28 – 30 mai, 2015, Montréal, Québec

PROSTATE CANCER

PLANNING BENEFITS OF MRI FOR EXTERNAL BEAM AND BRACHYTHERAPY

LINE DESROSIERSMARIE-CLAUDE GAUVIN

DISCLOSURE STATEMENT: NO CONFLICT OF INTEREST

May 28 – 30, 2015, Montréal, Québec

I do not have an affiliation, financial or otherwise, with a pharmaceutical company, medical device or communications organization.

I have no conflicts of interest to disclose ( i.e. no industry funding received or other commercial relationships).

I have no financial relationship or advisory role with pharmaceutical or device-making companies, or CME provider.

I will not discuss or describe in my presentation at the meeting the investigational or unlabeled ("off-label") use of a medical device, product, or pharmaceutical that is classified by Health Canada as investigational for the intended use.

LEARNING OBJECTIVES

• Analyse different sequences for MRI

• Understand the role of weighing and how it’s correlated

• Recognize the impact of MRI on treatment plans

• Evaluate the pertinence of MRI in brachytherapy

STATISTICS

• It is estimated that in 2014 in Canada:

• 23 600 Canadian men will be diagnosed with prostate cancer

• 4000 men will die from this disease

• In our department, we treat about 2300 patients per year

• 282 patients are treated for a prostate cancer ~ 13%

• 144 patients received brachy + external treatments ~ 50%

ANATOMY

MRI ADVANTAGES FOR PROSTATE

• Excellent visibility of the prostate gland and capsule

• Superior intraprostatic localisation of dominant lesion

• Better anatomical delineation of the apex, base

• Neurovascular bundles

• External urinary sphincter

• Bladder neck

• Intraprostatic ejaculatory ducts

PROCEDURE RADIOLOGY USES WHEN IMAGING THE PROSTATE …

• NO ejaculations 48 hours before the MRI exam

• 1 Fleet the morning of the exam

• Empty bladder

• Use probe to remove the presence of air in rectum if posterior to the prostate

• Administer Buscopan to stop peristalsis.

• Inject Gadolinium with dynamic sequencing

• Rectal coils (some centers)

A LOOK AT WHAT WE DOCharles-LeMoyne Hospital, radiation oncology department, opened in 2011

PLANNING

• Supine

• Head rest

• Hands on chest holding a ring

• Knee sponge

• Impossible to use vac lock: coil not integrated into the table

• Rectum is empty, bladder is full…

• MRI needs to be similar to the planning CT-scan for better fusion

POSITIONING

• T2 weighed imaging

• axial

• sagital

• T1 weighed imaging

• axial

Multiparametric approach

• Diffusion (DWI)

• axial

• Apparent diffusion coefficient (ADC)

• axial

• Dynamic contrast enhanced (DCE)

• axial

MRI PROTOCOL FOR SEQUENCING PROSTATE

• Prostate and seminal vesicle easily visible

• OARs (bladder, rectum, penile bulb)

• Will help position the other sequences

SAGITTAL T2W IMAGING

• Localize the tumor (hypointense zone)

• Locate the prostate and it’s different zones

• Sequences used by the radiation oncologist for contouring

AXIAL T2W IMAGING

OTHER T2 WEIGHTED

Tzikas, Technol Cancer Res Treat, 2011Henstchel, Strahlenther Onkol, 2011”

AXIAL T1W IMAGING

• See if there is hemorrhaging (hyperintense zones)

• Avoid misdiagnosis of cause of hemorrhaging

• Delay of 6 to 8 weeks between biopsy and MRI

• Allows us to determine the microscopic movements of water within the tissue

• Sequences are very sensitive to artifacts, especially metal

• Combining the T2 image: increase accuracy of detection

• Allows us to make a cartography ADC (next page)

DIFFUSION WEIGHTED IMAGING (DWI)

• Done from the diffusion (DWI)

• Tumors on ADC are weaker than the normal tissues.

