AB121. The prognostic impact of squamous and glandular differentiation for upper tract urothelial carcinoma patients after radical nephroureterectomy

OBJECTIVE: To evaluate the association between tumor squamous and/or glandular differentiation and tumor biological characteristics, to validate the impact of these histologic variants on oncologic outcomes of UTUC patients. METHODS: We retrospectively analyzed the data of 687 UTUC patients who underwent radical nephroureterectomy in our institute, from Aug 1, 1999 to Dec 31, 2011. All pathologic sections were reevaluated for histologic differentiation variations (squamous and glandular). The clinicopathological variables of patients were reviewed. RESULTS: Among the 687 UTUC patients in our study, 53 (7.7%) had squamous differentiation, 20 (2.9%) had glandular differentiation and 8 (1.2%) had both histologic variants. Patients with mixed histologic variant tended to have significant larger percentage of sessile tumor architecture (58.0% vs. 18.2%), presence of CIS (7.4% vs. 2.3%), advanced T stage, advanced tumor grade and lymph node metastasis (17.3% vs. 6.6%) (all P<0.05). Median follow-up duration was 65 months (range 3 to 144). The 5-year cancer specific survival was 72.0% for patient with pure UTUC, and 48.9% for patients with histologic variants (P<0.001). Patients with both squamous and glandular differentiations did not show significantly worse CSS than those with single histologic variant. Univariate analyses revealed that tumor squamous and/or glandular differentiation were significant factors on survival (P<0.001). However, the influence did not remain significant after adjusted for other factors in the multivariate analyses (P=0.076, HR =1.42). CONCLUSIONS: UTUC patients with squamous and/or glandular differentiation are more likely to have aggressive tumor biological features, and tend to have worse postoperative outcomes.