Renal cancer. Contemporary management. Editor John A. Libertino. Springer New York, 2013
Alternative minimally invasive nephron-sparing options
Minimally invasive ablative therapies for renal tumors can be performed percutaneously or laparoscopically and are typically performed with real-time imaging guidance. These techniques are technically less challenging than partial nephrectomy as there is no need for hilar clamping, aIncluded patients had biopsy-proven renal cell carcinoma prior to treatment collecting system reconstruction, renorrhaphy, or adjacent organ dissection. Ablative therapy is typically limited to clinical T1 tumors and patients with increased surgical risks. The majority of patients undergo renal biopsy prior to ablative procedures to confirm presence of malignancy. It is the recommendation of the American Urological Association that all patients undergo percutaneous renal biopsy prior to ablative procedures. The two most commonly studied and utilized methods are cryoablation and radiofrequency ablation (RFA). Cryoablation causes cellular damage from both the freezing temperatures induced by iceball formation from rapid expansion of high-pressure argon gas and subsequent reperfusion injury during thawing. RFA utilizes alternating current transmitted to cells via electrodes. The energy causes agitation resulting in tissue heating to temperatures over 60°C. At this temperature, irreversible cell damage and necrosis occurs. The choice of approach, open, laparoscopic, or percutaneous, depends on tumor location and its proximity to the bowel, adjacent organs, and the great vessels. Complication rates and oncologic outcomes between percutaneous and laparoscopic approaches appear to be equivalent [75–77]. In patients with recurrent disease, ablative therapy did not preclude radical nephrectomy [74, 78].
Таблица 14.2. Сообщенные онкологические исходы минимально инвазивных нефрон-сохраняющих процедур для T1 опухолей почек
A number of studies have compared MIPN (LPN or RALPN) to laparoscopic cryoablation (LCA) [75, 79–82]. These studies have demonstrated similar short-term oncologic outcomes; however, longer-term data is needed. Aron et al.  present 80 patients who underwent LCA with a median follow-up of 93 months (range 60–132). In patients with biopsy-proven renal cell carcinoma, 5and 10-year disease-specific and recurrence-free survival was 92% and 81% and 83% and 78%, respectively. Midterm oncologic outcomes of radiofrequency ablation for SRMs are published [74, 83, 84]. Tracy et al. report 208 patients undergoing either laparoscopic or percutaneous radiofrequency ablation with a mean follow-up of 27 months. There were nine local recurrences with 5-year recurrence-free survival of 93%. The overall 5-year survival was 85%. These outcomes are inferior to published disease-specific survival data for extirpative therapy for T1a tumors. A meta-analysis comparing cryoablation to RFA suggests that patients undergoing RFA have higher local tumor progression, but no direct comparisons of the two modalities exist. Таблица 14.2 provides a comparison of oncologic outcomes of minimally invasive nephron-sparing procedures for T1 tumors reported in the literature. The largest series with the longest follow-up were selected. Thoughtful consideration is necessary when comparing MIPN and ablative therapies as the indications for each vary and the patient populations are often significantly different with the MIPN population being younger and healthier. At the present time, minimally invasive ablative procedures should be reserved for patients requesting treatment, but are high-risk surgical candidates.
New treatment modalities such as high-intensity focused ultrasound (HIFU) and microwave therapy remain investigational. An international group has reported their experience with extracorporeal and laparoscopic HIFU demonstrating its feasibility and safety [9, 86]. Castle et al. reviewed their experience with ten patients undergoing microwave therapy, which showed high postoperative complication rate (40%) and high recurrence rate (38%) for the cohort. Further trials and longer-term follow-up are needed to demonstrate the oncologic safety of these novel techniques.