5. Side View of the Prostate, Cancers arise in the peripheral zone , close to the capsule The location of cancer in the prostate is critical for targeting the correct area
6. Prostate Zones: 80-85% cancers arise from the peripheral zone, 10-15% transitional and 5-10% from the central zone.
7. The peripheral zone is small at the top (base) of the gland but larger at the bottom (apex)
8. Cancer occurs along the outside edge of the prostate just under the capsule cancer
9. Cancer occurs along the outside edge of the prostate just under the capsule, so the radiation field may need to extend slightly outside the capsule cancer cancer
10. Risk of Extracapsular Spread for T1c, based on Gleason and PSA You can estimate the risk that the cancer has already grown into the capsule , this helps the doctor determine how large an area to treat
32. Prostate Cancer Cure Rate After Radical Prostatectomy Based on PSA Prior to Surgery
33. PSA (prostate specific antigen) and radiation results PSA Level Relapsed after Radiation 0.1 to 4 4% 4 to 10 7% 10 to 20 22% 20 - 50 48% over 50 67%
34. Note that the PSA levels slowly decline after completing radiation
35. Note that the PSA levels slowly decline after completing radiation
38. Prostate Cancer Cure Rate After Radical Prostatectomy Based on Pathologic Grade (i.e. how mutated the cancer cells appear)
39. Gleason Scoring System From the biopsy, the pathologist grades the appearance of the cells. From least serious (slow growing or Grade 1) to the fastest growing and most dangerous or grade 5). The Gleason score doubles the score So the slowest is a 2 and the fastest is a 10.
40. The higher the Gleason Score, the lower the cure rates after surgery Gleason Score
41. The higher the Gleason Score, the lower the cure rates after radiation Gleason Score
52. Cure Rates with Radiation versus Surgery for Early Stage Prostate Cancer are the same from the Cleveland Clinic. Kupelian. JCO Aug 15 2002: 3376-3385
53. CT scan is obtained at this time CT images are then imported into the treatment planning computer
54. In the simulation process the CT and PET scan images are used to create a computer plan
55. bladder Radiation zone prostate rectum Goal = radiation zone precisely around the prostate cancer with small margin
56. The CT scan images are then converted into a 3 dimensional view inside the patient You can actually see inside the man’s body and locate the key organs
58. IMRT using 7 different beams to target the prostate The computer can determine the optimal number of beams to deliver the radiation dose to hit the target and avoid other structures
59. IMRT The radiation dose clouds that surround the target bladder prostate rectum
60. The computer identifies targets and using IMRT techniques applies low doses to some structures (like lymph nodes) and high doses to the main target (prostate)
61. Even if the prostate has been removed radiation can be used to target the prostate bed (Tomo)
62. In the treatment the lasers are used to line up the beam and the patient receives the radiation treatment
63.
64. Combine a CT scan and linear accelerator to ultimate in targeting (IGRT) and ultimate in delivery (dynamic, helical IMRT) ability to daily adjust the beam (ART or adaptive radiotherapy)
65.
66. With Tomotherapy the beam can hit the target (nodes) in the upper abdomen and avoid the bladder and small intestine and lower in the pelvis hit the prostate, nodes and seminal vesicles and still avoid the bladder and rectum
67. With daily image guided with a CT using Tomotherapy, radiation field can be very tight (‘close’) around prostate
68. Significant movement of the prostate gland based on daily gas in rectum Planned target Rectal gas No Rectal gas Planned target, missed badly if rectal gas pushes the prostate forward
69. Significant movement of the prostate gland based on daily gas in rectum Initial computer target for prostate (red circle) would have badly missed the target if no adjustments were made based on the amount of rectal gas
70. Importance of daily CT targeting on Tomotherapy and adjusting the treatment daily Very little bowel gas on initial study and the dose (red) targets the prostate gland closely large bowel gas on later treatment day and the dose (red) will cover half the rectum if an adjustment is Not made
87. The Mick ‘Gun’ is used to push the radioactive seeds into the gland
88. The seeds are left behind, distributed through the gland and slowly radiate the cancer
89. CT scans of the prostate will show the seeds and the studies will be used to calculate the radiation dose
90. Side Effects of Prostate Radiation Is related to the size and area of normal structures that are over lapped by the radiation zone…the goal is to keep the radiation zone as small as possible
91. Side Effects of Prostate Radiation With IMRT and image guided techniques the goal is to shape the radiation zone very precisely , based on the type of cancer (high Gleason might require a larger margin around the gland)
92. Side Effects of Prostate Radiation The structures that will get radiation irritation: bladder, urethra and rectum Radiation zone