Ablative therapies in the treatment of small renal tumors: How far from standard of care?

Long term follow-up results of ablation treatment for patients with small renal mass

OBJECTIVE

The aim of this study is to evaluate the outcome of ablation therapy in our clinic for the treatment of patients with a small renal mass Materials and Methods: We retrospectively evaluated the technic and follow-up data of 30 patients with 36 tumours who underwent Radiofrequency Ablation (RFA) and Microwave Ablation (MWA) in our clinic. Demographic data, ablation type, tumour characteristics, peroperative and postoperative complications and treatment success of the patients were evaluated.

RESULTS

A total of 36 tumours who underwent ablation treatments, 23 were treated with RFA, 13 with MWA. The mean tumour size was 28.9 ± 6.92 mm in RFA and 29.3 ± 7.70 mm in MWA. The mean follow-up period was 49.6 ± 24.7 months in patients with RFA and mean follow-up was 16 ± 8.05 months in MWA treatments. The overall success in MWA administration was calculated as 76.9%, while the overall success in RFA was 80%.

CONCLUSION

Long-term oncologic efficacy of RFA appears to be successful in the treatment of T1a renal carcinomas. Further studies can be conducted to elucidate the influence of MWA on long-term oncological outcomes.

Renal preservation therapy for renal cell carcinoma

Renal preservation therapy has been a promising concept for the treatment of localized renal cell carcinoma (RCC) for 20 years. Nowadays partial nephrectomy (PN) is well accepted to treat the localized RCC and the oncological control is proved to be the same as the radical nephrectomy (RN). Under the result of well oncological control, minimal invasive method gains more popularity than the open PN, like laparoscopic partial nephrectomy (LPN) and robot assisted laparoscopic partial nephrectomy (RPN). On the other hand, thermoablative therapy and cryoablation also play an important role in the renal preservation therapy to improve the patient procedural tolerance. Novel modalities, but limited to small number of patients, include high-intensity ultrasound (HIFU), radiosurgery, microwave therapy (MWT), laser interstitial thermal therapy (LITT), and pulsed cavitational ultrasound (PCU). Although initial results are encouraging, their real clinical roles are still under evaluation. On the other hand, active surveillance (AS) has also been advocated by some for patients who are unfit for surgery. It is reasonable to choose the best therapeutic method among varieties of treatment modalities according to patients' age, physical status, and financial aid to maximize the treatment effect among cancer control, patient morbidity, and preservation of renal function.

Initial experience using microwave ablation therapy for renal tumor treatment: 18-month follow-up

OBJECTIVES

To assess efficacy and morbidity of microwave ablation (MWA) for small renal tumors in an initial cohort of patients. MWA is a recently introduced thermal needle ablation treatment modality with theoretical advantages compared with radiofrequency ablation, such as greater intratumoral temperatures, lack of a grounding pad, and superior convection profile. However, experience has been limited in the human kidney.

METHODS

Ten patients with a single, solid-enhancing renal tumor from June 2008 to November 2008 received laparoscopic or computed tomography-guided percutaneous MWA at a tertiary referral center with ≥14 months of follow-up. MWA was performed using the Valleylab Evident, 915-MHz MWA system at 45 W with intraoperative biopsy before ablation, and peripheral fiberoptic thermometry to determine the treatment endpoints. The patients were followed up with contrast-enhanced computed tomography at 1 month, 6 months to 1 year, and annually to monitor for tumor recurrence.

RESULTS

The follow-up duration for the 6 male and 4 female patients (mean tumor size 3.65 cm, range 2.0-5.5; mean age 69.8 years) was 17.9 months. The recurrence rate, defined by persistent enhancement, was 38% (3 of 8). The intraoperative and postoperative complication rate was 20% and 40%, respectively.

CONCLUSIONS

MWA resulted in poor oncologic outcomes with a significant complication rate at an intermediate level of follow-up. However, MWA has promising theoretical advantages and should not be discarded. Additional studies should be considered to better understand the microwave-tissue interaction and treatment endpoints for different size renal masses before widespread use.

The ongoing history of thermal therapy for cancer

Through 5,000 years of practice, physicians, surgeons, clergy, or lay people have used thermal therapy to treat mass lesions now known as cancer. The methods have changed dramatically over this time span and certainly the techniques have improved the efficacy and safety. Hyperthermia used in combination with chemotherapy or ionizing radiation continues to improve outcomes. The authors briefly describe the historical role of hyperthermia in cancer care as well as modern expectations based on technological advancements. In particular, the article focuses on the role of hyperthermia for cancers that do not have other, more effective treatments.

Radiofrequency ablation: a minimally invasive approach in kidney tumor management

The management and diagnosis of renal tumors have changed significantly over the last decade. Due to advances in imaging techniques, more than 50% of kidney tumors are discovered incidentally and many of them represent an early stage lesion. This has stimulated the development of nephron-sparing surgery and of the minimally invasive treatment options including ablative techniques, i.e., radiofrequency ablation (RFA) and cryoablation. The objective of the minimally invasive approach is to preserve the renal function and to lower the perioperative morbidity. RFA involves inducing the coagulative necrosis of tumor tissue. Being probably one of the least invasive procedures in kidney tumor management, RFA may be performed percutaneously under ultrasound (US), computed tomography (CT) or magnetic resonance (MR) guidance. Most of the studies show that the RFA procedure is efficient, safe and has a low complication rate. Due to the still limited data on the oncological outcome of RFA, the indication for this intervention remains limited to selected patients with small organ-confined renal tumors and contraindication to surgery or who have a solitary kidney. The aim of our study is to review the literature on RFA of kidney tumors.