31st July 2010

Radiation therapy in Wilms Tumor

Dr. Lokesh Viswanath M.DProfessor, Department of Radiation

OncologyKidwai Memorial Institute of Oncology

Radiation Therapy Wilms Tumors - high sensitivity – ionizing

radiation

1940`s (all stages) 5yr survival Surgery alone : 15-20% Post OP RT : 47%

1970`s CT - Distant relapses

typically - large T size at presentation propensity for metastasis (hematogenous)

Roles of Radiotherapy Historical

Definitive radiation therapy Contemporary

Preoperative Radiation Flank Whole Abdomen

Postoperative Radiation Flank Whole Abdomen Lung bath

Treatment of recurrence Abdomen (localized abdominal recurrence)

Treatment of metastasis Lung Brain Bone Liver Lymph nodes

Indications Multimodality, stage and risk adapted

approach is the standard of care Radiation therapy is now a days indicated in

a selected few to eliminate the risk of local recurrence

RT Management varies according to: Age of patient (avoided in < 6 months infants /

<2yrs FH) Preoperative extent on imaging Operative stage Post operative histology

RT - Indications : Post OP RT

WT - Favourable Histology Stage III:

residual T Gross/Micro +ve Margin Local Infiltration Vital Structures

Abd/Pelv -Ly N + peritoneal surface

Penetration Tumour implants T Spillage (pre / intro OP)

Bx – trucut, Bx, FNAC T removed in Pieces : eg - extn adrenal

, T thrombus in renal vein Standard Risk FH WT without LOH at

1p & 16q Higher Risk FH with LOH at 1p & 16q

Stage IV Rapid responders of lung metastasis at

week 6 on DD4A (Possibility of no-RT to rapid complete

responders on CT scan) Slow responders (lungs) & non-

pulmonary metastasis

WT Unfavourable Histology Anaplasia

Stage I – diffuse Stage II-IV – diffuse Stage I-IV - Focal

Clear cell CCSK Stage I-III Stage IV

Rhabdoid RTK Stage I -IV

RT Technique

Timing of RT : not later than 9 days after surgery (max 14 days)

Delay of >10dys – significantly higher abdominal relapse rate , particularly UH.

RT Machines

Telecobalt Linear Accelerator

RT Techniques Flank RT Whole Abdomen RT (WAI):

Indicated – diffuse tumor spillage - Pre-OP / Intra OP Tumor Rupture Peritoneal T seeding Ascites +ve Cytology

Whole Lung RT Localized foci of lung disease persisting 2 weeks

after 12 Gy can be excised or given additional 7.5 Gy Treat both lungs regardless of the number or

location of visible metastases Patients with CT only pulmonary mets – at the

discretion of the treating institution

General Principles : RT planning Pt position : Supine Immobilization: Vacuum Cushion Sedation / Anesthesia during RT / Simulation Simulation:

Simulator – X –Ray + IVP (to Exclude Opposite kidney) CT Simulation

Ensure – Anesthesia & Patient monitoring equipments in the RT Bunker

Opposed AP:PA fields Field Shaping : 3DCRT / Contouring Shielding opposite kidney & selected normal

structures Complete Vertebrae to be included in the RT field

RT DoseStage III FH FLANK RT :

10.8Gy, 180cGy/fx

Stage I-III Focal anaplasia

Diffuse anaplasia

CCSKStage III Diffuse anaplasia

FLANK RT : 19.8Gy (Infants -10.8Gy), 180cGy/fxStage I-III RTK

Whole Abdomen RT

FH 10Gy, 150cGy/Fx

Residual Boost

+ 10GyRenal Shielding / Limit the dose to remaining kidney <14.4Gy

Lung (mets.) FH / UH 12Gy WLI in 8#

Liver (mets.) 19.8Gy WLivI in 11#

Brain (mets.) 36.6Gy WB in 17#Or 21.6Gy WB + 10.8Gy IMRT /SRST Boost

Unresected Lymph nodes

19.8Gy in 11#

Bone (mets.) 25.2 Gy in 14#

Flank Radiation Treatment Portal design :

Should encompass the tumor bed and the site of the excised kidney

2-3 cm margins should be given circumferentially

3D Plans: PreOP CT/MRI – CTV : kidney + Tumor with 1cms Margin

Field sizes ~ 10 x 10 / 12 x 12 cms Beam energy : 4-6 MV

Treatment Fields - Flank

Whole Abdomen Radiation Indicated in few patients now a days energy - 4-6 MV photons Shielding :

Opposite kidney : Posterior 5 HVL shield Acetabulum and femoral heads – both AP-PA shields

Superior border : dome of diaphragm (nipples) Inferior border : inferior border of the

obturator foramen( pubis symphysis ) Lateral border : to the lateral peritoneal

reflection

Lung Irradiation Superior border : 3cm above the

middle 1/3 rd of clavicle Inferior border : ( below the

costophrenic angles) Below the xiphisternum / level of L1 (transpyloric plane)

Lateral borders : Lateral border of areola of nipple

Shielding humeral head larynx

bilateral Wilms’

Dose to more than 1/3 of the contralateral kidney or residual kidney should not exceed 14.4 Gy

Inoperable Bilateral WT- role of Cyber Knife, Tomotherapy, Rapid Arc, True Beam, IMRT to be conscidered . PET based planning.

Long-term results of NWTS-3 and -4

Results – 4yrs – FH (NWTS 5)Stage RFS OS EFS

I 92% 98%

II 83% 92%

III 85.3% 93.9%

IV 74.6% Lung Mets,Pulm RT

Results UH (NWTS 5) Diffuse Anaplasia 2 y

EFS Stage I 64.3 % Stage II 79.5% Stage III 62.7% Stage IV 33.6%

CCSK Stage I –IV 4y RFS

77.6% 6/9 Stage IV patients

relapsed

Rhabdoid Tumors Stage I 50% Stage II 33.3% Stage III 33.3% Stage IV 21.4 % Stage V 0%

Conclusion WT at presentation is a large tumor and

has a high propensity for distant metastasis

However the prognosis is excellent with modern day Multimodality Management

Surgery with chemotherapy is the mainstay of treatment

Radiation therapy given judiciously can reduce recurrences and improve QOL

Thank You