Intensity Modulated Radiation Therapy IMRT for Prostate Cancer - PowerPoint PPT Presentation

Loading...

PPT – Intensity Modulated Radiation Therapy IMRT for Prostate Cancer PowerPoint presentation | free to view - id: ff4aa-ZDc1Z



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Intensity Modulated Radiation Therapy IMRT for Prostate Cancer

Description:

1. Technical aspects of radiation delivery including IMRT ... 3D Dosimetry. IMRT Dosimetry. IMRT Dosimetry Prostate Cancer. Prostate IMRT Post-Prostatectomy ... – PowerPoint PPT presentation

Number of Views:1231
Avg rating:3.0/5.0
Slides: 45
Provided by: Bqua
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Intensity Modulated Radiation Therapy IMRT for Prostate Cancer


1
Intensity Modulated Radiation Therapy (IMRT) for
Prostate Cancer
  • Brian P. Quaranta, MD
  • 21st Century Oncology
  • Asheville, NC, USA

2
Outline
  • 1. Technical aspects of radiation delivery
    including IMRT
  • 2. Why IMRT is better than 3D
  • 3. Goals and results of IMRT
  • 4. Potential disadvantages
  • 5. Summary

3
Part 1
  • Technical Aspects

4
The Progression of Technology
  • In order to understand what were doing now, and
    where were going, its necessary to be
    acquainted with the past

5
1970s 1980s
  • Treatment plans designed using x-rays and lead
    blocks
  • Ability to localize the prostate limited b/c soft
    tissue structures not well visualized with x-rays
  • Prostate cancer treatment doses were generally in
    the range of 60 Gy

6
1980s-1990s 3D Conformal Radiation
  • Patient has CT scan in treatment position
  • Radiation oncologist outlines the prostate,
    seminal vesicles, bladder, rectum, femoral heads
  • Computer then generates a 3D representation of
    all of the structures and their spatial
    relationships
  • Radiation oncologist can use this information to
    design beams that more accurately target tumor
    and avoid normal tissues
  • Increased confidence in location resulted in
    smaller fields, which led to higher doses,
    generally around 70 Gy

7
21st Century IMRT
  • Stands for Intensity-Modulated Radiation
    Therapy
  • Often touted as a new treatment in fact it is
    a new way of delivering good old photons
  • Means that the dose delivered through the beam
    aperture is different in different locations the
    intensity of the beam is modulated intentionally
  • Has allowed increase of dose into the 76-81 Gy
    range

8
How to modulate the beam
  • Method 1 Dynamic multi-leaf collimator
  • Method 2 Individually computer designed brass
    modulators
  • Two different approaches that achieve the same
    goal

9
MLC in action
10
Modulator-Based IMRT
  • Multiple beams are designed
  • Computer and planning team design each beam
    including how much dose should be delivered
    through each portion of the beam
  • For each beam, a brass modulator is designed by
    computer to allow a certain percentage of the
    beam energy to pass through

11
  • A complete set of modulators for a prostate
    treatment

12
(No Transcript)
13
IMRT Notes
  • Patients usually receive 5-7 beams per day
  • Treatment is given 5 days per week for about 8
    weeks
  • Patient lies on a table and receives high-energy
    x-rays
  • It does not hurt
  • Side effects accumulate slowly over time
  • Acutely they generally they include mild fatigue,
    urinary irritation, and bowel irritation

14
Machine delivering treatment at 21st Century
Oncology
15
Part 2. Why IMRT Is Superior to 3D
  • Modulating the beam allows for superior control
    of the dose

16
3D Dosimetry
17
IMRT Dosimetry
18
IMRT Dosimetry Prostate Cancer
19
Prostate IMRT Post-Prostatectomy
20
Part 3. Goal of IMRT
  • To deliver higher doses than with 3D technique
    while maintaining or improving the side effect
    profile.

21
Side effects
  • Definitions
  • Late gastrointestinal toxicity
  • Grade 2 moderate diarrhea and colic bowel
    movement gt 5x/day intermittent bleeding
  • Grade 3 obstruction or bleeding requiring
    surgery
  • Late genitourinary toxicity
  • Grade 2 moderate frequency intermittent
    hematuria
  • Grade 3 severe frequency and dysuria frequent
    hematuria reduction in bladder capacity lt150 cc

22
IMRT side effects 1
  • Vora et al, Mayo Clinic, 2007
  • 416 patients treated with 3D or IMRT
  • 3D dose 68.4 Gy
  • IMRT dose 75.6 Gy
  • Late toxicity
  • 3D 68.4 Gy IMRT 75.6 Gy
  • Gr 2 GU 17 23
  • Gr 3 GU 5 6
  • Gr 2 GI 14 23
  • Gr 3 GI 2 1
  • No significant differences

23
IMRT side effects 2
  • Su et al (U Chicago) 2006
  • Compared 355 pts treated with 3D to 70 Gy with
    106 patients treated with IMRT to 76 Gy
  • 3D 70 Gy IMRT 76 Gy
  • GI Gr 2 8 3
  • GI Gr 3 3 3
  • GU Gr 2 21 19
  • GU Gr 3 2 4
  • Despite higher dose, IMRT patients had the same
    chronic GU toxicity and significantly less GI
    toxicity

24
More on Safety Compared to 3D treatment, IMRT
allows us to
  • Decrease bowel toxicity and sexual dysfunction
    (Namiki et al 2006)
  • Decrease bowel toxicity (Sanguineti et al 2006,
    Jani et al 2006)
  • Reduce bowel treated to high dose in whole-pelvic
    RT (Ashman et al 2005, Nutting et al 2000 )
  • Spare penile structures and potentially reduce
    sexual dysfunction (Kao 2004)

