Download 2009 Focused Study on Low Dose Rate Prostate Brachytherapy

2009 Focused Study on Low
Dose Rate Prostate
Brachytherapy Preplan Volumes
Utilizing Ultrasound vs. MRI
Geoffrey Johnson, M.D.
Background
• St Mary Corwin (SMC) has diagnosed
typically between 100-150 prostate
cancers yearly over the past decade
Number of Prostate Cases Diagnosed Past 10 years
1999-2008- at SMC
2008
2007
2006
Years
2005
2004
2003
2002
2001
2000
1999
0
20
40
60
80
100
No. of Cases
120
140
160
180
Background
• Compared to the National
Cancer Database (NCDB), prostate
cancer patients diagnosed at SMC are
more likely to have stage II prostate
cancer and are less likely to have more
advanced disease
Stage of Disease-Prostate Cancer 2000-2006
St. Mary Corwin (SMC) vs. National Cancer Data Base (NCDB)
SMC
unknown
SMC
Stage
IV
SMC
III
SMC
NCDB
SMC
II
SMC
I
0
10
20
30
40
50
Percent %
60
70
80
90
100
Background
• SMC diagnosed more men in their 70s
and less men in their 80s as compared to
NCDB data
Age Distribution of Prostate Ca-Diagnosed 2000-2006
St. Mary Corwin (SMC) vs. National Cancer Data Base (NCDB)
SMC
90+
SMC
Age Groups
80-89
SMC
70-79
SMC
NCDB
SMC
60-69
SMC
50-59
SMC
40-49
0
5
10
15
20
25
Percentage of Cases
30
35
40
45
50
Background
• Since 2002, there has been a trend for
increasing percentage of patients
receiving surgery (including cryotherapy)
for prostate cancer treatment at SMC
• Since 2005, a trend reveals a higher
percentage of patients receiving radiation
for prostate cancer treatment are treated
without hormonal therapy at SMC
SMC
Prostate Cancer-1999 through 2008
Type of Treatment
70
60
Percent
50
40
Radiation
Rdt/Horm.
Surgery
30
20
10
0
1999
2000
2001
2002
2003
2004
10 Year Span
2005
2006
2007
2008
Background
• From 2000-2006, compared to NCDB
data, more prostate cancer patients at
SMC were treated with radiation and
hormones and less are treated with
surgery
Tx of Prostate Ca Diagnosed from 2000- 2006
St. Mary Corwin (SMC) vs. National Cancer Data Base (NCDB)
SMC
No 1st Crse
NCDB
SMC
Treatment Type
Other Txs
NCDB
SMC
Hrms only
NCDB
SMC
NCDB
SMC
Rad.& Hrms
NCDB
SMC
Rad. Only
NCDB
SMC
Surg. Only
NCDB
0
5
10
15
20
25
Percentage
30
35
40
45
Background
• Compared to NCDB data, at SMC from
2000-2006, less prostate cancer patients
received external beam radiation, although
a similar percentage received
brachytherapy
Prostate Cancer-Radiation Therapy- Years 2000-2006
St. Mary Corwin (SMC) vs National Cancer Data Base (NCDB)
60
50
Percentage
40
NCDB
30
SMC
20
10
0
No Rdt
Beam Rdt
Brachy Tx
Type of Radiation
Rad. Isotps
Rdt NOS
Background
• Prior to undergoing brachytherapy, at SMC
patients undergo an ultrasound (US)
volume study for preplanning radiation
source positioning
Background
• Magnetic Resonance Imaging (MRI) is
superior to US for detailing prostate gland
anatomy as well as the extent, location
and spread of cancer within and around
the prostate gland
Background
• This pilot study was designed to see if
differences in preplanning prostate
volumes would result from fusing an
endorectal coil MRI with the US obtained
during the volume study
• In this way, the utility of endorectal coil
MRI – US fusion may be elucidated in an
effort to better preplan brachytherapy for
prostate cancer patients
Method
• 9 consecutive patients who had endorectal
coil MRI performed prior to prostate
brachytherapy in 2008-2009 were included
• All patients had preplan US (only)
treatment volumes entered by their
urologists
• All patients had preplan MRI-US fusion
treatment volumes entered by their
radiation oncologist
Results
• In 1 of 9 patients a ~30% difference was
seen between the 2 volumes
• In another 4 of 9 patients an ~10%
difference was seen
• In the remaining 4 of 9 patients there was
little difference between the 2 volumes
60.00
50.00
40.00
US VOLUME (cc)
30.00
MRI VOLUME (cc)
20.00
10.00
0.00
1
2
3
4
5
6
7
8
9
Conclusion/Discussion
• No firm conclusion can be drawn from this pilot
study due to lack of statistical power
• However, the study did suggest that a difference
may exist
• If a larger study is undertaken, and a difference
between volumes confirmed, US-MRI fusion
may prove to be superior due to its ability to
more accurately define anatomy and pathology
• Future studies confirming an improvement in
clinical outcomes would be necessary to change
the standard approach to these patients