Prostate Cancer

Understanding the disease

Treatment options

Side effects of treatment

Understanding prostate cancer

Anatomy

Importance of Stage

Importance of the Gleason Score

Significance of the PSA

The prostate gland has a capsule around it, and cancers arise close to the capsule

Prostate Anatomy…the nerves that can results in impotence are on the side of the gland

There are lymph nodes that may be involved

CT scans and MRI demonstrate the anatomy of the prostate well

Prostate CT Anatomy Prostate rectum bladder

Cross section anatomy of the male pelvis

Bladder Prostate Rectum Prostate CT Anatomy

CT Scan = large prostate cancer

MRI showing Cancer Nodule

Prostate Stages

T1c = too small to feel and biopsied because of an elevated PSA

T2 lesion = big enough to feel

T3 if spread to the seminal vesicles

Stage IV if spread to the lymph nodes or bone

Prostate Cancer Cure Rate After Radical Prostatectomy Based on Pathologic Stage

Prostate Cancer Cure Rate After Radical Prostatectomy Based on PSA Prior to Surgery

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%

Note that the PSA levels slowly decline after completing radiation

Prostate Cancer Cure Rate After Radical Prostatectomy Based on Pathologic Grade (i.e. how mutated the cancer cells appear)

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.

The higher the Gleason Score, the lower the cure rates after surgery Gleason Score

The higher the Gleason Score, the lower the cure rates after radiation Gleason Score

Prostate Cancer Risk Groups

Low risk : (T1c, T2a Gleason 6, PSA <10)

Intermediate risk : (T2b, T2c, Gleason 7, PSA 10-20)

High risk : (T3, Gleason 8-10 or PSA > 20)

What is considered the proper treatment for prostate cancer?

Advice from the AUA (American Urologic Association)

Advice from the NCCN (National Comprehensive Cancer Network)

Treating prostate cancer Surgery? Radiation?

American Urologic Association (AUA) came out with new treatment guidelines for prostate cancer in 2007

AUA: results the same for all three treatment modalities PSA Cure Rates Seeds External Surgery Low risk Intermediate High

RT = radiation therapy. IMRT = intensity modulated radiation therapy, IGRT = image guided RT e.g. Tomotherapy Brachytherapy = seeds

RT = radiation therapy. IMRT = intensity modulated radiation therapy Brachytherapy = seeds Androgen deprivation therapy = Lupron or Zoladex shots

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

CT scan is obtained at this time CT images are then imported into the treatment planning computer

In the simulation process the CT and PET scan images are used to create a computer plan

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

IMRT Identify organs and tumor target prostate rectum bladder

bladder Radiation zone prostate rectum Goal = radiation zone precisely around the prostate cancer

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

IMRT Intensity modulated radiation therapy The computer then can generate different techniques of delivering the radiation

IMRT Computer will determine the optimal number of beams and beam angles

IMRT The cross sectional CT will show the dose clouds that surround the prostate and how close they are to other vital structures like the bladder or rectum

bladder prostate rectum IMRT The cross sectional image reconstruction of beams and targets

IMRT The radiation dose clouds that surround the target bladder prostate rectum

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)

Even if the prostate has been removed radiation can be used to target the prostate bed (Tomo)

In the treatment the lasers are used to line up the beam and the patient receives the radiation treatment

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)

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

With daily image guided with a CT using Tomotherapy, radiation field can be very tight (‘close’) around prostate

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

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

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

If no adjustment was made Actual treatment on Tomotherapy

Tomotherapy is particularly useful in men with hip replacements

Tampa Bay Cyberknife Center

Cyberknife Radiosurgery

With cyberknife you can use multiple beams from any direction

CyberKnife Multiple beamlets of radiation striking the prostate

bladder prostate rectum Radiation doses are conformed very closely or tightly to prostate avoiding the rectum and bladder

Seed Implants

Prostate Seed Implants

Rectal ultrasound used to image the prostate

A grid or template with holes every 5mm are used to line up the needles

The needles are distributed

The Mick ‘Gun’ is used to push the radioactive seeds into the gland

The seeds are left behind, distributed through the gland and slowly radiate the cancer

CT scans of the prostate will show the seeds and the studies will be used to calculate the radiation dose

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

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)

Side Effects of Prostate Radiation The structures that will get radiation irritation: bladder, urethra and rectum Radiation zone