[Percutaneous renal ablation: Pre-, per-, post-interventional evaluation modalities and adapted management]

Role of MRI at 1- and 3-Month Follow-up in Predicting the Likelihood of Tumor Recurrence Following Percutaneous Cryoablation of Renal Tumors

PURPOSE

To evaluate whether ablation volume difference relatively to tumoral volume, minimal distance between ablation area and necrotic tumor, or apparent diffusion coefficient (ADC) within the ablation area, measured on 1- and 3-month follow-up MRI following cryoablation of renal tumors, are associated with tumor recurrence.

MATERIALS AND METHODS

136 renal tumors were retrospectively identified. Patients, tumor characteristics and follow-up MRI (1-, 3-, 6-month, and thereafter annually) were collected. Uni- and multivariate analyses were performed to assess the association between the investigated parameters and tumor recurrence.

RESULTS

Over the follow-up period (27.7 ± 21.9 months), 13 recurrences were identified at 20.5 ± 19.4 months. At 1- and 3-month, the mean volume difference between the ablation zone and the tumor volume were + 577.5 ± 511.3% vs + 251.4 ± 209.8% (p = 0.003), and + 268.8 ± 291.1% vs + 103.8 ± 94.6% (p = 0.023) in patients without and with tumor recurrence, respectively. At 1- and 3-month, the minimum distance between the necrotic tumor and the edge of the ablation area was 3.4 ± 2.5 vs 1.8 ± 1.9 mm (p = 0.019), and 2.4 ± 2.3 vs 1.4 ± 1.8 mm (p = 0.13) in patients without and with tumor recurrence, respectively. Analysis of ADC values was not associated with tumor recurrence. After performing the multivariate analysis, only volume difference of the ablation area compared to tumor volume was associated with absence of tumor recurrence at 1- (OR = 14.1; p = 0.001) and 3-month (OR = 8.2; p = 0.01).

CONCLUSIONS

Evaluation of volume difference between the ablation area and tumor volume on early (≤ 3 months) MRI follow-up identifies patients at risk of tumor recurrence.

Repeat ablative therapy in hereditary or multifocal renal cancer: Functional and oncological outcomes

OBJECTIVES

To report managing renal tumors in patients at greater risk of repeated interventions (genetic predisposition, multifocal tumors) with thermoablative treatments (AT). A known significant challenge in these patients is the balance between nephron preservation and oncologic outcome.

MATERIAL AND METHODS

This retrospective, single-center study was based on data from patients treated with one or more AT for hereditary or multifocal renal tumors between 2007 and 2017. All medical records were systematically reviewed, and 10 patients meeting inclusion criteria were selected. Six patients had confirmed von Hippel-Lindau disease, 1 Bird-Hogg-Dubé syndrome, 1 chromosome 3 translocation, and 2 had a presumed genetic predisposition.

RESULTS

Median age at cancer diagnosis was 39.5 years (±8.9). Fifty-seven tumors, including 41 de novo tumors that appeared during follow-up, were treated with 32 AT sessions (cryotherapy or radiofrequency) with an average tumor size of 13.5 mm (±9) and a median RENAL score of 6 [5; 7]. One patient underwent concomitant partial nephrectomy for a 55 mm lesion which was close to the bowel. Treatment was unsuccessful in 2 cases, subsequently managed successfully by retreatment with AT. Median delay of appearance of de novo tumor after the first AT was 18 months [6 ; 24]. One patient had metastatic progression. Overall and cancer specific survival was 90% and 100%, respectively, with a mean follow-up of 7.5 years (±4.9). The mean decrease in Chronic Kidney Disease - Epidemiological Collaboration equation-estimated glomerular filtration rate at the end of follow-up was 5.5 ml/min/1.73 m² (±24).

CONCLUSION

This study suggests that AT allows to meet the oncological objectives whilst preserving renal function in patients with renal cancer at greater risk of repeated treatments.