Renal cell carcinoma with venous tumor thrombus extension: A retrospective study of factors affecting survival, "Beyond the Abstract," by Kazuto Ito, MD, PhD and Mikio Kobayashi, MD, PhD

BERKELEY, CA (UroToday.com) - Although the percentage of patients with renal cell carcinoma (RCC) extending into venous systems is unexpectedly high, the prognostic impact and independency of venous tumor thrombus-related factors on overall survival (OS) remain controversial. In general, predicting prognosis of patients with very advanced stages of cancer is difficult because multifactorial issues are often involved. In the viewpoint of clinicians, it is known that some clinicopathologic factors affect short-term survival while others are related to long-term survival. Controversy regarding the prognostic impact of tumor thrombus in patients with RCC may be at least partly due to the difference in the follow-up duration of the recruited data in the previous studies. To address the impact of classical clinicopathologic factors, levels of tumor thrombus, venous wall invasion, and also likelihood of aggressive cytoreductive operation in patients with RCC with venous thrombus on short-term and long-term overall survival, the present comprehensive univariate and following multivariate statistical analyses were conducted using multi-institutional data provided by 17 hospitals belonging to the Japanese Society of Renal Cancer.

Between 1980 and 2009, 292 patients diagnosed with RCC with venous tumor thrombus were retrospectively registered for this study. We investigated prognostic impacts of various clinicopathologic and surgical treatment factors including levels of venous thrombus, venous wall invasion status, and surgical categories that were classified into five groups according to the operative management at the tumor origin, tumor thrombus, and metastatic sites. Kaplan-Meier method and following multivariate Cox proportional hazards model were used to explore predictors on overall survival in all 292 participants. To clarify whether prognostic factors change with elapsed postoperative follow-up years, impacts of the above-indicated clinicopathologic factors were investigated for patients who were alive at 1, 2, and 3 years of follow-up using multivariate Cox proportional hazards model. Furthermore, the prognostic impacts of the above clinicopathologic factors were also assessed using restricted data until 1, 2, and 3 years of follow-up in order to investigate the impact of follow-up duration on statistical analyses of prognostic factors. This unique analysis, using restricted follow-up data, may clarify prognostic factors that affect short-term and/or long-term survival.

The median follow-up duration was 40.4 months. A total of 133 patients died due to RCC and 14 cases due to other causes. Death within one month after operation or diagnosis was seen in 2 (18.2%) of 11 patients who did not undergo operation and in 8 (2.8%) of 281 patients who underwent any operations. The 1-, 3-, 5-year OS and CSS, respectively, were 77.4% and 79.0%, 55.2% and 58.4%, and 47.6% and 50.9%. Several independent predictive factors were identified in each subgroup analysis in terms of yearly-based survival and restricted follow-up duration. The presence of tumor thrombus invading to venous wall was independently related to OS in the full-range follow-up data and in survivors at 2 and 3 years of follow-up. Using restricted follow-up data until 1, 2, and 3 years of follow-up, many independent predictive factors changed with follow-up duration, but surgical category could be a universal and independent predictive factor.

In patients diagnosed with an advanced stage of RCC with a tumor thrombus, many important independent predictive factors were identified in each subgroup analysis in terms of restricted follow-up duration and yearly-based survivors. However, the most universal factors affecting improvement of both in short-term and long-term survivals in RCC with venous thrombus could be feasible aggressive cytoreductive surgery and absence of venous wall invasion even in a case of metastatic disease. It may mean that the best available cytoreductive operation following more reliable preoperative imaging for predicting venous wall invasion status would improve OS for patients with advanced RCC extending into venous systems.

Written by:
Kazuto Ito, MD, PhDa and Mikio Kobayashi, MD, PhDb as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.

a Associate Professor, Department of Urology, Gunma University Graduate School of Medicine, 3-39-22, Showa-machi, Maebashi, Gunma, 3718511, Japan
Division of Urology, Isesaki Municipal Hospital, 12-1, Tsunatori-hon-machi, 372-0817 Isesaki, Gunma, Japan

Impacts of clinicopathologic and operative factors on short-term and long-term survival in renal cell carcinoma with venous tumor thrombus extension: A multi-institutional retrospective study in Japan - Abstract

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