Primo N. Lara Jr., Eric Jonasch (Eds). Kidney cancer. Principles and practice. Springer-Verlag (2012)
Kidney cancer remains the most lethal of all urologic cancers with over 20% of patients diagnosed with kidney cancer succumbing to the disease. Despite a notable increase in early detection and extirpative surgery for localized kidney cancer, RCC-related mortality continues to rise [2, 6]. The implication is that while a fraction of RCC is aggressive and potentially lethal, a large proportion of early stage RCC provides little, if any, impact on patient survival.
There are very limited level I data regarding optimal management of early stage RCC. A recent meta-analysis of published data on the management of SRMs provides further confirmation that SRMS can be effectively managed with nephron-sparing surgery NSS, thermal ablative or active surveillance. Furthermore, a delay in surgical therapy for SRMs does not appear to affect cancer-specific survival. This leads to an important question as to whether this level of aggressive therapy alters the natural course of SRMs.
Moreover, as oncologic data have demonstrated an equivalency of nephron-sparing surgery to RN, increased attention has focused on nephron preservation and the underutilization of NSS techniques. A recent examination of the National Cancer Database (NCDB) from 1993 to 2005 revealed that only 27.1% of tumors <4.0 cm were being treated with NSS techniques. At the beginning of this time period, a paltry 5.9% of T1a lesions were being treated with NSS approaches. The SEER registry data shows similar trends. Examining the SEER data from 1999 to 2006 for over 18,000 lesions <4.0 cm, the rate of PN only increased from 20.0% to 40.0%. Finally, an analysis of over 66,000 patients from the Nationwide Inpatient Sample from 1988 to 2002 revealed a 7.5% national rate of PN.
An important focus of modern day oncologic practice is not solely on cancer-specific survival, but also on assessment of competing risks and their impact on clinical decision-making. Considering the natural history of early stage RCC, the benefit of surgical treatment depends in large part on an analysis of competing risks. In that respect, clinically localized RCC mimics early stage prostate cancer in that it challenges the urologist to account for comorbidities that may contend with CSS. Recently published reports indicate that Charlson comorbity index scores are useful prognosticator of survival patients with localized kidney tumors. Surgical resection of SRMs with Charlson index scores >2 appears to provide no survival advantage. This implies that the severity of comorbidities, rather than the tumor itself, dictates outcomes in early stage RCC.
Using the SEER database, a first comprehensive nomogram estimating competing risks of death from localized RCC versus other cancer and noncancerrelated mortality came out in early 2010. This prediction model demonstrates that patients with localized node-negative kidney cancer have an excellent 5(96%) and 10-year (93%) cancer-specific survival, while a significant 5and 10-year overall risk of death from other cancers (7%, 11%) and noncancer-related mortality (11%, 22%) exists. Furthermore, tumor size was a significant predictor of RCC-related death. Age, however, was a strong predictor of non-RCC-related death.
As surgical expertise in treatment of SRMs continues to evolve so does the concept of individualized patient treatment that integrates age and existing comorbidities. Although surgical treatment of SRMs is still heralded as the “gold standard,” newly published AUA guidelines support active surveillance for appropriately selected patients with decreased life expectancy and extensive comorbidities. Therefore, the use of objective tools, such as statistical models, nomograms, and Nephrometry, for objectifying risk should become standard and not simply an option.