[1007] Ductal Adenocarcinoma of the Prostate in 1051 Radical Prostatectomy Specimens. Histopathological Features and Prognostic Relevance

Amanda Seipel, Fredrik Wiklund, Peter Wiklund, Lars Egevad. Karolinska Institutet, Stockholm, Sweden

Background: Ductal adenocarcinoma of the prostate (DAC) is a histological subtype of prostatic carcinoma thought to be associated with a relatively poor prognosis. The prevalence of DAC varies widely in the literature (0.4% - 12.7%). We aimed to evaluate the prognostic significance of histopathological patterns of DAC and to identify relevant diagnostic criteria.
Design: 1156 men underwent radical prostatectomy at the Karolinska Hospital 1998 - 2005. Men with neoadjuvant treatment or unavailable slides or follow-up were excluded and 1051 cases remained for review. Tumors were classified as DAC of classical type (DACC), borderline type (DACB) or prostatic carcinoma with ductal features (PCDF). A DACC had tall, columnar, pseudostratified epithelium, elongated, oval nuclei with prominent nucleoli, papillary, glandular or cribriform architecture and more than focal extent. A DACB showed most features but lacked elongated nuclear shape or classical architecture. A PCDF lacked elongated nuclei and had either DAC-type architecture or pseudostratified epithelium with high-grade atypia. Cox models were used to assess association of DAC subtypes and histopathological features with biochemical recurrence.
Results: DACC, DACB and PCDF were seen in 2.6% (27), 4.0% (42) and 1.6% (17) of 1051 radical prostatectomy specimens. DAC was almost always mixed with prostatic acinar adenocarcinoma (PAC) and only 0.2% (2/1051) contained pure DAC. Papillary, glandular and cribriform architecture was seen in 72%, 36.6% and 62.2%. Zonal origin was peripheral, transition, central zones or unclear in 57%, 7%, 1.2% and 34.8%. Location was periurethral, peripheral or both in 69.8%, 3.5% and 26.7%. DAC constituted 10% - 100% (mean 40%) of the main tumor. Necrosis was seen in 31.3%, stromal invasion of DAC in 52.3% and intraductal spread in 91.9%. In assessment of biochemical recurrence, DACC, DACB och PCDF had a HR of 1.5 (0.8-2.9), 1.4 (0.8-2.5) and 1.2 (0.5-2.7), respectively. Location, % DAC, necrosis, stromal invasion or GS of PAC component were not predictive of recurrence. In DACC/DACB and PAC, extraprostatic extension was seen in 66.7% and 42.4% (p <0.001) and seminal vesicle invasion in 13.0% and 5.0% (p = 0.0045), respectively.
Conclusions: The results suggest that DAC is more aggressive than an average PAC. It is proposed that DAC should include DACC and DACB, thus 6.6% of all prostate cancers. Cancer with DAC type architecture only and cancer with conventional architecture and pseudostratified high-grade epithelium without elongated nuclei should not be included in DAC.
Category: Genitourinary (including renal tumors)

Wednesday, March 21, 2012 1:00 PM

Poster Session VI # 167, Wednesday Afternoon

 

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