Illustrative case series

Management of an Asymptomatic Renal Mass in a 78-Year-Old Man with Comorbidities

By William B. Ershler, MD

An asymptomatic 78-year-old retired accountant presented to his physician with intractable hiccups. Physical examination, complete blood count, and imaging studies did not reveal a cause of the hiccups, and after several days the symptom disappeared. However, upon review of the abdominal CT scan obtained in evaluation of the hiccups, a right renal mass was defined.

The patient was not experiencing flank pain, constitutional symptoms, or hematuria. He has a known history of atherosclerotic cardiovascular disease, hypertension, coronary artery disease, and type II diabetes mellitus. Three years prior to this visit he had suffered a cerebrovascular accident and despite aggressive physical therapy, he remains with residual right-sided upper and lower extremity weakness. Nonetheless, he lives at home with his wife and enjoys a reasonably good quality of life.

The CT of the abdomen after oral but not intravenous contrast revealed an upper pole right renal lesion measuring 4.7 cm x 3.7 cm that was not cystic. There was no apparent hydronephrosis. The left kidney was unremarkable. The chest and abdominal CT also revealed changes consistent with diffuse atherosclerosis, but there was no evidence for pulmonary parenchymal nodules, lymphadenopathy, or skeletal metastases.

The patient was referred for advice regarding additional work-up and treatment.

DISCUSSION

This patient presents with an incidental asymptomatic renal mass that slightly exceeds what is conventionally considered a small renal mass (largest dimension of 4 cm).1,2 The discovery of such masses has become increasingly common with the widespread use of cross-sectional abdominal imaging.3 In fact, the incidental detection of asymptomatic lesions now accounts for > 50% of all renal masses discovered.4 Of these, approximately 80% are malignant and 20% are benign.5

Needle biopsy — once considered too risky — has reappeared at some institutions and has been accomplished safely when performed by CT-guided technique.6 Although specificity is excellent, for smaller masses (< 3 cm) sensitivity (false negatives) remains a concern and it is unclear to what extent biopsy results influence subsequent management.

Traditionally, patients with small renal masses have undergone radical nephrectomy. However, for patients with preexisting renal impairment, nephrectomy may predispose patients to clinically important renal insufficiency and associated outcomes, including increased cardiovascular risk and even shortened overall survival.7 Accordingly, nephron-sparing surgical approaches8 and directed thermal ablation procedures9 have been developed.

Although the 5-year cancer-specific survival rate for patients with surgically treated stage I small renal masses (SRMs) remains in excess of 95%,10 alternative approaches clearly are warranted for some, particularly those with compromised renal function or with significant comorbidities. This is because the natural history of small renal masses is incompletely understood. Although it is true that approximately 80% are malignant, it is also true that many will be low grade and unlikely to progress to clinically important disease. Thus, active surveillance is an alternative approach incorporating scheduled repeat imaging and additional intervention as warranted by interval change. Although no universally accepted active surveillance protocol has been established by prospective randomized trial, there have been a number of retrospective observational reports that were nicely summarized in a recent review.11 From this review it is clear that a substantial proportion (23%) of small renal masses remain static at least over the first several months to few years, and only a small percentage of the overall population (2%) develop metastatic disease while under surveillance. Factors that predicted growth and spread included initial size and the rate of growth as observed on serial imaging studies. For example in this analysis, those who ultimately developed metastatic disease had an annual mean linear growth rate of 0.8 cm + 0.7 cm compared with 0.3 cm + 0.4 cm for those who did not.

RECOMMENDATIONS

The patient presented was elderly and with significant comorbidities, including atherosclerosis and diabetes. Although renal function parameters were not presented, it would be safe to assume that he would be at greater than average risk for significant renal insufficiency after nephrectomy. Furthermore, his risk of dying as a result of his comorbidities may well outweigh any benefit from intervention.12 On the other hand, the renal mass was larger than what might be considered "small," and it would be reasonable to expect he would have a higher than average chance of developing progressive disease and metastases during active surveillance. At any age, in a patient without comorbidity, my inclination would be nephrectomy, particularly because of the size of the lesion at presentation and in light of the published experience as reviewed.11 However, in this older patient with significant comorbidity, active surveillance would seem appropriate. If there is above-average linear growth (i.e., > 0.3 cm/year) over the first year and if the patient were to remain medically stable from his comorbid illnesses, partial nephrectomy would also offer a reasonable chance of cure from this disease.

References

1. Gill IS, et al. Clinical practice. Small renal mass. N Engl J Med 2010;362:624-634.

2. Volpe A, et al. The natural history of incidentally detected small renal masses. Cancer 2004;100:738-745.

3. Hollingsworth JM, et al. Rising incidence of small renal masses: A need to reassess treatment effect. J Natl Cancer Inst 2006;98:1331-1334.

4. Jayson M, Sanders H. Increased incidence of serendipitously discovered renal cell carcinoma. Urology 1998;51:203-205.

5. Frank I, et al. Solid renal tumors: An analysis of pathological features related to tumor size. J Urol 2003;170(6 Pt 1):2217-2220.

6. Volpe A, et al. Techniques, safety, and accuracy of sampling of renal tumors by fine needle aspiration and core biopsy. J Urol 2007;178:379-386.

7. Go AS, et al. Chronic kidney disease and the risks of death, cardiovascular events, and hospitalization. N Engl J Med 2004;351:1296-1305.

8. Gill IS, et al. Comparison of 1,800 laparoscopic and open partial nephrectomies for single renal tumors. J Urol 2007;178:41-46.

9. Gill IS, et al. Renal cryoablation: Outcome at 3 years. J Urol 2005;173:1903-1907.

10. Campbell SC, et al. Guideline for management of the clinical T1 renal mass. J Urol 2009;182:1271-1279.

11. Smaldone MC, et al. Small renal masses progressing to metastases under active surveillance: A systematic review and pooled analysis. Cancer 2012;118:997-1006.

12. Kutikov A, et al. Evaluating overall survival and competing risks of death in patients with localized renal cell carcinoma using a comprehensive nomogram. J Clin Oncol 2010;28:311-317.