<p><strong> </strong><strong>If a bladder-sparing approach is being considered in patients with subtype histology, clinicians should perform a restaging TURBT within four to six weeks of the initial TURBT. (<em>Expert Opinion</em>)</strong></p>
Discussion
Discussion
<p>Historically, subtype histologies have been under-appreciated and under-reported, but data is accumulating in regards to their aggressiveness. With their higher potential oncologic risk, the Panel believes that if a clinician is considering any treatment that would preserve the bladder, that at a minimum, a repeat TURBT should be done to evaluate clinical stage for these tumor types.</p>
<p>The presence of subtype histology within the TURBT specimen is uniformly associated with high-grade disease and almost always invasive. In one study, 86% of patients with subtype histology presented with muscle-invasive disease at TURBT compared to 53% of those with high-grade pure urothelial carcinoma. At cystectomy, 64% of the patients with subtype histology were found to have T3-T4 disease compared to 34% of those with pure high-grade urothelial carcinoma.<sup>99</sup> In 2021, Iida et al. reported on a cohort of 94 patients with BCG-unresponsive NMIBC treated without radical cystectomy. They found that the presence of subtype histology was an independent predictor of poor overall survival. Although this study did not evaluate the role of repeat TURBT in this population, it does support the high-risk nature of subtype histology.<sup>100</sup> As such, patients with subtype histologic features are generally not ideal candidates for bladder-preserving protocols and are best served with an aggressive treatment modality.<sup>101</sup> In further support, additional studies have demonstrated a similar more aggressive nature of these subtypes in muscle-invasive disease.<sup>102, 103</sup></p>