Two new studies offer insights into leukemia survival rates in the United States. From 2000 to 2014, a drop in mortality among children spurred a rise in 5-year leukemia survival rates among patients aged 0-24. But adolescents and young adults who survive 5 years after diagnosis face an ongoing higher risk of death, recent research revealed, and their long-term survival is lower compared to that of the general population.
"Outcomes are improving. However, additional efforts, support, and resources are needed to further improve short- and long-term survival for acute leukemia survivors. Targeted efforts focused on populations that face greater disparities in their survival are needed to move the needle faster," Michael Roth, MD, codirector of the Adolescent and Young Adult Oncology Program at the University of Texas M.D. Anderson Cancer Center, said in an interview.
In one study, released in The Lancet Child & Adolescent Health, an international team of researchers tracked survival outcomes from various types of leukemia in 61 nations. The study focused on the years 2000-2014 and followed patients aged 0-24.
"Age-standardized 5-year net survival in children, adolescents, and young adults for all leukemias combined during 2010-14 varied widely, ranging from 46% in Mexico to more than 85% in Canada, Cyprus, Belgium, Denmark, Finland, and Australia," the researchers wrote. "Throughout 2000-14, survival from all leukemias combined remained consistently higher for children than adolescents and young adults, and minimal improvement was seen for adolescents and young adults in most countries."
The U.S. data came from 41 states that cover 86% of the nation's population, lead author Naomi Ssenyonga, a research fellow at London School of Hygiene & Tropical Medicine, said in an interview.
The 5-year survival rate for acute lymphoid leukemia (ALL) rose from 80% during 2000-2004 to 86% during 2010-2014. Survival in patients with acute myeloid leukemia (AML) was lower than for other subtypes: 66% in 2010-2014 vs. 57% in 2000-2004.
In regard to all leukemias, "we noted a steady increase in the U.S. of 6 percentage points in 5-year survival, up from 77% for patients diagnosed during 2000-2004 to 83% for those diagnosed during 2010-2014," Ms. Ssenyonga said. "The gains were largely driven by the improvements seen among children."
Why haven't adolescents and young adults gained as much ground in survival?
"They often have unique clinical needs," Ms. Ssenyonga said. "Over the past few years, adolescents and young adults with leukemia in some parts of the world, including the U.S., have increasingly been treated under pediatric protocols. This has led to higher survival. However, this approach has not been adopted consistently, and survival for adolescents and young adults with leukemia is still generally lower than survival for children."
Gwen Nichols, MD, chief medical officer of the Leukemia & Lymphoma Society, agreed that pediatric treatment protocols hold promise as treatments for young adults. However, "because we arbitrarily set an age cutoff for being an adult, many of these patients are treated by an adult [nonpediatric] hematologist/oncologist, and some patients in the 20-39 age group do not receive the more intensive treatment regimens given to children," she said in an interview.
In another study, published in Cancer Epidemiology, Biomarkers, & Prevention, M.D. Anderson Cancer Center's Roth and colleagues tracked 1,938 patients with ALL and 2,350 with AML who were diagnosed at ages 15-39 from 1980 to 2009. All lived at least 5 years after diagnosis. In both groups, about 58% were White, and most of the rest were Hispanic. The median age of diagnosis for ALL was 23 (range: 15-39) and 28 years for AML (range: 15-39).
"For ALL, 10-year survival for those diagnosed in the 1980s, 1990s, and 2000s was 83%, 88%, and 88%, respectively," the researchers reported. "Ten-year survival for AML was 82%, 90%, and 90% for those diagnosed in the 1980s, 1990s, and 2000s, respectively."
"Early mortality within 10 years of diagnosis was mostly secondary to leukemia progressing or recurring. We believe that later mortality is secondary to the development of late side effects from their cancer treatment," Roth said.
He noted that many adolescents and young adults with ALL or AML receive stem-cell transplants. "This treatment approach is effective. However, it is associated with short- and long-term toxicity that impacts patients' health for many years after treatment."
Indeed, up to 80% of acute leukemia survivors have significant health complications after therapy, said the Leukemia & Lymphoma Society's Nichols, who wasn't surprised by the findings. According to the society, "even when treatments are effective, more than 70% of childhood cancer survivors have a chronic health condition and 42% have a severe, disabling or life-threatening condition 30 years after diagnosis."
"It would be interesting to understand the male predominance better," she added, noting that the study found that male patients had worse long-term survival than females (survival time ratio: 0.61, 95% confidence interval, 0.45-0.82). "While it is tempting to suggest it is due to difference in cardiac disease, I am not aware of data to support why there is this survival difference."
What's next? "In ALL, we now have a number of new modalities to treat high-risk and relapsed disease such as antibodies and CAR-T," Nichols said. "We anticipate that 5-year survival can improve utilizing these modalities due to getting more patients into remission, hopefully while reducing chemotherapeutic toxicity."
Nichol's also highlighted the society's new genomic-led Pediatric Acute Leukemia (PedAL) Master Clinical Trial, which began enrolling children with acute leukemia in the United States and Canada this year, in an effort to transform medicine's traditional high-level chemotherapy strategy to their care. The project was launched in collaboration with the National Cancer Institute, Children's Oncology Group, and the European Pediatric Acute Leukemia Foundation.
As part of the screening process, the biology of each child's cancer will be identified, and families will be encouraged to enroll them in appropriate targeted therapy trials.
"Until we are able to decrease the toxicity of leukemia regimens, we won't see a dramatic shift in late effects and thus in morbidity and mortality," Nichols said. "The trial is an effort to test newer, less toxic regimens to begin to change that cycle."
The 5-year survival study was funded by Children with Cancer UK, Institut National du Cancer, La Ligue Contre le Cancer, Centers for Disease Control and Prevention, Swiss Re, Swiss Cancer Research foundation, Swiss Cancer League, Rossy Family Foundation, National Cancer Institute, and the American Cancer Society. One author reports a grant from Macmillan Cancer Support, consultancy fees from Pfizer, and unsolicited small gifts from Moondance Cancer Initiative for philanthropic work. The other authors report no disclosures.
The long-term survival study was funded by the National Cancer Institute, the Archer Foundation and LyondellBasell Industries. Roth reports no disclosures; other authors report various disclosures. Nichols reports no disclosures.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.
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