Maternal and birth characteristics and childhood rhabdomyosarcoma: a report from the Children's Oncology Group.
OBJECTIVE
Previous assessments of childhood rhabdomyosarcoma have indicated maternal and birth characteristics may be associated with tumor development; however, much work remains to identify novel and confirm suspected risk factors. Our objective was to evaluate the associations between maternal and birth characteristics and childhood rhabdomyosarcoma.


METHODS
This case-control study included 322 cases and 322 pair-matched controls. Cases were enrolled in a trial run by the Intergroup Rhabdomyosarcoma Study Group. Population-based controls were identified using random digit dialing and were individually matched to cases on race, sex, and age. Families of the case and control subjects participated in a telephone interview, which captured information on maternal characteristics (birth control use, number of prenatal visits, anemia, and abnormal bleeding during pregnancy) and birth characteristics [birth weight, preterm birth, and type of delivery (vaginal vs. cesarean)]. Conditional logistic regression models were used to calculate an odds ratio (OR) and 95% confidence interval (CI) for each exposure, adjusted for age, race, sex, household income, and parental education. As the two most common histologic types of rhabdomyosarcoma are embryonal (n = 215) and alveolar (n = 66), we evaluated effect heterogeneity of these exposures.


RESULTS
The only characteristic that was associated with childhood rhabdomyosarcoma, and statistically significant, was abnormal vaginal bleeding during pregnancy (OR 1.75, 95% CI 1.12-2.74). Birth control use (OR 1.45, 95% CI 0.96-2.18), anemia during pregnancy (OR 1.27, 95% CI 0.81-1.99), and preterm birth (OR 2.51, 95% CI 0.74-8.49) were positively associated with childhood rhabdomyosarcoma, but were not statistically significant. Low birth weight [adjusted odds ratios (aOR) 4.46, 95% CI 1.41-14.1] and high birth weight (aOR 2.41, 95% CI 1.09-5.35) were strongly associated with alveolar rhabdomyosarcoma. However, these factors did not display significant effect heterogeneity between histologic types (p > 0.15 for all characteristics).


CONCLUSIONS
Overall, we found little evidence that these maternal and birth characteristics are strongly associated with childhood rhabdomyosarcoma.
Department of Pediatrics, Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, USA, philip.lupo@bcm.edu.
Philip J
PJ
Lupo
Heather E
HE
Danysh
Stephen X
SX
Skapek
Douglas S
DS
Hawkins
Logan G
LG
Spector
Renke
R
Zhou
M Fatih
MF
Okcu
Karin
K
Papworth
Erik B
EB
Erhardt
Seymour
S
Grufferman
D001722:Birth Order; D001724:Birth Weight; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008423:Maternal Age; D016017:Odds Ratio; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology; D012208:Rhabdomyosarcoma / Q000453:epidemiology*; D012307:Risk Factors