EFFECT OF LOW-DOSE TESTICULAR IRRADIATION ON SPERM COUNT AND FERTILITY IN PATIENTS WITH TESTICULAR SEMINOMA

The treatment of seminoma with radiation therapy risks transient infer tility. We have prospectively followed eight patients with stage I sem inoma of the testicle. All patients underwent radical orchiectomy of t he affected testis. The mean age of the patients was 32.9 years (range 24-40). Each patient was treated with megavoltage radiation with a 10 - or 18-MV linear accelerator. The remaining testicle was shielded usi ng a standard lead enclosure, and the mean testicular dose was 44 cGy (range 20.8-78.2). Semen specimens were delivered to the lab within 30 minutes of ejaculation. All specimens were analyzed using a computer- assisted sperm analyzer. Pretreatment parameters were within normal li mits for all but one patient; one patient presented with a borderline normal sperm count at 18 and 22 x 10(6)/ml. Following treatment, there was a decrease in sperm count, detected at 3 months, to <10 x 10(6)/m l (range 4.4-8.6 x 10(6)) in all patients except one, who presented wi th an initial pretreatment count of 189 x 10(6)/ml, which decreased to 58 x 10(6)/ml at 3 months, 32 x 10(6)/ml at 6 months, and rose to 325 x 10(6)/ml by 12 months following treatment. Although the sperm count for this patient (D.L.) was within the normal range, the post-radiati on sperm count was less than 20% of the pretreatment count. There was no difference in the motility at 3 months, the mean of which was 51.3% . One patient's (F.C.) wife conceived at 9 months following treatment, one at 12 months (J.R.), and one (J.S.) at 14 months, and all have de livered normal infants. Of the remaining patients, four patients recov ered sperm counts within the normal range by 1 year (range 38-325 x 10 (6)/ml), one by 18 months, and one by 30 months. Of the two remaining patients, one did not return for sperm analysis after the couple had a child using banked sperm, and the second was able to conceive a child at 14 months and believed that a sperm count was superfluous. The ear liest recovery was seen at 12 months. In the present study, recovery w as seen at doses of less than or equal to 65 cGy, although the one pat ient receiving a dose of 90 cGy conceived naturally and did not return for follow-up sperm analysis after a sperm count at 12 months (4.3 x 10(6)/ml). There is thus a transient decrease in sperm count following megavoltage radiation treatment with testicular doses between 28 and 90 cGy, with recovery of normal sperm count or the ability to father o ffspring by a maximum of 30 months after treatment. A study of serial semen analyses in patients with Hodgkin's disease (and two patients wi th testicular seminoma) from this institution was updated to serve as a comparison for this study.