25
ConclusionIMRT allows increased dose with the
same or lower rates of toxicity
26
Critical Point for Understanding Radiation Therapy
  • Almost any localized tumor can be cured by
    radiation therapy
  • All you have to do is administer enough dose

27
The Trick
  • is to be able to give enough dose without
    excessively damaging the patient
  • With some tumors (lung, brain, pancreas) we have
    not been very successful at this
  • With prostate cancer, we have made significant
    strides

28
Benefits of Dose Escalation 1
  • Zeitman et al, 2005, Massachusetts General
    Hospital, Randomized trial
  • 393 Patients with localized disease
  • Randomized to 70.2 vs. 79.2 Gy
  • Boost was delivered via proton beam
  • 5 yr PSA control was 80.4 vs. 61.4

29
Benefits of Dose Escalation 2
  • Peeters et al 2006
  • 669 Patients with T1-4 prostate cancer
  • Randomized to 68 vs 78 Gy
  • FFS improved with higher dose
  • 64 vs 54

30
What have we learned?
  • Answer
  • 1. IMRT enables us to deliver higher doses
    safely
  • 2. Three randomized trials demonstrate that
    Higher doses are more effective at controlling
    prostate cancer

31
Results of IMRT
  • Patients should be stratified by risk group
  • Low risk PSA lt10, GS lt6, T1 or T2a
  • Intermediate Risk PSA 10-20 or GS 7 or T2c
  • High Risk PSA gt20 or GS gt8 or T3
  • Prognostic value of these groups has been
    validated in numerous studies

32
Sloan-Kettering 3D (n743) and IMRT (n772)
  • PSA Control Rates
  • (Risk group)
  • Dose Low Intermediate High
  • (Gy) () () ()
  • 3D 64-70 59 42 21
  • 3D 76 81 60 42
  • 3D 81 98 87 70
  • IMRT 81-86 92 86 81

33
Sloan-Kettering 3D and IMRT
  • Toxicity
  • Late Grade 2-3 GI toxicity
  • MSKCC 3D gt75 Gy 17
  • MSKCC IMRT 81-86 Gy 2

34
IMRT Results 2 Mayo Clinic Scottsdale
  • 271 pts treated with 3D to 68.4 Gy
  • 145 pts treated with IMRT to 75.6 Gy
  • 5 yr PSA Relapse-Free survival
  • 3D 68.4 Gy IMRT 75.6 Gy
  • Low 76 87.5
  • Int 50.1 72.6
  • High 35 60.2

35
IMRT Results 3 Ghent, Belgium
  • 133 pts treated with IMRT
  • Dose 74-76 Gy
  • Intermediate and high-risk patients had
    concurrent androgen deprivation
  • 5 year PSA relapse-free survival
  • Low 100
  • Int 94
  • High 74

36
Results Conclusions
  • Dose escalation results in superior control of
    prostate cancers
  • IMRT allows delivery of higher doses than 3D
    treatment with equal or reduced side effects
  • Published data support excellent results for IMRT

37
Sloan-Kettering Recommendations
  • Despite the added labor intensity necessary
    for quality assurance and treatment verification
    for the implementation of IMRT, the superior dose
    distributions, resulting in enhanced conformality
    achieved with this technique, make IMRT the
    approach of choice for high-dose radiotherapy
    delivery.
  • Zelefsky et al 2002

38
Part IV Things to consider about IMRT
  • Time Effort
  • Longer treatment planning
  • Ties up computers
  • Physicists need to
  • Provide QA, often
  • After hours
  • Cost

39
Treatment Comparisons
40
  • Low-Risk Patients
  • Treatment Study 5 yr PSA control
  • Surgery Sharkey 2002 92
  • Duke 2002 89
  • U Penn 1998 83
  • Johns Hopkins 2001 95
  • Seeds Seattle 2000 94
  • MSKCC 2000 88
  • IMRT MSKCC 2006 92
  • Mayo 2007 87.5
  • Ghent 2007 100

41
  • Intermediate-Risk Patients
  • Treatment Study 5 yr PSA control
  • Surgery Sharkey 2002 72
  • Duke 2002 69
  • U Penn 1998 65
  • Johns Hopkins 2001 73
  • Seeds Seattle 2000 82
  • MSKCC 2000 77
  • IMRT MSKCC 2006 86
  • Mayo 2007 72.6
  • Ghent 2007 94

42
  • High-Risk Patients
  • Treatment Study 5 yr PSA control
  • Surgery Sharkey 2002 52
  • Duke 2002 40
  • U Penn 1998 30
  • Johns Hopkins 2001 44
  • Seeds Seattle 2000 65
  • MSKCC 2000 38
  • IMRT MSKCC 2006 81
  • Mayo 2007 60.2
  • Ghent 2007 74

43
Why does IMRT look so good for high-risk patients?
  • Chance for extracapsular extension is 60 or
    higher in this group of patients
  • IMRT allows us to treat tissue around the
    prostate in addition to the prostate itself
  • Surgery and seed implants are more localized
    treatments

44
Conclusions
  • IMRT allows for safe delivery of higher doses
    compared to prior external radiation treatments
  • This has allowed for improved PSA control rates
    and decreased side effects
  • These results appear to compare favorably to
    other treatment methods
  • IMRT is the preferred method for radiation
    treatment
About PowerShow.com