Prostate Cancer an Overview30

Is Sentinel Node Detection Helpful in the Curative Treatment of Prostate Cancer?

General Remarks

Prostate cancer accounts for 21% of all neoplasms in the male population in Germany (Schussler et al. 1993) and has similar rates of incidence in most countries in the Western world.

This cancer type has long been mentally connected with "old men's diseases," and the level of commitment to research aimed at the development of new diagnostic and therapeutic approaches to it has therefore been relatively low. Now, however, with increasing survival rates even in older age groups, interest in improving its diagnosis and treatment is growing. With new trends in N-stag-ing (see Wawroschek et al. 1999, 2000) in mind, it will be much more difficult to develop convincing strategies for detection of sentinel lymph node(s) (SLN), and it is also more difficult to dissect them, whether in isolation or together with secondary nodes within the pelvis, in the course of prostate cancer treatment than in the procedures used in breast cancer or malignant melanoma treatment.

The difficulties are connected mainly with problems in administering contrast agents for sentinel node detection and orientation in the local topography of the lymphatic network structures of the pelvis.

In addition, the problem is rendered more difficult because not only the lymph nodes must be dissected, but also the network of lymphatics in continuity with the prostate gland, which can contain cancer cells or cancer cell clusters.

Invasive and noninvasive imaging techniques have been flawed by unacceptably high false-positive and false-negative rates in most approaches (Loening et al. 1977; Wilson et al. 1977; McCarthy and Pollak 1991; Schussler et al. 1993).

In view to this fact and since we have no uniform and highly developed concept for detection of sentinel node(s) that is actually practiced by the majority of our urologists at present, systematic iliac and ob turator lymph node dissection is currently generally referred to as the "gold standard" when positive nodes are suspected, followed by prostatectomy in the case of confirmed prostate cancer.

As a rule of thumb, it is generally accepted and well documented that cancer-positive aortic nodes are connected with positive pelvic nodes and that at least in these cases it must be accepted that the condition is incurable.

As much as 20 years ago three different options for prostate cancer treatment in stage D1 were tested (radical prostatectomy, extended radiotherapy, and hormone therapy). The median survival in all groups was 39.5 months. None of the three treatment strategies was superior in prolonging life (Kramer et al. 1981), and there was no convincing breakthrough improving on this situation up to the 1990s.

New approaches to antiandrogen- and radioche-motherapy see Chapter 33.

Serum Values of Prostate-specific Antigen and Prostate Acid Phosphatase as Indicators for Cancer, Metastatic Spread and Cancer Recurrence

Bluestein et al. (1994) follow from their investigations on 1632 patients that prostate-specific antigen (PSA) is the best predictor of pelvic lymph node metastases (P <0.0001).

Definition of the Degrees of Malignancy in Gleason's Grading (Scoring) System

This section starts with a detailed analysis of the grading strategy (characteristic features of the subgroups).

The predictive power is enhanced by considering the Gleason grading (scoring) (P <0.001) and

Table 1. Gleason grading system for prostatic adenocarcinoma: histologic patterns

Pattern

Peripheral borders

Stromal invasion

Appearance of glands

Size of glands

Architecture of glands

Cytoplasm

l*

Circumscribed expansive growth

Minimal Simple, round, Medium, Closely packed Similar to that monotonously regular in benign replicated epithelium

2 *

Less circumscribed; early infiltration

Mild, with def- Simple, round, Medium, less Loosely packed Similar to that inite separa- some variabil- regular rounded in benign tion of glands ity in shape masses epithelium by stroma

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