the physical presence of the patient, are fiduciaries.” If an IHC stain would meaningfully improve a patient’s care, he said, physicians should attempt to provide it, unless strictly disallowed by a payer. Controlling medical-care costs might be better left to professional societies to guide care standards over time, he noted.
Dr. High
Dr. Whitney High
IHC has the potential to improve the accuracy and reliability of melanoma assessments by providing additional data, said Dr. High.“To this end, disallowing the use of immunostains simply due to cost, without substantial evidence, has the potential to alter diagnoses and impact care negatively.” This is particularly true for melanoma, he said, where “finding even one additional melanoma with IHC has life-altering consequences for that patient.”
How IHC might impact melanoma overdiagnosis remains unclear without additional study. IHC might allow dermatologists to avoid diagnosing melanoma in borderline cases unsupported by IHC, explained Dr. High, or false-positive results could further fuel melanoma overdiagnosis.
Limitations of the IHC paper included an inability to determine whether IHC improved outcomes. Additional shortcomings included use of a SEER-specific older population. And because CPT codes are not site-specific, some samples may have come from surgical margins or non-skin locations.
Study authors reported receiving grants from the National Cancer Institute (NCI) during the conduct of the study. The study was funded by the University of California, Los Angeles (UCLA) National Clinician Scholars Program, the UCLA Department of Pathology, the California Department of Public Health, and the NCI. Dr. High reports no relevant financial interests.