Gonadal dose considerations for Japanese children

Infertility thresholds are lower than i thought

There is a study available from the International Journal of Radiation Oncology * Biology * Physics, which attempted "to estimate the doses of radiation to organs of interest during treatment of childhood cancer for use in an epidemiologic study of possible heritable diseases, including birth defects, chromosomal abnormalities, cancer, stillbirth, and neonatal and premature death". Interesting data.

Results

Testicular radiation doses ranged from <1 to 700 cGy (median, 7 cGy) and ovarian doses from <1 to >2,500 cGy (median, 13 cGy). Ten percent of the records were incomplete, but sufficient data were available for broad characterizations of gonadal dose. More than 49% of the gonadal doses were >10 cGy and 16% were >100 cGy.

Conclusions

Sufficient radiation therapy data exist as far back as 1943 to enable computation of gonadal doses administered for curative therapy for childhood cancer. The range of gonadal doses is broad, and for many cancer survivors, is high and just below the threshold for infertility. Accordingly, the epidemiologic study has >90% power to detect a 1.3-fold risk of an adverse pregnancy outcome associated with radiation exposure to the gonads. This study should provide important information on the genetic consequences of radiation exposure to humans.

84% of the doses were under 100 centigray (1 Sievert) cumulative, with an average dose of just 70 millisieverts. With thyroid concerns getting most of the attention, it's easy to forget about the long term effects of other areas of the body.