Risk of second malignant neoplasms after childhood leukemia and lymphoma: an international study.
BACKGROUND
Survivors of childhood leukemia and lymphoma experience high risks of second malignant neoplasms. We quantified such risk using a large dataset from 13 population-based cancer registries.


METHODS
The registries provided individual data on cases of leukemia, Hodgkin lymphoma, and non-Hodgkin lymphoma occurring in children aged 0-14 years and on subsequent second malignant neoplasms for different time periods from 1943 to 2000. Risks of second malignant neoplasms were assessed through standardized incidence ratios (SIRs) and corresponding 95% confidence intervals (CIs), using the incidence rates in the general populations covered by the registries as a reference. Cumulative absolute risks were also calculated.


RESULTS
A total of 133 second malignant neoplasms were observed in 16,540 patients (12,731 leukemias, 1246 Hodgkin lymphomas, and 2563 non-Hodgkin lymphomas) after an average follow-up of 6.5 years. The most frequent second malignancies after leukemia were brain cancer (19 cases, SIR = 8.52, 95% CI = 5.13 to 13.3), non-Hodgkin lymphoma (nine cases, SIR = 9.41, 95% CI = 4.30 to 17.9), and thyroid cancer (nine cases, SIR = 18.8, 95% CI = 8.60 to 35.7); the most frequent after Hodgkin lymphoma were thyroid cancer (nine cases, SIR = 52.5, 95% CI = 24.0 to 99.6), breast cancer (six cases, SIR = 20.9, 95% CI = 7.66 to 45.4), and neoplasms of skin (non-melanoma) (six cases, SIR = 34.0, 95% CI = 12.5 to 74.0); and the most frequent after non-Hodgkin lymphoma were thyroid cancer (six cases, SIR = 40.4, 95% CI = 14.8 to 88.0) and brain cancer (four cases, SIR = 6.97, 95% CI = 1.90 to 17.9). Cumulative incidence of any second malignant neoplasm was 2.43% (95% CI = 1.09 to 3.78), 12.7% (95% CI = 8.29 to 17.2), and 2.50% (95% CI = 1.04 to 3.96) within 30 years from diagnosis of leukemia, Hodgkin lymphoma, and non-Hodgkin lymphoma, respectively.


CONCLUSIONS
This population-based study provides, to our knowledge, the most precise and up-to-date estimates for relative and absolute risks of second malignant neoplasms after childhood leukemia and lymphoma.
Maule
Milena
M
Childhood Cancer Registry of Piedmont, Cancer Epidemiology Unit, CPO Piemonte, CeRMS, University of Turin, Via Santena 7, 10126, Turin, Italy. milena.maule@unito.it
Scélo
Ghislaine
G
Pastore
Guido
G
Brennan
Paul
P
Hemminki
Kari
K
Tracey
Elizabeth
E
Sankila
Risto
R
Weiderpass
Elisabete
E
Olsen
Jorgen H
JH
McBride
Mary L
ML
Brewster
David H
DH
Pompe-Kirn
Vera
V
Kliewer
Erich V
EV
Chia
Kee Seng
KS
Tonita
Jon M
JM
Martos
Carmen
C
Jonasson
Jon G
JG
Merletti
Franco
F
Boffetta
Paolo
P
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007938:Leukemia / Q000473:pathology*; D008223:Lymphoma / Q000473:pathology*; D008297:Male; D016609:Neoplasms, Second Primary / Q000453:epidemiology*; D012042:Registries; D012307:Risk Factors; D017741:Survivors / Q000706:statistics & numerical data*