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

The prostate lies along the back of the bladder

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

Prostate Zones: 80-85% cancers arise from the peripheral zone, 10-15% transitional and 5-10% from the central zone.

The peripheral zone is small at the top (base) of the gland but larger at the bottom (apex)

Cancer occurs along the outside edge of the prostate just under the capsule

cancer

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

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

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

There are lymph nodes that may be involved, it is rare to have lymph node spread in low or intermediate risk patients

CT scans and MRI show the anatomy of the prostate quite well

Prostate Cross Section Anatomy

Prostate

rectum

bladder

Cross section anatomy of the male pelvis

Cross section anatomy of the male pelvis

Bladder

Prostate

Rectum

Prostate CT Anatomy

CT Scan = large prostate cancer

MRI showing Cancer Nodule

Prostate Stages

Most men with a low PSA (less than 10) and a low Gleason score (less than 7) have cancer cells in the gland too small to feel or see on CT scans

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 LevelRelapsed 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

Note that the PSA levels slowly decline after completing radiation

Declining PSA After External + Seeds

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 scoreSo the slowest is a 2 and thefastest is a 10.

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

Gleason Score

50

55

60

65

70

75

80

85

90

95

6 7 8

5 YearSurvival

10 YearSurvival

60

65

70

75

80

85

90

95

3+3 3+4 4+4 4+5 5+5

5 year cure rate radiation

radiation plus hormones

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

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

bladder

Radiation zone

prostate

rectum

Goal = radiation zone precisely around the prostate cancer with small margin

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

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

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 Tomotherapyand 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

Using Tomotherapy to tightly target the prostate with very little radiation hitting

the bladder or rectum

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

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

Radiationzone

Irritation of bladder, urethra and rectum

Radiationzone

1. Urinary frequency (getting up at night very few hours)

2. Slight burning or stinging with urination

3. Diarrhea or more frequent, softer bowel movements, rectal soreness

4. Mild skin irritation

5. Fatigue

Long Term Side Effects of Radiation

Typical Radiation Protocols for Low Risk

•Daily external beam radiation, Monday through Friday for ~ 8weeks

•Seeds (one time)

•Combination: 5 weeks or external radiation then 3-5 weeks later a seed implant

Typical Radiation Protocols for More Advanced Risk Group

•May start with hormonal therapy (e.g. Zoladex or Lupron) for several months prior to starting radiation

•May need to continue on hormone therapy for up to 2 to 3 years

Radiation prescription for #

Diagnosis: #

Hormones: #

Seeds: #

External radiation: #