Nephron-Sparing Surgery — Strategies for Partial Nephrectomy in Renal Cell Carcinoma

Prognostic value of intraoperative measurements of renal tissue oxygenation and microcirculation on renal function in partial nephrectomy

BACKGROUND

Partial nephrectomy (PNx) can be associated with macrocirculatory and microcirculatory alterations, ultimately leading to acute kidney injury (AKI). Measuring kidney tissue oxygenation (μHbO2) and microcirculation during open PNx might be feasible to early detect these alterations and prevent postoperative AKI.

METHODS

μHbO2 and microcirculation were measured in 45 patients undergoing PNx by reflectance spectrophotometry and laser Doppler flowmetry (O2C™, Lea, Germany), related to ischemia time and tumour size. Pre- and postoperative creatinine levels were determined.

RESULTS

μHbO2 was lower after reperfusion than before clamping (72 vs. 75%), while microcirculation and regional haemoglobin did not differ. Ischemia time was 15.7 min on average. μHbO2 was higher without ischemia (80 vs. 70%, p = 0.109) and in T1a- than T1b-tumours, independent of ischemia time and reperfusion. The renal collecting system (RCS) was opened in 19/45 patients with μHbO2 of 68% after reperfusion compared to 74% with intact RCS. Postoperative complications occurred in 6/45 patients (13%). μHbO2 was 68% before clamping vs. 75% without complications. Serum creatinine of patients with T1b was higher compared to T1a (103 vs. 87 µmol/L). Patients with larger tumours had higher postoperative creatinine levels (173 vs. 124 µmol/L; p = 0.052).

CONCLUSION

We showed for the first time that the method is feasible to monitor renal tissue oxygenation at the level of microcirculation non-invasively and reproducibly during PNx. Tumour size seems to have a decisive influence on oxygenation and postoperative renal function. Our results imply that postoperative complications may be predicted by low intraoperative renal oxygenation and microcirculatory flow measurements.

[Indications for nephron-sparing surgery. Analysis over a 13-year period in the context of changing guidelines]

BACKGROUND

The indications for nephron-sparing surgery have been considerably extended by guideline recommendations in recent years. It remains unclear whether clinical practice still reflects these new guidelines.

OBJECTIVE

In this retrospective, monocentric analysis at a tertiary referral center the indications for partial nephrectomy over a 13-year period were evaluated.

METHODS

In a retrospective database analysis all cases of surgically treated renal masses from 2001 to 2013 were evaluated. Besides demographic, tumor-specific and perioperative variables the development of the surgical technique depending on the tumor stage was evaluated.

RESULTS AND DISCUSSION

The proportion of nephron-sparing surgery cases increased from below 20 % in 2001 to 35 % in 2013 in the entire cohort. For stage T1a tumors, partial nephrectomy increased from approximately 50 % to over 90 % and for T1b tumors it rose from 10 % to 50 %. Logistic regression revealed stage 1 tumors to be predictive of partial nephrectomy over the complete evaluation period. Extending the indications for partial nephrectomy even to higher stages is under discussion but not yet supported by data from prospective, controlled studies.

[Nephron sparing surgery in renal cell carcinoma: our experience of a 20-year clinical practice]

OBJECTIVES

Nephron sparing surgery (NSS) is now considered the standard of care in the treatment of renal cell carcinoma (RCC) in stage T1. We retrospectively evaluated our results related to the use of NSS in over twenty years of clinical practice.

METHODS

We reviewed our database relating to the use of NSS in the last twenty years of clinical practice, from 1988 to July 2012, in 549 patients. The pre- and post-operative parameters recorded are the evaluation of the site and size of the renal lesion obtained from radiological investigations, the need for clamping the renal pedicle, open or laparoscopic surgical approach, blood loss, histology and intra- and postoperative complications. We also evaluated the parameters related to renal function before and after surgery.

RESULTS

The mean follow-up was 95 months (7.6 years). The average diameter of the lesion at CT abdomen was 4.8 cm (1-8 cm). The warm ischemia was required in 317 patients, cold in 18 patients, no need for ischemia in 214 patients. The total duration of surgery was 122.56 ± 52.76 min. 15 procedures were performed laparoscopically. Ischemia time: 3'-25'; bleeding: 50-1000 cc. The lesion was benign in 115 of the 549 patients enrolled; it was a RCC in the remaining cases except for three, which were papillary carcinomas. At 5 years, the cancer free survival rate was 97.5%.

CONCLUSIONS

Our data show that the implementation of NSS offers long-term benefits in terms of functional results and a good cancer control.

Application of contrast-enhanced ultrasonography after radiofrequency ablation for renal cell carcinoma: is it sufficient for assessment of therapeutic response?

PURPOSE

To assess the efficacy of contrast-enhanced ultrasonography (CEUS) with Sonovue in the evaluation of therapeutic response to radiofrequency ablation (RFA) of renal cell carcinoma (RCC).

MATERIALS AND METHODS

In a recent 3 years, 63 patients (mean age, 60 years; range 26-81 years) with 64 RCCs were treated by RFA. The lesions had a diameter between 1.8 and 9.8 cm (average diameter, 3.1 cm). The indications for RFA treatment included chronic renal insufficiency (n = 10), presence of solitary kidney (n =3), bilateral renal carcinoma (BRCC) (n =2), advanced age (n =12), significant medical comorbidity (n =29) or refusal of conventional therapy (n =7). Tumors were treated by laparoscopy-assisted (n =41), open surgical (n =18) or percutaneous US guidance (n =4). Follow-up CEUS and contrast-enhanced CT were performed 1 month after treatment to assess the necrotic area. Technical success was defined as elimination of areas that enhanced at imaging within the entire tumor.

RESULTS

On the 1-month CEUS and CT imaging after RFA, 62 of 64 tumors (96.9%) were successfully ablated with one session, and residual tumors were found in two RCCs. One of the two tumors was subjected to additional RFA treatment. We could not obtain a complete ablation in the other tumor of a patient with solitary kidney. The diagnostic concordance between the CEUS and 1-month follow-up CT was 100%. Sixty-one patients survived in the follow-up phase which ranged from 2 to 34 months. One patient with solitary kidney died of systemic disease progression and one patient was lost to follow-up. Of the 61 tumors without residual on both CT and CEUS after RFA, four had suspicious findings of recurrence on follow-up CEUS, and two of them were confirmed by subsequent CT examination. With CT as the reference imaging procedure in the assessment of renal tumor ablation, the sensitivity, specificity, positive predictive value, and negative predictive value of CEUS for detecting recurrence during follow-up were 100%, 96.6%, 50%, and 100%.

CONCLUSION

Despite its limitation of false-positive value, CEUS is potentially effective in assessing the therapeutic response to RFA of RCC.