Partial Nephrectomy for Managing Small Renal Masses

By Paul Russo, MD, FACS,

Thursday, February 19, 2015

In years past, radical nephrectomy — removal of the entire kidney along with surrounding soft tissues and lymph nodes — was the standard approach to treating all kidney tumors. And while this method is still required when surgeons encounter massive and locally advanced tumors, surgical management of small renal tumors has evolved a great deal. Today, partial nephrectomy is chosen whenever technically feasible. (1)

Memorial Sloan Kettering surgical staff has led the global evolution to partial nephrectomy for small renal masses following years of clinical and surgical research. Our approach to small kidney tumors emphasizes using the right amount of surgical intervention to achieve local control while preserving vital kidney function to the fullest extent possible. While taking into account key surgical selection factors, including the age and medical condition of the patient and the tumor’s location and proximity to critical vascular structures, we are able to perform partial nephrectomy in over 90 percent of patients with T1 tumors (7 cm or less), whereas the national average is only 30 percent.

This shift in approach is significant because approximately 70 percent of the estimated 63,920 new cases of kidney cancer reported in the United States in 2014 will consist of small tumors (median size < 4 cm). Most will be detected incidentally during the evaluation of abdominal or musculoskeletal complaints, or during care for an unrelated cancer.

An added incentive for expanding elective partial nephrectomy is that up to 45 percent of resected tumors are benign or have indolent pathology with limited metastatic potential.

The Case for Partial Nephrectomy

Evidence from many clinical series has demonstrated that partial nephrectomy provides local tumor control and survival rates equivalent to radical nephrectomy for T1 tumors (2) (3), with the added benefit of preservation of kidney function and prevention of chronic kidney disease (CKD). (4) CKD — which affects 30 million Americans and is already present in one in three patients with kidney tumors — can be caused by hypertension, cigarette smoking, and common diseases such as diabetes and is associated with increased cardiovascular morbidity and mortality over time. Radical nephrectomy can cause or worsen CKD. (5)

A pooled analysis of the world’s literature comparing elective partial to radical nephrectomy based on 51 studies involving more than 31,000 patients demonstrated that the former was associated with a 19 percent reduction in all-cause mortality, a 29 percent reduction in cancer-specific mortality, and a 61 percent reduction in CKD. (6)

7.5 cm (T2) exophytic upper pole renal mass amenable to partial nephrectomy

Best-practice guidelines from both the United States and Europe now support elective partial nephrectomy for T1 renal tumors (7 cm or less). (7) Increasingly, partial nephrectomy is also being performed for larger tumors (T2), particularly when located in the polar regions of the kidney (8) (Figure 1).

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Evolution of Surgical Techniques

Surgical techniques for partial nephrectomy have evolved in conjunction with our improved understanding of kidney tumors. No longer are large, painful incisions and removal of a rib necessary for gaining access to the kidney. Instead, a mini-flank open surgical approach or a robot-assisted laparoscopic approach lead to rapid recovery with less pain and hospital stays of one to two days for most patients.

In addition, postoperative complications of bleeding (<1 percent), urinary leakage from the kidney (<9 percent), and infection are mitigated by early ambulation, excellent postoperative nutrition with protein-rich foods, and limitation of postoperative narcotic use. (9) MSK nurses and physicians are highly experienced in perioperative care and management of any postoperative complications, the vast majority of which can be handled by nonoperative methods.

When patients are elderly, have serious medical comorbidities such as cardiovascular disease, or are already confronting more-aggressive cancers, MSK surgeons usually offer nonoperative treatment in the form of active surveillance in order to avoid the near-term risks of surgery and hospitalization for a tumor in which surgical dividends are usually not appreciated for many years. For patients with these conditions, this approach is not associated with worse kidney cancer–specific survival. Although minimal tumor growth is typically observed in the initial few years of active surveillance, this approach can be changed to operative treatment in the rare event that rapid tumor growth is documented. (10)

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