Renal cancer and pregnancy in two different female cohorts

Although human renal cell carcinoma (RCC) is considered refractive to hormone therapy, this lesion can be induced in the Syrian hamster by exogenous estrogen. Human RCC also has been demonstrated to contain estrogen receptors. Since there are significant changes of estrogen levels during pregnancy, we wanted to investigate if there were any associations between the hormonal variations of pregnancy and renal cancer in women using two distinct cohorts.

We reviewed the charts of 57 females who presented for treatment of renal cancer. We assessed the size of each tumor radiologically and pathologically, the tumor stage, the number of pregnancies and/or abortions/miscarriages, age at menarche, and use of oral contraceptives. We compared this cohort to a sample of 985 nuns, and then reviewed the literature on the association of pregnancy, contraceptives and renal cell carcinoma. We used analysis of multiple variables (ANOVA) and the student's t test to determine any significance (p<0.05).

Our age range was 39 to 67 years, with a mean of 51. The tumor volumes ranged from 9 cm(3) to 1500 cm(3), and the number of pregnancies ranged from 1 to 14. Menarche ranged from 8 to 14. We did not find any significant correlation between menarche or the number of pregnancies and the size or stage of renal cancers. However, our nun population did not reveal any incidence or illness from renal cell carcinoma over a 20 year review.

Although our first cohort did not demonstrate any significant associations between the number of pregnancies or age at menarche and RCC, our second cohort and a review of the literature supports the notion that pregnancy is a risk factor for renal cell carcinoma.