PET/CT: Is there a role in RT planning? C. Messa University of - - PowerPoint PPT Presentation

PET/CT: Is there a role in RT planning?

• C. Messa

University of Milano Bicocca, IBFM-CNR, Inst H S Raffaele Milano, H San Gerardo, Monza

ICARO, Vienna 2009

PET/CT in RTplanning

• Decide for RT ‘curative’ treatment
• Decide for RT treatment type
• Assess response and prognosis

Decide for RT treatment: patients selection

PET/CT with 18F-FDG (11C-Choline for prostate cancer)

• STAGING (NSCLC, H&N, OESOPHAGEAL,

CERVIX, LYMPHOMA)

• RE STAGING (ALL ABOVE PLUS PROSTATE

CANCER)

M.A. 73 yrs HSR - Milano 16/9/05 18F-FDG CT PET-CT

Left lung cancer candidate to RT

HSR Milan

Local recurrence LN M [ [11

11C]Choline

C]Choline-

• PET/CT: total body study

PET/CT: total body study

Author Tumor Site Sens Spec

Arulampalam (2004) Colon Liver 100% 91% Gallowitsch (2004) Breast Various 97% 82% Hellwig (2001) Lung Adr gland 96% 99% Pieterman (2000) Lung Various 82% 93% Bury (1998) Lung Bone 92% 98%

[18F]FDG-PET M staging Unknown Unknown mts mts identified identified by by PET : PET : up up to to 20 20% of % of cases cases * *

* Lardinois D et al. NEJM 2003

Decide RT treatment type

• The PET-based GTV

(‘Biological Target Volume’)

• The boost

PET/CT-based GTV ( GTV )

C.G., 53 aa Lung Cancer 18-10-02 HSR Milano

Atelectasia + Tumor Effusion

CT PET/CT CT-based TT PET/CT-based TT

PET/CT-based BTV ( GTV )

TOMOTHERAPY TREATMENT PLAN

HSR Milano

FDG-PET : GTV/PTV variations

20%-25% 2 Cervix H&N Lung SITE 17%-58% 4 20%-70% 13 Variation N° studies

Grosu AL . Strah Onk 2005;181:483-499

How to contour FDG avid lesions

90% 70% 60% 50% 45%

Visual, SUV-based,Thresholding, Background cut-off, source/background algorithms

McManus et al, radioth and oncol, 91:85-94, 2009

Organ and Lesion Motion

Static Target Moving Target

Standard planning volume ( 30.8 cc ) 4D PET/CT planning volume (12.2 cc) 60%

heart marrow

• esophagus

Left lung Right lung

Dose escalation on GTV (PET+)

FDG +

SIB approach Dose escalated to 69 Gy Acute tox comparable to a similar group of patients without dose escalation

• n GTV

FDG PET volume

Assess treatment response

• Prediction of response
• Monitoring therapy
• Assess response after therapy

• Membrane function

[11C]Choline

• Amino acids metabolism

[18F]FET / [11C]MET

• Proliferation

[18F]FLT [18F]FMISO

• Hypoxia

[18F]FAZA [64Cu]ATSM

• Apoptosis

[18F]Annexin V

• Angiogenesis

[18F]RGD peptide

Alternative PET oncological tracers

⎨

Cervical Cancer : : Survival vs. 60Cu-ATSM Uptake

.2 .4 .6 .8 1

Progression-Free Survival

5 10 15 20 25

Time after Therapy (Months)

T/M < 3.5 T/M > 3.5 P = 0.0005 .2 .4 .6 .8 1

Overall Overall Survival

5 10 15 20 25

Time after Therapy (Months)

T/M < 3.5 T/M > 3.5 P = 0.015

Dehdashti et al., Int J Radiat Oncol Biol Phys, 2003; 55:1233

PET/CT during RT (70 Gy in 35 days)

Basal T = 0 SUVmax : 15 50 Gy T= 25 gg ΔSUV: - 49% post RT T = 90 gg ΔSUV: - 61%

HSR Milano

PET/TC BASAL, 25 gen 2006 PET/TC AFTER 3 mo. End of RT 11-5-2006 MMG, 48 yrs, breast ca (T2,N2) mastectomy RT CT 2002, lombalgia in 2005

After 4 months

post-TT Pre-TT

67.2 Gy in 28 fractions Case 2: Common iliac nodes

Pre-TT

Conclusion:

PET/CT in RT: Is there a role?

• Patients selection: indicated also by PET studies of

staging - restaging accuracies

• PET-based GTV definition (eg Lung and H§N

cancer): significant changes in RT treatment (Dose, field design), but no data on pts outcome

• Predict prognosis (FDG + new radiopharmaceuticals)
• Response Assessment : indicated at the end (3 mo);
• ther tracers (FLT?); early assessment?