Radiation Therapy in Prostate Cancer Current Status and New Advances

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1 Radiation Therapy in Prostate Cancer Current Status and New Advances Arno J. Mundt MD Professor and Chairman Dept Radiation Oncology Moores Cancer Center UCSD

2 Radiation Therapy Wilhelm Roentgen ( ) Discovers X-rays in 1895 Use of high energy x-rays to treat cancer Long history in the treatment of cancer 1 st patient in 1896 within 2 months of the discovery of X-rays

3 Radiation Modalities External Beam Involves the use of photons and electrons Brachytherapy Close therapy Radioactive sources placed within the prostate

4 Radiation Therapy and Prostate Cancer First used to treat prostate cancer in 1909 Radioactive Radium inserted into the urethra Machines of the day could not produce sufficiently penetrating beams London (1920)

5 Radiation Therapy and Prostate Cancer Recognized that a superior approach would be to insert radium needles directly into the prostate More of the prostate could be treated with less damage to the urethra Prostate Brachytherapy Urology Textbook (1926)

6 Early Prostate Brachytherapy Prostate Implant (1917)

7 Radiation Therapy in Prostate Cancer Enthusiasm for brachytherapy and RT in general decreased after WWII Many patients were not cured Mainstay of treatment became surgery Excitement also surrounded discovery of the hormonal therapy

8 Radiation Therapy in Prostate Cancer Interest returned in the 1960s Development of megavoltage (high energy) machines Highly penetrating beams which treat the prostate without excessive skin toxicity Malcolm Bagshaw Stanford University Demonstrated that prostate cancer is curable with external beam (megavoltage) RT Stanford University (1962)

9 Radiation Therapy in Prostate Cancer Brachytherapy revived in late 1960 s Radioactive seeds implanted at surgery Long-term results were not good Most likely due to poor distribution of the seeds throughout the prostate Parts of the tumor were not treated adequately

10 Prostate Brachytherapy Newer techniques allow seeds to be better distributed throughout the prostate Free Hand Technique Ultrasound Guided Interest decreased today with permanent seed implants due to urinary side effects and advances in external beam RT

11 High Dose Rate (HDR) Brachytherapy More sophisticated approach is to use temporary HDR implants Conforms dose better to the prostate reducing dose to normal tissues HDR Program planned at UCSD Andy Grove Chairman Intel

12 External Beam Treatment Advancing rapidly Better, more powerful machines New sophisticated approaches Intensity Modulated RT (IMRT) Image-Guided RT (IGRT) Proton Therapy

13 External Beam Treatment Machines 1920 s Low energy Poor penetration Unable to treat the prostate without skin toxicity 1950s Moderate Energy Improved penetration Less skin toxicity Today Computer controlled Linear accelerators Multiple high energy beams IMRT and IGRT

14 Conventional Prostate RT Multiple beams focused on the prostate Attempts made to shield surrounding normal rectum and bladder Considerable volumes of normal tissues treated exposing patients to toxicity

15 Intensity Modulated RT (IMRT) Novel RT approach First developed in the early 1990s Increasingly popular today Use of computers to conform the radiation dose in 3 dimensions to the shape of the prostate ( shrink wrap ) Reduces dose to bladder and rectum Reduces toxicity risk

16 IMRT field divided into different beamlets Conventional RT field with shaped edges The beam has equal intensity across its surface

17 IMRT in Prostate Cancer IMRT Plan Conventional RT

18 IMRT in Prostate Cancer Better focusing allows us to reduce risk of toxicity to rectum and bladder Also allows us to safely use higher doses to improve cure rates Also being used to potentially reduce risk of impotence by reducing irradiation of the penile bulb

19 RT in Prostate Cancer Results of RT in prostate cancer now rival surgery Long-term comparisons show comparable cure rates for early stage patients

20 Prostate IMRT Higher doses possible with IMRT may result in better PSA control rates Memorial Sloan Kettering Data Favorable n=275 Intermediate n=322 Unfavorable n=175

21 RT and Prostate Cancer Excellent results also achieved treating patients with a rising PSA after prostatectomy If initiated prior to significant rise in PSA, high cure rates are possible Also commonly used to improve the outcome of patients who undergo surgery but have a positive margin

22 Image Guided RT (IGRT) Current interest focused on image guided RT (IGRT) Method to use imaging in the treatment room to improve the delivery of IMRT Not a replacement for IMRT IMRT focuses the radiation on the prostate while IGRT ensures that it is aimed correctly everyday

23 IGRT New Radiation Machines image patients and deliver radiation Allows one to see where the tumor is everyday immediately before treatment Very important since many tumors including prostate cancer may move from day to day If you do not account for movement, you will miss the prostate

24 RT Field Bladder Prostate Bladder Prostate Underdosing Prostate Rectum Rectum Overdosing Rectum

25 Varian On-Board Imaging System Radiation Imaging Varian Trilogy Machine (UCSD)

26 IGRT and Prostate Cancer Two Approaches Track implanted (non-radioactive) seeds in the prostate Perform daily CT scans of the prostate Both methods allow the treatment beams to be re-adjusted based on prostate location

27 On-Board Imaging IGRT DRR Planning Film OBI Small gold seeds implanted in prostate IGRT system used to match position everyday <1-2 minutes Other IGRT Systems (CyberKnife) also uses this approach

28 On-Board Imaging IGRT DRR Planning Film OBI A more sophisticated method is to perform daily CT Used to ensure proper alignment of prostate Avoids need to implant seed markers Not possible on CyberKnife and other IGRT systems

29 IGRT/IMRT at UCSD Now treated hundreds of patients with IGRT and IMRT with excellent results Currently serve as a training center for physicians around the country and world to learn these techniques

30 IGRT Increasing interest focusing on using sophisticated imaging to improve targeting of IMRT treatment Traditional approaches simply treat the entire prostate New approaches help focus treatment on the tumor itself Allow higher more effective doses to be concentrated on the cancer

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32 Color Doppler

33 Proton Therapy Revolution in the treatment of cancer Protons unlike conventional x-rays enter the body and stop! Allows treatment to be highly focused Proton Treatment Prostate Cancer

34 Proton Therapy Prostate Cancer The future of prostate cancer treatment Current approaches not ideal Unable to do IMRT or IGRT Prostate immobilized by placing a balloon in the rectum everyday New proton machines will be substantially better with ability to do IMRT and localize the prostate with imaging

35 Proton Centers Indiana Boston Loma Linda Philadelphia (2009) Florida Houston

36 Proton Centers Indiana Boston Loma Linda Philadelphia (2009) Florida San Diego UCSD Houston

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38 Conclusions Radiation therapy has a long history in the treatment of prostate cancer Currently RT occupies a major role in the treatment of prostate cancer New approaches (IMRT and IGRT) improve the delivery and efficacy of treatment Proton therapy with IMRT and IGRT is clearly the future

39 Patient Information Treatment Approaches Prostate Cancer IMRT IGRT A.J. Mundt MD Professor and Chair Ajay Sandhu MD Chief, Prostate Cancer Service