## 4 Discussion  
Surgical treatment is often curative for localized PC and preoperative staging is essential to refine decision-making strategy. Based on contemporary literature, pelvic MRI appears to be a promising imaging tool to assess tumor size and local extension [19]. In consequence, our aim was to systematically review the role of MRI as a reliable and accurate imaging modality for preoperative local staging of primary PC. Our analyses led to several noteworthy findings. First, diagnostic performance of MRI in detecting TA invasion showed an accuracy of 0.89 with a sensitivity of 0.78, a PPV of 0.79, a specificity of 0.91, and an NPV of 0.90. In consequence, MRI may represent a reliable tool to exclude TA invasion. This result is mainly imputable to the study from [PERSON] et al. [13], which relied on the greatest sample size (\(n\) = 200) and reported an interesting high specificity of 0.99 (95% CI: 0.95-1.00). Second, diagnostic performance of MRI in detecting urethral invasion showed an accuracy of 0.88 with a sensitivity of 0.65, a PPV of 0.46, a specificity of 0.86, and an NPV of 0.93. In consequence, MRI may represent a reliable tool to exclude urethral invasion. Here, the study from [PERSON] et al. [15] was the most informative (\(n\) = 100) and reported an interesting high NPV of 0.92 in urethral invasion. Third, we tested the diagnostic performance of MRI in detecting pT \(\geq\) 2. This endpoint was calculated basing on extractable data from eligible studies (four out of six), as reported in Section 2.4. We observed a diagnostic accuracy of 0.90 with a sensitivity of 0.86, a PPV of 0.84, a specificity of 0.70, and an NPV of 0.73. These results showed that MRI accurately identifies patients with local extension beyond subepithelial connective tissue. Taken together, our analyses supported the role of MRI in preoperative staging of localized PC. Specifically, MRI adequately performs in excluding TA and urethral invasion, as well as in detecting extension beyond subepithelial connective tissue. These observations are of utmost importance in preoperative patient counselling, when planning organ-sparing surgery in primary PC. As stated by EAU guidelines, in patients with invasion of both  
Figure 4: Pooled sensitivity, specificity, and SROC curve of MRI in pathologic T-stage \(\geq\) 2.  
corpus cavernosum and urethra, partial or total pencectomy with perineal urethrostomy is strongly recommended, since these patients yield an increased risk of local recurrence (35%) and a 5-year mortality of 30% [20]. In consequence, the ability of MRI to exclude both TA and urethral invasion may allow clinicians to refine surgical management [21]. Despite our encouraging findings, one could argue that MRI is an expensive technique. However, over the last decade, MRI has been increasingly adopted in preoperative staging of genito-urinary cancers and is currently widely available in most centers [22; 23]. Nonetheless, the use of this imaging modality is still limited by relative or absolute contraindications such as cardiac implantable electronic device, metallic intraocular foreign bodies, implantable neurostimulation systems, coronary and peripheral artery stents, inferior vena cava filters, and penile protheses [24]. To best of our knowledge, we are the first to systematically review and meta-analyze the literature addressing the diagnostic performance of MRI in preoperative local staging of PC patients. In consequence, our results cannot be directly compared to others. However, our study is not devoid of limitations. First, only seven studies were identified and three of them were retrospective. Nonetheless, it is not negligible that PC is a relatively rare condition. Second, there was heterogeneity in the MRI magnetic field strength among eligible studies. This could lead to biased interpretation of T1- and T2-weighted sequences, which are the most useful in determining local extent of penile cancer. Moreover, only three studies relied on more than one reader to interpret images [12; 14; 15].