A new study on pediatric Hodgkin lymphoma from the UM Sylvester Comprehensive Cancer Center has found that African-American children and teenagers diagnosed with the disease have substantially inferior survival rates than their white and Hispanic counterparts.
But they fare even worse in Florida than on a national level.
Lymphoma cancer – where white blood cells in the immune system grow abnormally – is the third most common form of cancer in children and teenagers. Hodgkin lymphoma makes up almost half of all lymphoma diagnoses and is highly curable. According to the American Cancer Society, the first stage of the disease has a 90 percent five-year survival rate.
Published today in Pediatric Blood & Cancer, the two-year study is the largest to investigate survival disparities as a result of race and ethnicity for the disease. Using Florida-specific and national databases, it surveyed more than 7,800 patients age 21 and under.
Looking at the Florida Cancer Data System (FCDS), the study found that 33 percent of African-American children survived the disease 25 years after diagnosis compared to 49.2 percent of whites and 44.7 percent of Hispanics. The National Institute of Health’s Surveillance, Epidemiology, and End Results Program (SEER) database showed 72 percent of African-American children surviving the disease compared to 82 percent of whites and Hispanics.
Dr. Joseph Panoff, a radiation oncologist at Sylvester and the lead author of the study, said that while the two data sets are not directly comparable, the finding is still noteworthy. His team does not know why African-Americans in Florida have significantly lower survival rates.
“The state difference was definitely unexpected,” he said. “We don’t know the reasons.”
Although the study did not include socioeconomic data, Panoff hypothesized that the national discrepancies could be connected to poorer access to healthcare among African Americans.
“Access to medical care is a huge issue,” he said. “And with more health care available with the Affordable Health Care Act, it will be interesting to see if the disparities hold in the next decades.”
Dr. Celeste Bello, an associate professor at the Moffitt Cancer Center in Tampa who specializes in adult lymphoma, agreed. She added that discrepancies in survival rates are also seen in breast, colon and lung cancer.
“Usually, with most cancer, it’s due to socioeconomic factors, like income, living condition, family access to healthcare, which unfortunately seems to be not as available to minorities, so that’s why we usually see the disparities,” Bello said. “In things like lymphomas, it seems to be more based on accessibility to healthcare.”
She added that in the United States, adults and adolescents of higher socioeconomic status are more likely to contract the disease, for reasons still unclear.
“Historically, it seems that people with higher socioeconomic status have a higher rate of Hodgkins, so it’s a weird cancer because we don’t see it associated with poor socioeconomic status,” Bello said.
Another discrepancy the study noted was the difference between the Florida and national survival rates among the general population. The national database showed a five-year survival rate at 93.5 percent, while the Florida database indicated a survival rate of 84.2 percent. According to Panoff, while the two data sets are not directly comparable, “it seems significant.”
Using the national database, the study also looked at “disease-specific survival” (DSS), or the frequency that Hodgkin recurred among patients. It found that while Hispanics showed equal survival rates as whites, the disease recurred more frequently among Hispanic males than white males. Accounting for this, the study states, “... we hypothesize that the Hispanic population may have worse follow up, poorer access to healthcare, and language barriers that cumulate into worse DSS.”
Notably, Panoff’s team found that African-Americans in Florida received less radiation to treat the disease than Hispanic and white patients, with African-Americans receiving 32.2%, Hispanics 43.5% and whites 45.5%. Nationally, African-Americans and Hispanics received less radiation than white patients.
“Blacks should have received equal and more therapy since they presented more advanced stages of the disease,” said Panoff. “If you received radiation you had better overall survival.”
A 2008 study published by the St. Jude Children's Research Hospital in Memphis, TN reported equivalent five-year survival rates among African-American and white patients with pediatric Hodgkin lymphoma. It examined 327 patients at one institution, and Panoff said that his team is “confident our results are more accurate because of our larger numbers.”
But regardless, Panoff believes more research must be done to explain the racial disparities.
“I think that it opens the door to examining racial and ethnic disparity in the state of Florida as well as comparing cancer outcomes with the rest of the country and Florida,” he said. “I think that it also sets the stage to determine the efficacy of the Affordable Health Care Act in the future.”