443 IMPACT OF HISTOLOGY ON CANCER CONTROL AFTER NEPHRON SPARING SURGERY FOR RENAL CELL CARCINOMA

441



442

Techniques, safety and accuracy of needle biopsy of renal tumours: review of the Toronto UHN experience

Renal Cell Carcinoma with Rhabdoid Features: An Aggressive Neoplasm with overexpression of p53

Volpe A.1, Kachura J.2, Evans A.3, Geddie W.3, Gharajeh A.4, Saravanan A.3, Jewett M.4

Zini L.1, Leroy X.2, Aubert S.2, Ballereau C.1, Fantoni J.C.1, Lemaitre L.3, Biserte J.1, Villers A.1

San Luigi Gonzaga Hospital, University of Torino, Department of Urology, Torino, Italy, Princess Margaret Hospital and the University Health Network, Department of Medical Imaging, Toronto, Canada, 3Princess Margaret Hospital and the University Health Network, Department of Pathology, Toronto, Canada, 4Princess Margaret Hospital and the University Health Network, Division of Urology, Department of Surgical Oncology, Toronto, Canada 1 2

Introduction & Objectives: The majority of renal tumors are today incidentally detected as small renal masses on imaging. Many surgically removed small masses are benign tumours or low grade renal cell carcinomas (RCC). There is increasing evidence that in selected patients small renal tumours can be safely managed with an initial period of active surveillance and delayed intervention for those that progress with a rapid growth rate. Percutaneous biopsy of renal tumours for pathological diagnosis and to aid treatment decision making has not been widely used because of concerns about tumor implantation and sampling errors. The potential presence of intratumoral heterogeneity has been considered a significant issue, because it may interfere with an accurate histological diagnosis. We reviewed our experience with percutaneous needle core biopsy of renal masses to assess safety and diagnostic accuracy. Material & Methods: 65 needle core biopsies of renal masses were performed at the University Health Network in Toronto since January 2001. The biopsies were performed under ultrasound and/or CT guidance. An 18-gauge side-cutting needle was used to obtain the cores. A retrospective chart review was performed to document the complication rate and the ability to obtain sufficient tissue for diagnosis. To assess the presence of intratumoral heterogeneity in small tumors we reviewed the slides of 43 surgically removed <3 cm RCC’s. Results: 6 of 65 biopsies (9.2%) produced minor bleeding that was easily controlled with the placement of gelfoam pledgets through the biopsy coaxial sheath. No other significant complications and no cases of tumor seeding were reported. 57 of 65 biopsies (87.7%) were diagnostic. 20 patients underwent a radical or partial nephrectomy after a diagnostic needle biopsy. In all these cases pathology on the biopsy and on the surgical specimen were concordant. One renal mass was removed after a non diagnostic biopsy and was found to be a papillary RCC. 7/43 (16%) small tumors that were reviewed displayed intratumoral heterogeneity. Conclusions: In our experience percutaneous needle core biopsy of renal masses is a safe and accurate diagnostic procedure. Needle biopsies are likely to provide tissue samples that are representative of the entire tumour in the majority of the cases. Percutaneous biopsy should have an increasing role in the diagnostic management of renal masses and can have a significant impact in treatment decision making, especially in elderly and unfit patients.



443

1 3

CHRU Lille, Urology, Lille, France, 2CHRU Lille, Pathology, Lille, France, CHRU Lille, Radiology, Lille, France

Introduction & Objectives: Adult renal cell carcinoma (RCC) with rhabdoid features is a recently recognized morphologic variant of kidney carcinoma. To date, only very few studies have been published on this subject and p53 was not previously studied. To evaluate clinical attributes, morphology, and immunohistochemistry in RCC with rhabdoid component. Material & Methods: Reviewing a consecutive series of 310 RCCs, we identified 14 cases of RCC with rhabdoid features. All cases were reviewed and subjected to detailed clinical and pathologic studies with immunohistochemical evaluation of p53. Results: All tumors were clear RCCs with rhabdoid component representing from 5% to 50% of the tumor volume. Rhabdoid cells were large with a central eosinophilic intracytoplasmic inclusion and an eccentric atypical nucleus. Tumor necrosis was common (13 of 14) and sometimes extensive. Nine of 14 tumors were staged pT3, 4 of 14 were staged pT2, and only 1 tumor was pT1. On immunohistochemistry, rhabdoid cells were positive for vimentin (14 of 14), epithelial membrane antigen (11 of 14), and cytokeratin (9 of 14). Desmin and smooth muscle actin were always negative. p53 was positive in 10 of 14 tumors in the rhabdoid areas (5% to 50% of tumor cells stained) but only in 5 of 14 cases in usual clear renal cell areas. In the follow-up, 10 of 14 patients developed metastases and 6 of 14 died of the disease. The median of survival was 8 months. Conclusions: We showed that RCC with rhabdoid features is a very aggressive neoplasm with a poor prognosis. We observed an overexpression of p53 in the rhabdoid component that may be implicated in the tumor dedifferentiation.



