Radiotherapy of testicular intraepithelial neoplasia (TIN): a novel treatment regimen for a rare disease.
OBJECTIVE
Testicular intraepithelial neoplasia (TIN) is a consistent precursor of most invasive germ cell tumors, currently treated by radiotherapy with 20 Gy, which destroys TIN but preserves Leydig cells. Nevertheless, analysis has shown dose-dependent dysfunction even with low therapeutic doses of 20 Gy in some cases. Therefore, we tested a dose reduction regimen by delivering smaller fractional doses to enhance the tolerance of Leydig cells.


METHODS
Between 1993 and 1999, 9 patients were treated for TIN in a prospective multicenter trial. A total dose of 13 Gy was administered in 10 fractions of 1.3 Gy. Hormonal levels of follicle-stimulating hormone, luteinizing hormone, and testosterone were assayed serially.


RESULTS
During a median follow-up time of 36 months, no patient showed evidence of local disease. A first postradiation biopsy was obtained 3-12 months after radiotherapy; 5 patients underwent a second biopsy 2-3 years after treatment. All biopsies showed a Sertoli cell-only pattern. Follicle-stimulating hormone levels continued to increase 1 year after radiotherapy, signaling eradicated spermiogenesis. Luteinizing hormone and testosterone remained within the normal range 2 years after radiotherapy.


CONCLUSIONS
In the treatment of TIN, there seems to be a dose reduction potential to 13 Gy by lowering single fractional doses, which enhances the therapeutic ratio in favor of the Leydig cells.
Sedlmayer
F
F
Department of Radiotherapy and Radio-Oncology, Landeskliniken Salzburg, Salzburg, Austria. F.Sedlamyer@lks.at
Höltl
W
W
Kozak
W
W
Hawliczek
R
R
Gebhart
F
F
Gerber
E
E
Joos
H
H
Albrecht
W
W
Pummer
K
K
Kogelnik
H D
HD
D000328:Adult; D015415:Biomarkers / Q000097:blood; D002278:Carcinoma in Situ / Q000097:blood / Q000532:radiotherapy*; D019583:Dose Fractionation, Radiation; D005640:Follicle Stimulating Hormone / Q000097:blood; D005500:Follow-Up Studies; D006801:Humans; D007985:Leydig Cells / Q000528:radiation effects; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D011836:Radiation Tolerance; D013093:Spermatogonia / Q000528:radiation effects; D013736:Testicular Neoplasms / Q000097:blood / Q000532:radiotherapy*; D013739:Testosterone / Q000097:blood
D015415:Biomarkers; D013739:Testosterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone