Introduction:
Testicular cancer (TC) is the most common form of germ-cell tumor (GCT) in the general population and the most common type of cancer among young men in Europe. Despite this knowledge, there have been no studies on TC in kidney transplant recipients (KTRs) apart from individual case reports. This is the first population study on KTRs with TC, and we conducted it to share our experience and provide insight into the characteristics and outcomes of TC in KTRs.
Methods:
We conducted a multicenter, multinational, cross-sectional study across 9 transplant centers in Croatia, Serbia, Montenegro, Slovenia, and Bosnia and Herzegovina. The study included all KTRs aged 18 and above. Data was collected from electronic medical records at the transplant centers and compiled using a Microsoft Excel spreadsheet.
Results:
Among the 3500 KTRs on regular check-ups in 9 transplant centers that participated in our study, 6 (0.17%) developed TC after kidney transplantation (KT). The median age of the KTRs at TC diagnosis was 41 years. The median post-transplant time at the TC diagnosis was 5 years. Four KTRs had a positive family history of cancer in first-degree relatives. Induction therapy was basiliximab in half of the KTRs; 1 KTR received anti-thymocyte globulin, and 1 KTR received cyclosporine. Five KTRs received maintenance immunosuppression (IS) therapy of tacrolimus, mycophenolate, and prednisone. One KTR who underwent KT in 1986 received no induction therapy; his maintenance IS consisted of cyclosporine and azathioprine and was not modified after the stage 1 seminoma diagnosis 12 years after the KT. He was successfully treated with orchiectomy and had a functional kidney allograft for another 9 years. Another 2 KTRs had stage 1 seminoma, 1 had embryonal carcinoma, and 1 had mixed GCT composed of seminoma, embryonal carcinoma, yolk sac tumor, teratoma, and choriocarcinoma. All but one were treated with orchiectomy and switched from tacrolimus to mTOR inhibitor (mTORi). The only KTR who was not treated with orchiectomy of the remaining testicle was the one who underwent unilateral orchiectomy due to testicular teratoma before KT. He was diagnosed with seminoma with retroperitoneal nodal metastasis 19 months after the KT complicated with regional deep vein thrombosis. He was treated with chemotherapy and anticoagulant therapy and switched to mTORi. Remission was achieved, but he required chronic dialysis 8 years after the TC diagnosis and died from COVID-19. None of the KTRs had relapses, secondary tumors, or acute rejections due to IS modification and cancer therapy.
Conclusions:
Even though TC is the most common solid tumor in men aged 15 to 45, it is the 27th most common cancer globally in the general population, which makes it a rare tumor type. Our analysis showed that it is also rare in KT population. We also showed that patients diagnosed with stage 1 TC, treated with orchiectomy and IS modification, have good prognoses. The only patient with a poor outcome was the one with a history of testicular teratoma before KT, who was not treated with orchiectomy of the remaining testicle after the diagnosis of metastatic seminoma after the KT. However, considering this is the first population study on TC in KTRs, further studies are needed to evaluate its frequency, risk factors, management, and prognosis in this particular patient population.
I have no potential conflict of interest to disclose.
I did not use generative AI and AI-assisted technologies in the writing process.