Solitary, isolated metastatic disease to the kidney: Memorial Sloan-Kettering Cancer Center experience

Study Type – Therapy (case series) Level of Evidence 4 What’s known on the subject? and What does the study add? Usually malignant disease involving the kidneys is characterized by bilateral and multiple lesions in association with widespread dissemination of the primary tumour. Metastasis to the kidney as a solitary, isolated renal mass is an extremely rare event and little is known about its characteristics and outcomes. Our study shows that kidney involvement by other tumours can occur as isolated solitary lesions and the kidney can be the first and only site of metastatic involvement. Of the 14 patients included in the study, 8 were alive at the last follow‐up and 4 without evidence of disease after nephrectomy. In this highly selected group of patients nephrectomy can be offered as a therapeutic option.

OBJECTIVE

? To analyse the clinical characteristics and outcomes of patients who underwent nephrectomy for solitary, isolated metastatic disease to the kidney.

PATIENTS AND METHODS

? From July 1989 to July 2009, we identified 13 patients who underwent nephrectomy for solitary metastasis to the kidney. Patients’ demographics, intra‐operative variables and outcomes are reported.

RESULTS

? The median age at nephrectomy was 52 years (range 33–79). Eleven patients (85%) had an incidentally discovered renal mass, whereas two patients (15%) presented with gross haematuria. ? Median time from initial surgery at the primary site to development of metastatic disease to the kidney was 63 months (range 9–136). No patient had evidence of disease at other sites at the time of nephrectomy. In seven patients (54%), the kidney was the first site of recurrence. ? The most common primary site was the lung in five patients (38%), followed by the colon in two (15%), chest wall in two (15%) and bone, brain, breast and salivary gland in one patient each (8%). ? Of the 14 procedures performed, eight (57%) were partial nephrectomy (PN) and six (43%) were radical nephrectomy (RN). ? Four patients died after progression from the primary tumour, all within 2 years of nephrectomy. One patient with a primary chondrosarcoma had no evidence of disease at last follow‐up and died from other causes 50 months after nephrectomy. The median follow‐up for the eight patients who were alive at last follow‐up was 30 months after nephrectomy. Four of these patients had no evidence of disease and four patients were alive with metastatic disease.

CONCLUSION

? Kidney involvement by metastatic disease can occur as isolated solitary lesions. Some patients will also have the kidney as the first and only site of metastatic involvement. The presence of an isolated renal metastasis should not be considered an end‐stage disease, and nephrectomy can be offered for highly selected patients as a therapeutic option.