ATLANTA — A review of more than 60,000 melanoma patients found that they were more likely to have a sentinel node biopsy and receive adjuvant therapy with a biologic response modifier if they had commercial insurance and were treated at a teaching hospital in a geographic area where these options were more often used.
Sentinel node biopsies were performed significantly more often in the mountain states, compared with all other areas of the United States. Patients in New England were least likely to have the procedure (odds ratio 0.378).
Use of biologic response modifiers such as interferon-α was most prevalent in the west north central states stretching from North Dakota and Minnesota south to Kansas and Missouri. They were used least often in the area directly south, however: the west south central states of Oklahoma, Arkansas, Texas, and Louisiana (odds ratio 0.395).
Patients in the Mid-Atlantic, south Atlantic, and east south central states also were significantly less likely to be treated with an adjuvant biologic response modifier (odds ratios 0.765, 0.786, and 0.465, respectively).
“It turns out that where patients are treated has a large association with how they are treated,” Dr. Julie R. Lange said in an interview at the annual meeting of the American Society of Clinical Oncology, where she presented the results in a poster.
Dr. Lange, of the department of surgery at Johns Hopkins University in Baltimore, extracted the data from the National Cancer Data Base maintained by the American Cancer Society and the American College of Surgeons.
The study used U.S. Census regions to divide the patients by geographic area. Dr. Lange said the database did not distinguish interferon use from other immune therapies in the biologic response modifier category.
She and her colleagues found 61,251 patients, aged 1–69 years, who had surgery for stage I or II melanoma between 1998 and 2002. Among these patients, 36% had a sentinel node biopsy. The procedure was done in 56% of patients with T3 tumors, 46% with T2 tumors, and 42% with T4 tumors, but only 13% of patients with T1 tumors.
The investigators found 10,790 patients who had surgery for node-positive melanoma between 1994 and 2003. More than a third, 38%, were treated with a biologic response modifier: 37% of patients with one positive node and 39% of those with two or more positive nodes.
Sentinel node biopsies and use of biologic therapies were significantly more common at teaching hospitals than at community hospitals and other types of facilities.
Although both of the therapies were most often used in patients with commercial insurance, the difference was not significant for patients insured by a health maintenance organization or managed care. It was significant for those covered by Medicaid or Medicare and those who were covered by other types of insurance or uninsured.
Gender and race did not appear to play a role in whether the patients received either a sentinel node biopsy or a biologic therapy.
Both the biopsy and this kind of treatment were most common in patients under the age of 25. All older patients were significantly less likely to receive a biologic, only patients aged 51–69 years were significantly less likely to have a sentinel node biopsy.
Era of treatment also seemed to have an effect. Patients treated after the year 2000 were more likely to have a sentinel node biopsy than were those treated earlier. Conversely, patients were less likely to receive a biologic therapy if treated after 1998.
“It is not really clear why disparities exist,” Dr. Lange said. “It is one of those studies that raise a lot of questions.”