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The majority of patients with metastatic renal cancer (mRC) experience reduced renal mass (RRM) prior to starting systemic anticancer treatment (SAT) due to the local burden of the primary tumor and/or local treatment. Patients who have undergone local treatment for renal carcinoma are at increased risk for acute kidney injury (AKI) and for the progression of chronic kidney disease. A percutaneous renal biopsy (PRB), which is relatively contraindicated in patients with a solitary kidney (SK), serves as a reference method for assessing renal toxicity. The pathological findings of kidney disease in AKI may impact the cancer treatment plan. However, data on the safety of PRB in this patient population is lacking. In this study we aim to assess the safety of PRB for AKI in mRC patients with RRM.
We retrospectively analyzed the incidence of complications related to PRB for AKI in mRC patients with RRM and assessed the associated risk factors. All biopsies were performed under ultrasound guidance by the nephrologist in patients with clinical evidence of AKI and no other formal contraindications for PRB
A total of 13 PRBs were performed in 12 patients. 10 patients had SKs, one had RRM due to a partial nephrectomy, and one had RRM due to the primary tumor (Table 1). All patients received SAT before PRB. 11 patients had renal cell carcinoma and one had urothelial carcinoma. At the time of PRB, none of the patients had liver disease and six patients had proteinuria of >1 g/day. Prior to PRB, one patient underwent acute hemodialysis due to AKI and one required an erythrocyte transfusion. In two obese patients, the depth of the kidney that the needle passed through was >10 cm. After PRB, the patients were observed for at least 24 hours, and all of them underwent a follow-up ultrasound examination, which revealed an arterio-venous (A-V) fistula in one patient. Seven days after PRB, this patient experienced massive urinary bleeding, which led to hemodynamic instability. He underwent emergent coiling of the A-V fistula and received an erythrocyte transfusion. The patient fully recovered without needing a surgery. In all other PRBs, no complications were observed.
Table 1. Characteristics related to patients or biopsies (12 patients, 13 biopsies)
Legend: BMI, body mass index; INR, international normalized ratio; Q, quartile;
PRB, percutaneous renal biopsy.
Characteristic
Median (Q1-Q3)
Age (years)
68 (61.5–73.5)
Creatinine (mmol/L)
213 (186–245)
Proteinuria (g/day)
0.25 (0.20–1.95)
Hemoglobin (g/L)
10.8 (10.6–11.8)
Platelet count (x 1,000/µL)
209 (125–277)
INR
1.05 (0.93–1.13)
Bipolar kidney diameter (cm)
11.5 (11.0–13.3)
Parenchymal thickness (cm)
1.8 (1.5–2.0)
Depth of the biopsied kidney (cm)
5.0 (3.5–9.0)
Proportion in %
Gender (male/female)
31/69
Biopsied patients undergoing hemodialysis
8
Biopsy side (left/right)
46/54
Biopsy passes (1/2/3/4)
0/54/31/15
BMI ≥30 kg/m2
46
Patients receiving antiplatelet treatment during PRB
Patients receiving corticosteroids during PRB
31
Patients with arterial hypertension ≥160/90 mmHg
15
Patients receiving antithrombotic therapy before PRB
38
In our cohort of 12 mRC patients with RRM in whom 13 PRBs for AKI were performed, one major bleeding complication occurred. The complication was manageable, the patient fully recovered. A longer period of observation for complications after PRB may be needed in mRC patients with RRM than in the general population. Well-designed studies with a larger number of mRC patients with RRM in whom PRB is indicated are needed.