This was a retrospective multicenter analysis of 1,610 patients treated with RNU for clinically non-metastatic UTUC between 1990 and 2016. Lymph node dissection was not standardized, and surgeons performed it at their discretion. The histological variants that were analyzed included micropapillary, squamous, sarcomatoid and others (less than 10 cases for each). Multivariable competing risk analyses was finally performed to assess the effect of variant histology on overall recurrence and cancer-specific mortality.
Overall, 1,460 (91%) had pure urothelial carcinoma whereas 150 (9%) patients were diagnosed with variant histology. Of the variant histology patients, 89 (5.0%) had micropapillary variant, 41 (2.0%) had squamous, 10 (1.0%) had sarcomatoid and 10 (1.0%) had others. Multivariable competing risk analysis (figure 1) demonstrated that the micropapillary variant histology was the only variant associated with an increased rate of recurrence (HR 2.49, 95% CI 1.29-4.82, p=0.006). However, the sarcomatoid variant was the only variant associated with increased cancer-specific mortality (HR 20.63, 95% CI: 9.39-45.31, p < 0.001).
In conclusion, a tenth of the patients with UTUC treated with RNU manifest variant histology. On multivariable analysis, after adjusting for known confounders, micropapillary and sarcomatoid variants were shown to be associated with increased recurrence rate and cancer-specific mortality, respectively.
Figure 1 – Multivariable analysis for recurrence and cancer specific mortality:
Presented by: Stefania Zamboni, MD, Urology Operations Unit, Brescia, Italy
Written By: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre @GoldbergHanan at the American Urological Association's 2019 Annual Meeting (AUA 2019), May 3 – 6, 2019 in Chicago, Illinois