444

Impact of histology on cancer control after nephron sparing surgery for renal cell carcinoma

Prognostic significance of macroscopic tumor necrosis in renal cell carcinoma

Crepel M.1, Verhoest G.1, Bernhard J.C.2, Ferriere J.M.2, Bellec L.3, Soulie M.3, Albouy B.4, Pfister C.4, Lopes D.5, De La Taille A.5, Salomon L.5, Abbou C.5, Tostain J.6, Guille F.1, Vincendeau S.1, Manunta A.1, Colombel M.7, Belldegrun A.8, Pantuck A.J.8, Patard J.J.1

Lee S.E.1, Yu J.H.1, Han B.K.1, Han J.H.1, Jeong S.J.2, Byun S.S.1, Choe G.3, Choi H.4, Hong S.K.1

Rennes University Hospital, Urology, Rennes, France, 2Bordeaux University Hospital, Urology, Bordeaux, France, 3Toulouse University Hospital, Urology, Toulouse, France, 4Rouen University Hospital, Urology, Rouen, France, 5Henri Mondor University Hospital, Urology, Creteil, France, 6 Saint Etienne University Hospital, Urology, Saint Etienne, France, 7Lyon University Hospital, Urology, Lyon, France, 8UCLA, Urology, Los Angeles, United States of America

Introduction & Objectives: Recently, the pathologic feature of tumor necrosis has been gaining attention as being a prognostic factor for renal cell carcinoma (RCC). Meanwhile, in cases where the extent of necrosis is small, the results of microscopic analysis for tumor necrosis would be more affected by the way sections of specimen are made. Thus, we tried to investigate the prognostic significance of macroscopic tumor necrosis regarding RCC.

1

Introduction & Objectives: To evaluate whether or not histologic subtype has an impact on cancer control after nephron sparing surgery in Renal Cell Carcinoma (RCC) Material & Methods: Patients from 8 international academic centers who underwent a partial nephrectomy for RCC were included in this study. Histologic subtype (clear cell vs papillary vs chromphobe), age, sex, tumor size, TNM stage, Fuhrman grade, information on multifocality, recurrence rate and cancer specific survival were recorded in all cases. Qualitative and quantitative variables were compared by using Chi-square (Fischer exact test) and Student t tests, respectively. Results: 807 patients were included in this retrospective study. There were 574 men (71.1%) and 233 women (28.9%). Median tumor size was 3 cm (0.5-17). Tumors were classified as Stage T1, T2, T3 in 715(89%), 26(3.2%) and 63(7.8%) cases, respectively. Clear cell, papillary and chromophobe carcinomas accounted for 590(73.1%), 168(20.8%) and 49(6.1%) of the cases respectively. Overall, 23 patients (2.9%) experienced a local recurrence and 36(4.5%) died from cancer. Mean tumor size was not significantly different between the 3 histologic groups (3.3 vs 3.3 vs 3.6 cm). Multifocality was not found to be significantly increased in papillary tumors (86(14.7%) vs 21(12.7%) vs 2(4.1%)). Local recurrence rate was not influenced by tumor histology: 19 patients with clear cell tumors recurred (3.4%) compared to 3 patients with papillary tumors (1.9%) and 1 patient (2.1%) with chromophobe carcinoma (p:0.6). Similarly, the risk of cancer related death was independent from histologic subtype: 30 (5.6%) patients with clear cell histology died from cancer compared to 5(3.2%) and 1(2.2%) in papillary and chromophobe carcinomas respectively (p:0.3). Conclusions: Due to their smaller size and generally better outcome compared to clear cell histology, papillary tumors are more likely to be suitable for NSS (20.8% of the cases in this series) than other histologic subtypes. The theoretical risk of multifocality that has been described in papillary tumors does not seem to impact recurrence and survival after NSS in this large contemporary NSS series. Excellent cancer control can be achieved with NSS when tumors are properly selected regardless of histologic subtype.

Seoul National University Bundang Hospital, Urology, Seongnam, South Korea, 2Seoul National University Bundang Hospital, Urology, Seongnam, Kyunggi-do, South Korea, 3Seoul National University Bundang Hospital, Pathology, Seongnam, South Korea, 4Seoul National University Hospital, Urology, Seoul, South Korea 1

Material & Methods: We retrospectively analyzed the records of 485 patients who received surgical management for organconfined or metastatic RCC. The presence or absence of tumor necrosis was evaluated based on macroscopic description of tumor (>10% macroscopic necrosis) (Figure). All gross finding of tumor necrosis (yellowish lesion within tumorous area) were confirmed by microscopic examination. With our study being a retrospective one, we did not try to analyze cases with microscopic tumor necrosis-only since we obviously did not have full control over initial sectioning of tumor for microscopic evaluation. To examine potential differences between patients with and without macroscopic tumor necrosis, chi-square test was applied. Cancer-specific and disease progression survival was estimated using KaplanMeier method. Log-rank tests were used to compare survival curves. Multivariate analysis was performed according to the Cox proportional hazards regression model to identify significant prognostic factors. Results: Macroscopic tumor necrosis was identified in 27% of total patients. Patients with macroscopic necrotic RCC were more likely to have larger tumor, metastatic disease, higher local stage, and higher tumor grade (all p<0.001). Pathologic features of microvascular invasion (p=0.026) and sarcomatoid differentiation (p=0.002) along with several laboratory findings were also observed to be associated with macroscopic tumor necrosis. Among the total subjects, patients without macroscopic tumor necrosis had significantly higher progression-free (p<0.0001) and disease-specific survival (p<0.0001) compared with patients otherwise. And, when survival analysis was limited to non-metastatic tumors only, same logic applied which was not the case for the patients with metastatic diseases (p>0.05). Among the different histologic subtypes of RCC, macroscopic tumor necrosis was observed to have significant impact only for clear cell subtype. In patients with non-metastatic RCC, multivariate analysis revealed that macroscopic tumor necrosis (p=0.004) was an independent prognostic predictor of disease-specific survival along with pathologic T stage, tumor grade, and tumor size. Conclusions: Our results suggest that macroscopic tumor necrosis may be a reliable prognostic indicator for nonmetastatic clear cell RCC which should routinely be examined for during pathologic analysis.

Eur Urol Suppl 2007;6(2):133