Classification of prostate cancer
The determination of the tumor type (Typing) usually yields an adenocarcinoma (glandular cell cancer). Meanwhile malignancy (malignancy) is classified (grading) and most commonly known as Gleason score indicated.
Enables the physician to select the correct treatment and make a correct prediction, the tumor must be classified. Because the different tumors show a very different behavior in the growth and spread.
In order to classify a pathologist working on the removed tissue from the prostate and examined microscopically, and possibly also with other methods. The fabric may consist of a biopsyderived (see test ) or an operation (such as radical prostatectomy , TUR-P = transurethral resection of the prostate). Important for the evaluation of the structure of the fabric (arehistology ) and the appearance of the cells ( cytology ).
Typing: determination of tumor type
According to the WHO classification (and other classification systems, WHO = World Health Organization, World Health Organization), a distinction benign tumors and precancerous lesions of the malignant tumors of the prostate. To the first two groups include:
- AAH (atypical adenomatous hyperplasia): suspicious tissue
- ASAP (atypical small acinar proliferation engl. = atypical proliferation mikroazinäre): suspicious tissue
- LG-PIN (german low grade prostatic intraepithelial neoplasia, PIN = mild): Harmless changes
- HG-PIN (engl. high grade prostatic intraepithelial neoplasia, high-grade PIN =): Possible cancer precursor (precancer)
The malignant tumors are further classified according to their origin in:
- Epithelial tumors (most common): You go from epithelial cells (surface cells, including glandular cells) and are therefore referred to as prostate cancer (for details see below).
- Sarcomas (very rare): They arise from cells of the interstitial tissue of the prostate (eg, muscle cells, connective tissue).
- Secondary tumors (very rare): You grow out of the neighborhood in the prostate or are metastases (secondary tumors) of malignant tumors elsewhere in the body.
So lower prostate cancer refers only epithelial tumors. At least 90% of them are ordinary prostate cancers that arise from glandular cells and are therefore called adenocarcinomas.The few remaining, unusual prostate cancers may also be derived from other epithelial cells.
Grading: grading of malignancy
The malignancy (malignancy) of prostate cancer depends and which the tumor type, how much different tissue architecture and cells from normal tissue of origin in the prostate: For small deviations is known as a highly differentiated (little dedifferentiated) tumors, with strong deviations from a poorly differentiated (= strongly dedifferentiated) tumors.
And the malignancy of the tumor increases with its dedifferentiation. This is shown by irregular cells and a disorganized growth pattern (eg sieve-like cribriform =). Microscopic and with various special method thus can be distinguished from each other many subtypes of prostate cancer.
The aim of grading (of English. = Grade to grade) is to systematically identify the differences between cancer and normal tissues, and thus the degree of malignancy to determine (the degree of malignancy). Here are a few organizations ("Grading") systems have been developed. In addition to the TNM grading they apply only to adenocarcinomas and consider tissue samples and cell results in varying degrees:
TNM grading: The TNM system (s growth and spread ) also includes a classification into high (G1), moderately (G2) and poorly (G3-4) differentiated prostate cancers.
Gleason score: The classification according to Gleason is the most common and should be used in all ordinary prostate. It includes five different growth patterns described accurately and according to increasing deviation from normal tissue from 1 (= low) to 5 (= strongly) evaluated (see figure). The assignment of the score (English score) is done separately for the primary (main) and the secondary (more) pattern. The Gleason score then the sum and the individual scores are given: For example, pattern 2 pattern 3 plus the same Gleason score 5, abbreviated 5 (2 +3). The lowest grade of malignancy accordingly has a Gleason score of 2 (1 +1), the highest one of 10 (5 +5).
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