Ewing's sarcoma family of tumours (ESFT) represents a group of rare neoplasms that includes Ewing's sarcoma of the bone and soft tissue and peripheral primitive neuroectodermal tumours of the bone and soft tissue. There are only a few reasonably detailed aetiological studies of Ewing's sarcoma of the bone in the literature. While several associations were suggested, particularly paternal occupation on farming, results were not consistent across the studies and analysis relied on relatively small sample sizes.
Materials and Methods
Cases of ESFT diagnosed in Australia between January, 1991 and June, 1996 who were under 40 years at diagnosis were compared with a population based control subjects frequency matched to cases date of birth and State of residency. Out of 155 cases ascertained, 132 were included in the study. The sampling frame for control
selection consisted of all telephone numbers listed in an electronic directory. Out of 473 controls invited to participate, 428 families (90.5%) were interviewed. A face-to-face (83.9%) and telephone interview using a structured questionnaire were used to collect the data.
Amongst selected demographic characteristics studied, mother's education beyond completion of high school (used as proxy for socioeconomic status) (ORadj = 1.63, 95% CI 1.08 - 2.47) and male sex (ORadj = 1.86, 95% C11.23 - 2.83) were, in this study, positively associated with ESFT. Within age groups male and female cases were usually taller than controls, males aged 11 to 14 averaged 161.0 cm (±3.7) and controls were 152.7 cm (±1.5) tall (p-value = 0.037). Pubertal history was similar for females, male cases shaved earlier than their counterparts. Subjects were 4 times more likely to
develop ESFT if they were "much more active" compared to "much less active". There was an inverse association between risk of ESFT and amount of sun exposure and having been sunburnt.
Overall, there were a few positive associations between subjects medical history and ESFT, the only occurring notably more frequently in cases was hernia (ORadj =2.97, 95% C11.42 - 6.21). Regarding pregnancy and neonatal related risk factors few positive associations were found. Cases were on average 130 grams (p-value = 0.028) heavier and 1 cm (p-value = 0.047) longer at birth than controls, more case mothers took antibiotics (ORadj =1 -49, 95% CI 0.68 - 3.18) or had x-rays during pregnancy (ORadj = 1.73, 95 % CI 0.69 - 4.34). There was an increased risk of ESFT for those whose mothers worked in farms during pregnancy (ORadj = 1.67, 95% CI 0.34 - 8.33)
and for those whose mother usual occupation was classified as "blue collar workers" (ORadj = 1.46, 95% CI 0.81 -2.63). Father's occupation was not positively associated with ESFT in the offspring. Farm residency was associated with an increased risk of ESFT (ORadj =1.51, 95 % CI 0.93 - 2.43), and subject's exposure to cattle or sheep dip was also a risk factor for the younger cases (particularly those 0-10 year olds).
Results from this study gave only modest support to the hypothesis of an association between farm residency and ESFT, and did not support previous findings regarding paternal occupation on farming. Despite detecting a few other potential risk factors a lot more has to be understood before one can come up with the final model of causation for ESFT.