Interventional Radiology in the renal tumor :

Biopsy and RF

P. Taourel (Montpellier)

• Diagnosis • Treatment

Small tumors : adenocarcinoma ?, oncocytoma? AML without fat Invasive tumor

= Cancer

Fat =

Angiomyolipoma

Solid Tumors

Characterized by imaging Diagnosis difficulties

Staging

Be careful with US in angiomyolipoma

•  Characteristics : –  Hyperechoic ≥ : sinusal fat –  Homogeneous

•  Be careful –  Calcification –  Hypoechoic rim

•  30% of cancers are hyperechoic

•  US can not characterize an angiomyolipoma : CT

AML

Cancer

AML diagnosis = fat

•  < -20 UH •  Easy

AML typique (-60 UH)

•  Tiny content of fat may be challenging

AML à faible contingent adipeux

CT identification of the fat

•  Thin slice

•  Adapted ROI

•  ≤ - 20 UH

•  No IV contrast

Temps néphrographique

Sans injection, coupes fines

How to recognize AML without fat

•  5 à 15% •  Orientation criteria

–  STB –  Multiple AML in a young woman –  US –  Spontaneously hyperdense (=

muscle) + hypervascular –  Présence de vaisseaux anévrismaux

•  MRI ? •  Biopsy +++

Biopsy : AML)

Invasive tumor =

Cancer

Fat =

Angiomyolipoma

Solid Tumors

Characterized by imaging Diagnosis difficulties

Staging

Small tumor without fat : adk, aml without fat, oncocytoma

CT

•  Fast enhancement (cortical phase)

•  Washout •  Scarr hypodense :

central + small + starr

Temps cortical (artériel)

Temps néphrographique

Small oncocytoma < 4 cm

•  Characterization : difficult •  Enhancement :

homogeneous •  Scarr : missing (10%)

Small homogeneous oncocytoma

•  Solid tumor in multicystic kidney

No iv cortical 35 sec tubular 80 sec

Biopsy= ONCOCYTOMA

Solid renal tumor without fat on CT ≤ 4 cms must be biopsied

•  Only one tumor must be characterized : AML •  Incidence of benign lesion : 20% ( if ≤ 2 cms) •  Biopsy easy to perform

CT value to characterize tumor

•  Consecutive study of 99 solid renal tumor without fat

•  18 G biopsy with FU •  CT accuracy

– B (25%) / M (75%)

Millet AJR 2011

CT findings

•  Morphologic criteria –  siza –  Ball versus bean –  Segmental inversion –  scarr –  Interface with the parenchyma

•  Critères cinétiques –  Enhancement intensity –  Time-course pattern

Metanephric adenoma

Ischemia

ONCOCYTOMA

ADK

Lymphoma

Wegener

oncocytoma

adk

Inverted segment ADK oncocytoma

A weak significant finding of benignancy : progressive enhancement

•  Sen = 60% •  Spe = 73% •  PPV = 43% (prevalence of benignancy) •  NPV = 84%

– AJR 2011 Millet et al

Tubulo-papillar adk

Biopy of small renal tumor is mandatory

•  Benign versus malignant : impact ++++

•  Type of adk : impact ?

•  Grade : impact + – Partial surgery – Temperature ablation – Active FU

•  187 solid tumors ≤ 4cms •  145 Malignant •  132 renal cancers,

–  61 surgery –  36 RF –  35 FU

Millet J Urol 2012

Table 1 Biopsy-surgery correlation for the histologic subtype

Surgical subtype

Biopsy subtype

Clear cell Chromophobe Tubulopapillary Unclassified

Clear cell 55 13 5 1

Chromophobe

Tubulopapillary

Unclassified

Table 2 Biopsy-surgery correlation for the Fuhrman grade

Surgical grade

Biopsy grade

G1 G2 G3 G4

G1 7 11 33 2 2 6

G2

G3

G4

To conclude on diagnosis : the biopsy of renal tumor is

•  Easy (LD if lesion in upper part of the kidney)

•  Accurate •  Useful (25% of benign

lesion) •  Mandatory (no CT

characteriation) •  Impact on treatment of adk

(weak underestimation of the grade)

• Diagnosis

•  Treatment

Radiofrequency of renal tumors

• Why ? (overdiagnosis and overtreatment ?)

• How ? • What results ? • When ?

→ Ionic agitation → Friction with heat in the tissues → Thermal damage with heating

→ Nécrosis of coagulation (50 – 100 ° ) →  ≥ 100 ° carbonization with non

efficiency of the treatment

Radiographics 2001

What evaluation before ? •  Proof of malignancy (25% : B) •  Size of the lesion : < 3cm, 3-5 cm •  Localization de la lésion :

ball vs bean central or not

•  Contact = pleura, bowel, ureter

What technique ?

•  decubitus •  Ureteral stent •  Hydrodissection •  Displacement of the mass by the electrode

What FU ? •  2 questions :

– Efficiency – Recurrence

•  Sémiologie uniqvoque –  fat stranding – Rim finding (no significance)

•  Enhancement : residu or recurrence –  nodules or croissants (triphasic CT)

M 2

What FU ? •  2 questions :

– Efficiency – Recurrence

•  Sémiologie uniqvoque –  fat stranding – Rim finding (no significance)

•  Enhancement : residu or recurrence – Cortico-medullary phase

M 2

M 8

FU : 2m, 6m, 1y, then every y

What results : ?

•  Efficiency : 80 – 90 % •  Predictive factors :

–  exophytic (oven effect) – < 3 cm

What results ?

Excise,ablate or observe : the small renal mass dilemna J Urol 2008

What results : a metaanalaysis

age size

PN 5037 (77,8 %) 60 3,40 Cryoablation 496 (7,7 %) 65,7 2,56 RF 607 (9,4 %) 67,2 2,69 FU 331 (5,1 %) 68,9 3,04

J Urol 2008

What results : a meta analysis

FU (month) Dgc LR M pathol : K

PN 54 87 % 2,6 % 5,6 % Cryoablation 18 76 % 4,6 % 1,2 % RF 16 88 % 11,7 % 2,3 % FU 33 91 % 0,9 %

J Urol 2008

Ablation of renal tumor : (cryoablation or RF)

•  Tm < 4 cm •  exophytic or parenchymateous •  Age > 70 ans •  cobormidity or failure renal factor risk

or •  Recurrence after partial nephrectomy

or •  VHL syndroma