Gonadal effects of irradiation-Males

The testes are directly irradiated in the treatment of leukaemic relapse, tumours of the

lower pelvis and carcinoma in situ (CIS) of the testis. The germinal epithelium is highly sensitive

to irradiation and unlike most tissues is not spared by fractionation. The threshold dose for

effect is low, and with increasing dose there is a rapid increase in damage. The degree of risk will

be dose- and technique-dependent.

Transient suppression with subsequent recovery of spermatogenesis occurs with doses as

low as 0.5 Gy. Following 2–3 Gy there is a period of azoospermia after which full recovery is

expected within three years; at doses of 4–6 Gy recovery is not universal and may take up to five years; after 6 Gy there is a high risk of permanent sterility. Total body irradiation (TBI) with high-dose chemotherapy will sterilise men.

The Leydig cell is more resistant to irradiation. Nevertheless, a dose of irradiation in excess

of 15 Gy may be sufficient to affect Leydig cell function and production of testosterone, and a

dose of 24 Gy will irreversibly damage the Leydig cells in prepubertal boys.

When directly in the irradiation field the testes cannot be protected. The dose from

scattered irradiation from nearby beams can, however, be reduced by moving the gonad away

from the beam and, in some circumstances, by applying thick shielding cups directly over the

scrotum. Displacement of the scrotum away from lateral pelvic and proximal thigh fields with

taping during radiotherapy may be the most effective means available.

The beneficial effect of specific testicular shielding in reducing the dose from scattered

irradiation has been debated and depends on the position and nature of the radiation field.

Irradiation to the pelvic lymph node areas, as in the treatment of testicular tumours or lymphoma, results in a scattered dose to the testis of 1.5–3 Gy. In this situation, testicular shielding may be used and the dose reduced to the order of 0.5–0.8 Gy.11,12 Shielding placed directly on and around the scrotum is required and needs to be of a thickness to reduce an incident dose to 5% or less. The practical difficulties of this are considerable and the shield may impede the more effective measure of displacing the scrotum away from the beam, as described above.

courtesy-treatment on reproductive functions,Guidance on management

Report of a Working Party,November 2007.