Die mikroskopische Gefäßinvasion als Prognosekriterium für das Langzeitüberleben von Patienten mit Nierenzellkarzinom ohne makroskopische Gefäßinvasion

After the prostate- and bladder cancer renal cell carcinoma is the third most common urological malignancy with an increasing incidence and the highest mortality rate. Despite well established prognostic factors which affect the progression and survival of patients with renal cell carcinoma like pathological stage and nuclear grading, the clinical course and outcome of this disease often remains unpredictable with late recurrence and development of metastasis. Therefore, we still need further prognostic criteria to define high-risk patients to offer them a closed-mashed or extended surveillance. In the present study we retrospectively evaluated 392 patients with localized tumors (stage pT1 to pT3a) who underwent surgical treatment for renal cell carcinoma in the Department of Urology at the University of Marburg between 1990 and 2000 with respect to the influence of microscopic venous invasion on disease-specific survival and the association with other clinical and pathological features. A second review of all original slides was performed by an experienced local pathologist to re-evaluate the presence of a microscopic venous invasion in the primary tumor, after the original pathological report in the patients’ files described a microscopic venous invasion in 16 (3%) cases, only. Within the pathological review 80 patients were excluded from the study as a sufficient assessment of the slides was unfeasible. In 46 of 312 (14,7%) cases a microscopic venous invasion was present. Median follow-up was 77 month. Microscopic venous invasion was significantly associated with tumor stage (p<0,001), nuclear grade (p=0,006), the presence of lymph nodes metastasis (p<0,001), and the survival code (p=0,001) with a significant higher percentage of disease-related deaths in the group with microscopic venous invasion. Using Kaplan-Meier analysis, a statistically significant difference in cancer-specific survival was observed according to the presence or absence of microscopic venous invasion (p<0,001). The 5-year cancer-specific survival rates were 61% and 91% for patients with or without microscopic venous invasion, respectively. Applying multivariate analysis there was only a trend for microvascular invasion to be an independent prognostic criteria (p=0,075, cox regression analysis; HR 1,82, 95% CI 0,94-3,51) for cancer-specific survival in patients with renal cell carcinoma, however, we could not obtain statistical significance in the present cohort. In contrast, the multivariate analysis confirmed the common and well established prognostic criteria tumor stage, nuclear grading and presence of distant metastasis as independent predictors of cancer-specific survival. According to our findings microvascular invasion affects survival in patients with renal cell carcinoma (without macroscopic venous involvement), however it failed to independently predict cancer-specific survival in these patients. There is the need for further investigations about the influence of microscopic venous invasion according to different tumor stages and histological subtypes on the prognosis of kidney cancer patients in larger cohorts and prospective trials, if possible.