Changes in Renal Cell Carcinoma Pathologic Staging and Histologic Grading
Tumor categories are influenced by tumor size, but invasion of structures must be also considered.
The most important prognostic factor when treating renal cell carcinoma (RCC) is tumor staging. Larger tumors (greater than 4 cm to 5 cm) need to be carefully assessed for the possibility of renal sinus invasion, according to a new review published Surgical Pathology Clinics.1 Kanika Taneja,MBBS, MD, DNB, and Sean R. Williamson, MD, both of the Henry Ford Health System, Henry Ford Hospital in Detroit, Michigan, reported that pathologic primary tumor categories are influenced by tumor size. However, invasion of structures, including the renal sinus, perinephric fat, and the renal vein or segmental branches, must be considered when managing patients with RCC.
The authors noted that the invasion can be subtle. However, awareness of each patient's unique characteristics may be critical for clinical decision-making. The renal sinus contains abundant veins and lymphatics and it is theorized that this may provide increased opportunity for tumor dissemination compared with the perinephric fat.
The review examines the challenges in pathologic staging and grade reporting. It also discusses the latest updates on classification schemes from the World Health Organization and the American Joint Commission on Cancer. The researchers reported that the likelihood of renal sinus invasion increases dramatically with increased tumor size. Satellite nodules adjacent to or away from a large renal mass can indicate retrograde spread of tumor within vein branches, according to the authors.
The authors concluded by noting that the current American Joint Commission on Cancer staging system has modified the category of pT3a. It has removed the requirements that renal vein invasion be identified grossly and that vein walls must contain muscle to be categorized as pT3a.
- Taneja K, Williamson SR. Updates in pathologic staging and histologic grading carcinoma of renal cell carcinoma.Surg Pathol Clin. 2018;11:797-812. DOI:10.1016/j.path.2018.07.004