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Volume 87 � Number 2S � Supplement 2013 Poster Viewing Abstracts S355
(IMRT) used after that time (dose prescribed to encompass at least 98%
of the cl-PTV).
Results: One thousand seven hundred seventeen patients were available
for analysis. Median follow-up was 4.9 years (range, 0.6-17.1 years).
Thirty-seven percent of patients underwent 3DCRT and 63% IMRT.
Median prescription dose was 75.6 Gy for patients with low-risk and 77.4
Gy for patients with intermediate and high-risk disease. Overall 10-year
biochemical failure (BF) rate was 29%: 18% for low-risk, 32% for inter-
mediate-risk, and 49% for high-risk patients. Clinical failure rates were
1%, 5%, and 10%, respectively, for the 3 risk groups. Ten-year likelihood
of biopsy-proven local failure was <1%, and overall local failure rate
(biopsy proven plus BF without regional or distant disease) was 13%. Ten-
year rates of distant metastases were 0.5%, 3.8%, and 10.3%, and cause-
specific survival was 99%, 99%, and 93% for low, intermediate, and high-
risk patients, respectively. Chronic grade >2 gastrointestinal and genito-
urinary toxicity was 18.5% and 23.8% for the entire cohort, respectively,
and 9.2% (<1% grade 3) and 18.8% for those receiving IGART in
combination with IMRT.
Conclusions: Image guidance using an off-line, adaptive technique was
associated with excellent clinical outcomes in a large patient cohort with
extended follow-up. This data provides strong support for continued
implementation and development of IGRT techniques in standard prostate
cancer management.
Author Disclosure: D.J. Krauss: None. D. Yan: None. G.S. Gustafson:
None. H. Ye: None. N. Tonlaar: None. P.Y. Chen: None. G.Z. Gustafson:
None. L.L. Kestin: None. A.A. Martinez: None. D.S. Brabbins: None.
2397Update of Risk Factors for Biochemical Recurrence of ProstateCancer After Salvage Radiation Therapy Post-Radical ProstatectomyR.J. Lee, K.S. Tzou, M.G. Heckman, B. Rawal, J.L. Peterson,
N.N. Paryani, S.J. Ko, and S.J. Buskirk; Mayo Clinic Jacksonville,
Jacksonville, FL
Purpose/Objective(s): Our group has previously evaluated risk factors forbiochemical recurrence (BCR) of prostate cancer after salvage radiation
therapy (SRT) with BCR defined as a prostate-specific antigen (PSA) value
of 0.4 ng/mL and rising. We now report an update of these risk factors
using the current American Urological Association (AUA) definition of
BCR as a PSA value of 0.2 ng/mL and rising.
Materials/Methods: This is a retrospective review of 308 patients who
received SRT for a rising PSA following radical prostatectomy (RP)
between June 1988 and February 2012 at our institution. Pre-RP PSA, pre-
SRT PSA, SRT dose, age, length of time between RP and SRT initiation,
pathological tumor stage, surgical margin, Gleason score, and pre-SRT
hormone therapy were all evaluated as risk factors for BCR using relative
risks (RR) from Cox proportional hazards regression models. BCR was
defined in accordance with the current AUA guidelines.
Results: Median pre-RP PSAwas 7.3 ng/mL (<0.1-108.0 ng/mL), median
pre-SRT PSA was 0.6 ng/mL (<0.1-23.3 ng/mL), and median SRT dose
was 66.6 Gy (60.0-72.0). With a median follow-up of 5.6 years (0.3-20.6
Poster Viewing Abstract 2398; Table Factors evaluated as predictors of grade 2 proc
Freedom from grade >2 proctitis
Treatment TypeBT/BT+EBRT/BT+ADT/BT+ADT+EBRT
92.8%/93.5%/95.8%/93.1%
BEDLess than 219 Gy/Greater than 219 Gy
94.1%/91.1%
RV100<1.5 cc/>1.5 cc
95.2%/88.1%
Alcohol +/-(n Z 1257)
94.3%/92.9%
CAD +/-(n Z 154)
93.9%/89.6%
years), 191 patients (62%) experienced BCR. At 5 and 10 years following
the start of SRT, estimated cumulative incidences of BCR were 62% (95%
Confidence Interval [CI]: 56-68%) and 75% (95% CI, 67-81%), respec-
tively. In multivariable analysis, pre-SRT PSA (RR [per each doubling]:
1.21, p < 0.001), pathological tumor stage (RR [T3a vs T2]: 1.18, p Z0.32; RR [T3b/T4 vs T2]: 2.19, p < 0.001; overall P1.0 ng/mL, compared
to patients with a pre-SRT PSA �1.0 ng/mL. Positive surgical margin was
associated with a decreased risk of BCR (RR: 0.71, p Z 0.028), but this
did not remain significant after adjustment for multiple testing.
Conclusions: This review confirms that pre-SRT PSA, pathological tumor
stage, and Gleason score are independently associated with BCR following
SRT, using the current AUA definition for BCR. Risk of BCR was highest
for patients with a pre-SRT PSA level above 1.0 ng/mL, T3b/T4 patho-
logical tumor stage, and a Gleason score greater than 7.
Author Disclosure: R.J. Lee: None. K.S. Tzou: None. M.G. Heckman:
None. B. Rawal: None. J.L. Peterson: None. N.N. Paryani: None. S.J. Ko:
None. S.J. Buskirk: None.
2398Predictive Factors and Management of Rectal Bleeding Side EffectsFollowing Prostate Cancer BrachytherapyJ. Price, N.N. Stone, and R.G. Stock; Icahn School of Medicine at Mount
Sinai Hospital, New York, NY
Purpose/Objective(s): We report on the incidence, nature, and manage-
ment of rectal toxicities following brachytherapy treatment for prostate
cancer over a 17-year period. We also report the patient and treatment
factors predisposing to acute Grade 2 proctitis.
Materials/Methods: A total of 2,752 patients were treated for prostate
cancer between October 1990 and April 2007 with either brachytherapy
alone or in combination with androgen depletion therapy or external beam
radiation therapy and were followed for a median of 6.47 years. We
investigated the incidence, nature, and treatment of acute and chronic
rectal toxicities following BT. Using univariate and multivariate analyses
we determined the treatment and comorbidity factors predisposing to rectal
toxicities. We also outline the most common and effective management for
these toxicities.
Results: Overall incidence of Grade 2 rectal bleeding was 6.4%, although
notably only 0.9% of all patients required medical intervention to manage
this toxicity. The majority of rectal bleeding episodes (72%) occurred
within the first 3 years following placement of BT seeds. Of the 27 patients
requiring management for rectal bleeding, 18 underwent formalin treat-
ment and 9 underwent cauterization. Post-hoc univariate statistical analysis
revealed that alcohol use, history of coronary artery disease (CAD), BED,
RV100, and treatment modality predict the likelihood of Grade �2 rectal
bleeding. Alcohol, CAD, treatment modality, and RV100 fit a Cox-
regression multivariate model in predicting predisposition to grade 2 rectal
bleeding.
Conclusions: Prostate brachytherapy is very well tolerated and rectal
bleeding toxicities are either self-resolving or effectively managed by
medical intervention. Treatment planning incorporating adjuvant ADT
titis
Univariate analysis P value Multivariate analysis P value
ns/ns/.009/ns .013
.01 .141
.0001 .0001
.025 .027
.026 .010