Burkitt Lymphoma Survival Outcomes Improve for Younger Patients
According to a new study published in the journal Cancer, the survival outcome of patients with Burkitt lymphoma has improved substantially over the past decade, with notable exceptions. To help doctors and researchers better understand who responds well to treatment and who does not, the study authors used their findings to create a stratified risk score of patient prognosis.
Burkitt lymphoma is not a common lymphoma but it is especially aggressive. The apparent progress doctors have made with this malignancy during the last 2 decades has come with little guidance about how to treat different patients or what outcomes to expect. The same regimen of intensive chemotherapy and the monoclonal antibody rituximab (Rituxan) is recommended for most patients with Burkitt lymphoma.
“There was little available for Burkitt lymphoma in terms of prognostic factors, indicators, or scoring,” said study lead author Jorge Castillo, MD, Assistant Professor of Medicine at the Warren Alpert Medical School of Brown University and a hematology/oncology specialist at Rhode Island Hospital.
Study Details
To understand prognosis of patients better, Dr. Castillo and colleagues looked at 11 years of patient records in the Surveillance, Epidemiology, and End Results (SEER) database and analyzed survival rates among 2,284 patients by factors including age, race, stage of the cancer at diagnosis, and disease site.
The researchers found that although survival rates have risen substantially overall, patients who are older than 60, black, or whose cancer were diagnosed at a late stage had worse survival. Using these risk factors, the researchers created a new risk score that allowed them to make meaningful distinctions about prognosis.
Improved Survival for Younger Patients
Age played a major prognostic role, Dr. Castillo and his coauthors found. Their analysis revealed that patients over 80 years old had a nearly fivefold risk of dying from the cancer as people aged 20 to 39. Patients aged 60 to 79 had twice the risk of dying as the youngest patients, and those aged 40 to 59 had a risk 1.5 times greater than those aged 20 to 39.
Risk of death climbed similarly with the stage of cancer. Patients with stage IV disease had a 2.4 times greater risk of dying than those with stage I disease. Patients with stage III disease had a 1.5 times greater risk.
Race was also a factor, although to a lesser degree. Hispanics and whites had similar risk levels but black people, who accounted for 9.3% of the patients, had a 1.6 times higher risk of death.
These same risk factors were also evident in whether patients had seen improved survival over time, for instance as intensive chemotherapy and later rituximab have gained prevalence.
In 1998, the survival rate was fairly uniform for all age groups, Dr. Castillo and his colleagues found: 34.7% overall. As of 2007, survival had risen to 62.1% for the youngest adult patients, but survival for patients over the age of 60 increased only slightly for a survival rate of 43.5%.
Among patients of different ethnic backgrounds, a similarly widening gap was observed. Survival among non-Hispanic whites rose from 31.7% to 50.9% and among Hispanics from 22.7% to 47.1%. Among blacks, however, survival has remained low and flat: from 28.8% in 1998 to 29.9% in 2007.
Dr. Castillo said he does not know with certainty from the study or from the medical literature why black patients fare relatively poorly, but noted that this study the disparity in survival rates was independent of socioeconomic status.
Prognostic Score
Using the significant risk factors they discovered, Dr. Castillo and coauthors Eric Winer, MD, also of Rhode Island Hospital, and Adam Olszewski, MD, of Memorial Hospital in Pawtucket, Rhode Island, created the risk score in which being 40 to 59 years old or being black adds one point; being age 60 to 79 or having a stage III or IV diagnosis adds two points, and age over 80 adds four points. Doing so separated the 2,284 patients into roughly equal groups with a wide range of 5-year relative survival rates.
Among the groups, those with a score of zero to one (low risk) had a 71% relative survival rate. A score of two (low-intermediate risk) reduced the rate to 55%, and a score of three (high-intermediate risk) had a 41% relative survival. For those with a score of four or higher (high risk), the relative survival rate was only 29%.
Dr. Castillo said there are several applications for the score, including helping doctors, patients, and their families understand what to expect and to evaluate whether intensive regimens of difficult therapy are truly desirable, compared to possible alternatives. The score can also inform researchers about how to design clinical trials of treatments of the disease.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
