C-reactive protein: A clinically useful biomarker in renal cell carcinoma

■ A large percentage of patients with kidney cancer will present with or develop metastases. Metastatic spread is the greatest predictor of mortality.


■ Emerging aggressive treatment can improve survival in some patients who develop metastases, but this treatment relies on early detection.


■ While traditional TNM staging remains integral in prognosis of kidney cancer, it has significant limitations.


■ Preoperative and postoperative biochemical markers of inflammation, specifically CRP, serve as adjuncts to TNM staging to help identify patients at increased risk for recurrence. These tools should help guide intensity of counseling, follow-up surveillance of recurrence, and enrollment in clinical trials.


CASE


Two patients were referred to our urology clinic for staging and management of renal masses. Patient 1 was a 68-year-old white female with a body mass index (BMI) of 21.3 kg/m². 
MRI revealed a renal mass measuring 7.0 × 7.9 × 8.0 cm invading the right renal vein and extending to the inferior vena cava (IVC). Clinical staging suggested locally invasive disease in the absence of nodal or distant metastases. On resection, the mass measured 8.2 cm, and the diagnosis was grade 4 clear cell kidney cancer T3N0M0. Histologically, the mass demonstrated negative surgical margins, absence of invasion into the IVC wall, and absence of nodal metastasis. In addition to traditional TNM staging, we assessed inflammatory status by measuring the serum C-reactive protein (CRP). The initial CRP level (which we used as our "pre­operative" value) was 215.46 mg/L (Table 1). 


Patient 2 was a 46-year-old white male with a BMI of 19.0 kg/m². MRI revealed a renal mass measuring 11.0 × 11.1 × 11.0 cm and extending through the renal vein to the IVC. Clinical staging suggested locally invasive disease in the absence of nodal or distant metastases. On resection, the mass measured 7.9 cm, and the diagnosis was grade 3 clear cell kidney cancer T3N0M0. Histologically, the mass demonstrated negative surgical margins, absence of invasion into the IVC wall, and absence of nodal metastasis. Patient 2's initial CRP level was 163.7 mg/L (Table 1).


Both patients presented with similar disease states: locally invasive kidney cancer without known nodal or distant metastases. Therefore, both patients underwent potentially curative radical nephrectomy. In both cases, the diseased kidney and associated adrenal glands were removed. Addi­tionally, draining lymph nodes were removed and analyzed pathologically for nodal metastasis. Pathologic analyses revealed a lack of nodal spread in both patients. 


The two patients were followed postoperatively. At each visit, serum CRP levels were measured and CT scans performed to identify metastases. Patient 1's CRP levels declined precipitously, falling to less than 10 mg/L at 1 month postoperatively (Table 1). Patient 1 survived the first year after diagnosis without recurrence of disease. Patient 2's CRP levels remained higher than 100 mg/L postoperatively (Table 1). He developed lung metastases 4 months after surgery and died 7 months after surgery.