Trends in Survival after Diagnosis with Hematologic Malignancy in Adolescence or Young Adulthood in the United States, 1981- 2005

Background: There are few population based studies of long-term survival of adolescents and young adults (AYA) with hematologic malignancies, mostly pertaining to patients diagnosed in the 1990s or earlier. Traditionally, survival in AYA with hematologic malignancies has been worse than survival for children with similar malignancies. Here, we use period analysis to obtain up-to-date information on survival expectations of AYA diagnosed with hematologic malignancies through the early 21st century.

Methods: Period analysis was used to calculate 5- and 10-year relative survival for AYA aged 15–24 diagnosed with hematologic malignancies for five calendar periods from 1981–85 to 2001–2005, using data from the Surveillance, Epidemiology, and End Results (SEER) database. Results: Data from 9836 patients aged 15–24 included in the SEER database who were diagnosed with Hodgkin’s lymphoma (HL), non-Hodgkin lymphoma (NHL), acute lymphoblastic leukemia (ALL), acute myeloblastic leukemia (AML), and chronic myelocytic leukemia (CML) were analyzed. HL was the most common malignancy, accounting for about 50% of all hematologic maligancies in each calendar period examined.

Survival strongly improved for each of the five hematologic malignancies. Increases in 10-year relative survival were as follows: HL, from 80.4 to 93.4%; NHL, from 55.6 to 76.2%; ALL, from 30.5 to 52.1%; AML, from 15.2 to 45.1%; CML, from 0 to 74.5% (p<0.0001 in all cases, see table). However, while survival improved steadily throughout the period examined for the lymphomas and CML, survival was stable during the late 1990s and early 21st century for the acute leukemias. Survival has not improved for AML since 1990–95 or for ALL since 1996–2000 (see table).

Discussion: Survival expectations for AYA with hematologic malignancies have strongly improved since the 1980s. However, with the exception of HL, survival rates have not reached the levels observed for children diagnosed with the same malignancies. In particular, 10-year survival in children aged 10–14 with ALL was over 75% for the 2000–04 period1 compared to about 50% for AYA in 2001–05. Similarly, 10-year survival for children aged 0–14 diagnosed with acute non-lymphoblastic leukemia was about 60% in the 2000–04 period compared with less than 50% for AYA with AML in the 2001–05 period. Some caution must be used when comparing survival in AYA versus in children since survival estimates for children are for absolute survival, while those for AYA are for relative survival. However, relative survival in children and AYA is close to 100%, making the comparison relatively straightforward.

Furthermore, survival estimates for the acute leukemias have not improved since the 1990s while survival for children continued to improve during the early 21st century. Reasons for the poorer survival observed may include differences in the biology of the malignancies, poorer compliance in AYA, differences in treatment protocols in children versus AYA, lower availability of clinical trials in AYA than in children, and low rates of health insurance in AYA patients, particularly after age 18. Further examination of the reasons for the poorer outcomes observed for AYA with acute leukemias may clarify this issue.

¹ Pulte D, Gondos A, Brenner H. Trends in 5- and 10-year survival after diagnosis with childhood hematologic malignancies in the United States, 1990–2004. Accepted JNCI 7/08.

Table: 10-year relative survival 1981–85 to 2001–05 by hematologic malignancy