Implementation of a map in radical prostatectomy specimen allows visual estimation of tumor volume
Introduction
The increasing importance of standardization in the medical world has led to the introduction of a standardized sectioning protocol and standardized documentation of radical prostatectomy specimens in our center. Consequently, we developed a special method for mapping radical prostatectomy specimens. Mapping of prostate cancer is an elegant and practicable method to exactly document tumor extension, extracapsular tumor growth, and the surgical margins of a radical prostatectomy specimen.
In the past, TNM classification has undergone several changes concerning tumor stages of prostate carcinoma. The actual AJCC TNM staging system separates tumors based on whether they involve less than one-half of one lobe (pT2a), more than one-half of one lobe (pT2b), or both lobes (pT2c). While this stratification may be useful in the clinical assessment of prostatic adenocarcinoma, the vast majority of tumors, at least focally, involve both lobes, and very small and very large tumors are stratified into the same stage pT2c.1 Besides the important use for the clinician to get a quick overview of the stage of the prostate cancer, which is independent from changes in the TNM classification, the mapping of prostate cancer offers an elegant way to document multifocal cancer, prostatic intraepithelial neoplasias (PIN) and other lesions, which might be of scientific interest.
The aim of this study was to investigate if our model of mapping prostate cancer may serve for visual estimation of tumor volume.
Tumor volume is one of the best documented prognostic factors for prostate cancer. It was shown to positively correlate with pretreatment serum levels of prostate-specific antigen (PSA), histological grade, DNA aneuploidy, extension of capsular penetration, pathologic stage, positive surgical margins, presence of pelvic lymph node metastases, risk of failure after therapy, and risk of death from prostatic cancer in univariate analysis.1 Nevertheless, tumor volume could not be demonstrated as an independent prognostic factor in multivariate analysis.2, 3 There are several methods to estimate prostate carcinoma volume, including estimation based on visual inspection or grid morphometric analysis, measurements of the dimension of the largest tumor focus or maximum tumor dimension, approximation of the tumor volume in three dimensions, and computer-assisted image analysis.1, 2, 3, 4, 5, 6, 7, 8, 9 Clearly, the latter represents the most accurate method; however, it would lack practicability if employed in each and every hospital on a routine basis. Accordingly, we chose a simple method, namely mapping of radical prostatectomy specimens to combine documentation and elaboration of prognostic significant parameters for clinical outcome after radical prostatectomy.
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Patients and methods
Between 2000 and 2002, 350 radical prostatectomy specimens from patients with previously untreated prostate cancer were obtained from our urological clinic. None of the patients had undergone neoadjuvant hormonal therapy. Before surgical intervention prostate cancer had to be proven histologically by biopsy; metastasis, except lymph node metastasis, were excluded clinically. Every patient was treated with primary retropubic radical prostatectomy following lymphadenectomy.
Results
The age of the patients ranged from 51 to 81 years (mean 68). Mean time of follow up was 34 months with a median of 39 and a range between 1 and 67 months. Four patients died during follow up; all deaths were unrelated to prostate cancer. Tumor volumes ranged from 1 to 59 cm3. Mean tumor volume was 11 cm3. The median of all tumor volumes was 7 cm3. One-hundred and seventeen cases showed positive margins upon histomorphological examination. Twenty-nine patients showed a positive lymph node staging in
Discussion
Adenocarcinoma of the prostate remains highly unpredictable in its clinical course in the individual patient and radical prostatectomy remains an important therapy to treat patients with clinically organ-confined prostate cancer beside LDR brachytherapies.13 Most of the definitions of clinically significant versus clinically unimportant prostatic carcinomas incorporate tumor size measurements.14, 15, 16, 17, 18, 19, 20, 21, 22
There are many different methods to evaluate tumor volume of prostate
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