Mark L. Merlin, M.D. Radiotherapy Clinics of Georgia 7/14/2010

1. Mark L. Merlin, M.D. Radiotherapy Clinics of Georgia 7/14/2010 The Role of Radiation Therapy in the Management of Prostate Cancer

2. Radiation therapy works by either directly killing cancer cells or by damaging their DNA • Normal tissue cells have a mechanism for repairing DNA damage • Cancer cells have a diminished ability to repair this sub lethal damage • Radiation oncology is a field of medicine that specializes in the destruction of cancer cells using various forms of radiation • Balance normal tissue damage versus eradication of cancer

6. Natural history • If detected early, prostate cancer remains confined to the prostate or immediately adjacent tissues • Spread to surrounding nerves / fatty tissues • Spread to adjacent lymph nodes • Spread to distant sites such as bone

7. Radiation versus Surgery Data is retrospective Patient selection varies Overall data does not suggest one option is better than another Some clinical situations may benefit more from one type of therapy Side effects vary significantly Patients should research all options Focus on cure rates, side effects, and quality of life issues Centers of excellence

8. Radiation therapy options • External beam therapy with photons - IMRT (Intensity Modulated Radiation Therapy) • Brachytherapy • Permanent or temporary seeds • Brachytherapy / External beam therapy • Particle therapy • Protons, Neutrons • Stereotactic radiation • Cyberknife, Tomotherapy

9. External beam therapy Multiple photon beams aimed at a target Patient specific moving shields for normal tissues IMRT – software planning based on CT scan images Daily treatment

10. External beam therapy Photons enter through skin and are directed at target Some exposure to surrounding tissue Improved imaging and computer software

17. Brachytherapy Radiation source is placed inside or next to the area requiring treatment Needles are placed through skin of the perineum Radioactive seeds are implanted through needles Permanent seeds – Iodine, Palladium, Cesium Temporary seeds – Iridium

20. Brachytherapy • Best used alone if the chance for extracapsular spread is low • Chance for extracapsular spread relies on certain clinical factors: • PSA • Gleason score • Number of positive biopsies • Stage (findings on digital rectal exam) • Presence of perineural invasion

21. Brachytherapy combined with External Beam therapy Allows more intense radiation dose to prostate through brachytherapy Allows treatment with external radiation to encompass some areas around prostate for potential spread Combination may overcome limits of either modality on its own

22. Stereotactic Radiation • Focused radiation beams targeting a well defined tumor using extremely detailed imaging scans • Cyberknife • Tomotherapy • Cure rate data following treatment is not available due to short follow-up

24. Particle therapy Special case of external beam radiation where the particles are protons or heavier ions Dose increases while the particle penetrates the tissue up to a maximum that occurs near the end of the particle’s range The dose then drops to almost zero

25. Proton beam therapy • Loma Linda 2004 article • 1255 pts treated with protons for prostate cancer • Overall cure rate 73% • Massachusetts General 2008 article • Recommended further study on protocol before rapid adoption • Cited tremendous increase in price for machines with no proven benefit over current linear accelerators • Protocols for dose, treatment setup, and parameters for shielding uninvolved tissues remain in evolution • Standard long term radiation effects on urinary and rectal function do exist

26. Hormone therapy combined with radiation • Two large randomized studies have shown that patients with locally advanced prostate cancer treated with standard external beam therapy have higher cure rates if they also receive testosterone suppression • EORTC (2002) – GS 8-10 and T1/T2 or any T3/T4 pts • RT alone vs RT + LHRH x 3 yrs • 5 yr OS 62% vs 78% • RTOG (2005) – T3 or N1 • RT alone vs. RT + LHRH x 28 months • 10 yr absol surv 39% vs. 49%

27. Hormone therapy side effects Hot flashes Decrease in muscle tone Weight gain Impotence Decreased libido Fatigue Emotional lability Increased risk of cardiovascular death Breast enlargement / tenderness

28. Radiation following radical prostatectomy Following surgical removal of the prostate, a careful pathological analysis is done Organ confined vs. not confined (seminal vesicle involvement, capsule penetration, or margin involvement) Patients with certain features have a higher risk of cancer recurrence within the prostate bed

29. Radiation following radical prostatectomy • In the past, many patients and physicians have followed the PSA level after surgery • Recent randomized trials suggest that those patients with high-risk features should be evaluated for immediate radiation to the prostate bed • Improved survival rates have been found with immediate vs. delayed radiation • 10 yr OS 71% vs. 61% • Standard of care is to evaluate all high risk patients following surgery for possible radiation therapy

30. Radiation side effects • Acute effects (during treatment) • Urinary • Rectal • General • Late effects (months – years after treatment) • Urinary / Sexual • Rectal • Secondary Cancer

31. Get educated! Do your own research Talk with friends and family Use the internet Get second opinions Read prostate books literature

32. Organizations such as The Prostate Net help to raise public awareness and promote education of available resources Evidence based medicine Centers of excellence with database of prior patients

33. Any Questions?

34. Contact Information Mark L. Merlin, M.D. Radiation Oncologist Phone: 404-633-5606 Ext. 180 Email: mmerlin@rccancercenters.com