Introduction: We aimed to perform a systematic review on the effects of testis-sparing surgery (TSS) on the oncological, functional, and hormonal outcomes of adults with testicular tumors.

Methods: A literature search was performed after PROSPERO registration (CRD42020200842) and reported in compliance with PRISMA methods. We conducted a systematic search of Medline (Ovid), Embase, Cochrane CENTRAL, CINAHL, Scopus, Web of Science, ClinicalTrials.gov, and the WHO/ICTRP from inception to November 20, 2020. Manuscripts and published abstracts were included if they involved TSS and reported on at least one of the outcome measures. Case reports were excluded.

Results: Our initial search yielded 3370 manuscripts, with 269 of these screened for full-text eligibility. A total of 32 studies were included in the final analysis. Oncological outcomes were obtained from 12 studies, functional data from 26, fertility information from 10, and data on non-palpable tumors from 11 studies. Oncological control appears to be excellent in studies that reported these outcomes. Presence of germ cell neoplasia in situ was controlled with adjuvant radiation in nearly all cases. Functional outcomes are also promising, as development of primary and compensated hypogonadism was rare. Semen parameters are poor preoperatively among men with benign and malignant testis tumors, with occasional decline after TSS. Frozen section analysis at the time of surgery appears to be very reliable, and the majority of non-palpable tumors appear to be benign.

Conclusions: TSS is a safe and efficacious technique with regards to oncological control and postoperative hormonal function based on retrospective, non-controlled studies. TSS avoids unnecessary removal of benign testicular tissue and should be given serious consideration in cases of non-palpable, small tumors under 2 cm. In cases of malignancy, TSS can safely avoid anorchia in men with bilateral tumors and in men with solitary testicles.