• Hypointense region on ADC shows tumor

• Compare and analyze with the other sequences (T2, DCE)

APPARENT DIFFUSION COEFFICIENT (ADC)

DYNAMIC CONTRAST ENHANCE (DCE)

• Allows to measure the vascularity of tissues

• Tumors are characterized by how fast they absorb the contrast

DCE : MRI GRAPHIC UNITS

CHANGES IN PLANIFICATION

URETHROGRAM VISIPAQUE INJECTION

GADOLINIUM INJECTION

BEFORE MRI (CT ONLY)

All patients All patients N/A

SINCE ARRIVAL OF MRI

Patients with MRI containdication

Prostate bed with lymph nodes

• Prostate in place• Postate bed with

positive digital rectal exam

TREATMENTS ARE MORE PRECISEHip replacement

OTHER EXEMPLE OF HIP REMPLACEMENT

CT-Scan MRI Fusion CT-MRI

BETTER PROSTATE LOCALISATION

Discovered after MRI; extra-capsular invasion

• Change of treatment plan

• Hormone therapy for 3 months

• Radiation therapy

TUMOR ADAPTED TREATMENT

Extra-capsular invasion

POST-HORMONAL THERAPY

Discovering a nodule

• Adjust dosimetry

• Boost 125%

• Compromise elsewhere

TUMOR ORIENTED TREATMENT

Arrayeh, Red Journal, 2012Pollack, Red Journal, 2002

DOSIMETRY AND DVH

Ippolito, Am J Clin Oncol, 2012

FORTUNATE DISCOVERIESWhile analyzing the images from the MRI, we found…

CHONDROSARCOMA

T1W T2W

Bladder Cancer

MORE DISCOVERIESAnother bladder cancer!

BRACHYTHERAPY

Use MRI to guide insertion of catheters

• Procedure is done on MRI table

• Image taken

• Insertion of few catheters

• Image to verify position

• Insertion of few more catheters

• Image again

• Etc.

Do MRI post insertion of catheters

• Use ultrasound to guide catheters insertion

• MRI after

• Improve dose optimization

MRI IN BRACHY : 2 CHOICES

What we do

MRI COMPATIBLE APPLICATORS

1 model only$$$$$

Dentist paste!

• Applies easily

• Dries rapidly

• Holds the catheters in place sufficiently

• Can still make adjustments if needed

NEED IMAGINATION… LOTS OF IMAGINATION!

T2 weighed imaging only

• Optimal image of the prostate

• Zoom in on tumoral zone

• Image quality of catheters is sufficient to fuse with ct-scan

• Saves time (pt under anesthesia)

SEQUENCE

Why we do CT-MRI fusionDosimetry cannot use MRI alone :

• Difficulty of seeing catheters

• Therefore reconstruction of the catheters is hard

• Uncertainty when determining catheter tip

Nodules• Boost to 125% respecting OAR

Treatment adjustment

Gaudet, Red Journal, 2010

• Better localization of the prostate

• Better contrast for soft tissue than CT Scan

• Clearer image of prostate anatomy • More precise planning

• Better target control

• Improved treatments for seminal vesicles

CONCLUSION

THANK YOU !

BIBLIOGRAPHY• Société canadienne du cancer[https://www.cancer.ca/fr-ca/cancer-information/cancer-type/prostate/diagnosis/?

region=qc], (Page consultée le 4 mai 2015)

• Favre, Martins. “Place de l’IRM dans le bilan du cancer de la prostate”, dans ID NEWS, 2 juillet 2012, [http://www.idblog.ch/genitourinaire/place-de-lirm-dans-le-bilan-du-cancer-de-la-prostate/], (page consultée le 21 avril 2015)

• Liney, Gary P and Marius A. Moerland. 2014. “Magnetic Resonance Imaging Acquisition Techniques for Radiotherapy Planning”. Seminars in Radiation oncology. Volume 24, p. 160-168.

• Dirix, Piet, Karin, Haustermans and Vincent, Vandecaveye. 2014. “The Value of Magnetic Resonance Imaging for Radiotherapy Planning”. Seminars in Radiation oncology. Volume 24, p. 151-159.

• Tanderup, Kari, Akila N., Viswanathan, Christian, Kirisits and Steven J., Frank. 2014. “Magnetic Resonance Image Guided Brachytherapy”. Seminars in Radiation Oncology . Volume 24, p. 181-191.

• Ménard, Cynthia and Uulke A, van der Heide. 2014. “Introduction: Magnetic Resonance Imaging Comes of Age in Radiation Oncology”. Seminars in Radiation oncoly, Volume 24, number 3, p. 149-150.

Thanks for the help :

• Talar Derashodian, MD

• Maryse Mondat, physicist

• Christina Marcoux, therapist

• Eric Murray, application specialist Siemens