November 26 – December 1, 2017
Patients Treated with Volumetric Modulated Arc Therapy for
Prostate Cancer Return to Baseline Urinary Function Following Treatment to 81 Gy
Tuesday 10:50-11:00 AM | SSG16-03 | Room: S104A
Jamie A. Cesaretti, MD,MS
Jacksonville, FL (Presenter)
Mitchell D. Terk, MD
purpose of the abstract was to determine both the acute and long terms consequences of VMAT to 81Gy for prostate cancer in
a cohort of 501 men treated between 8/2010 and 12/2015 using a validated measure of urinary function.
METHOD AND MATERIALS:
Five hundred and one men were
treated with VMAT to 81 Gy from 8/2010 to 12/2015 for low (27.5%), intermediate (47.7% and high risk (24.8%) prostate cancer.
In addition to the use of VMAT, patients were treated using gold fiducial markers, a rectal stabilization device and MRI treatment
planning. All men were given the International Prostate Symptom Score sheet prior to treatment, at one month following treatment
and at one year. IPSS scores were prospectively collected and comparisons of means were made by T-test. The incidence of elevations
in IPSS which have been previously described to be bothersome to men and require either medical or surgical intervention are
IPSS score prior to therapy was 9.57 for the entire cohort, at one month following completion of radiation the average score
was 10.51 (p=0.003) and at one year 9.23 (p=0.17). 119/501 (23.8%) of patients began treatment with an IPSS score great than
or equal to 15 with an average score of 19.65. At one month following treatment the IPSS score was 15.34 (p<0.01) and at
a year 13.9 (p<0.01). For patients with baseline IPSS less than 15, the average score prior to therapy was 6.49, and at
one month and one year 9.01 and 7.66 respectively (p<0.01). For 171 (34.1%) patients who were initially asymptomatic, IPSS
less than or equal to 5, the average IPSS prior to treatment was 2.81, and at one month and one year 7.08 and 6.29 (p<0.01).
When evaluated individually, 111/501 (22.2%) patients experienced a rise in IPSS of at least 5, 46/501 (9.1%) of 10, 15/501
(3.0%) of 15 and 6/501 (1.2%) of 20 points. No patient required catheterization at any point or use of pads.
Patients who were highly symptomatic prior to VMAT therapy
experienced improved urinary function prior to baseline measurements at one month following treatment and continued improvement
on to one year of treatment. Very few patients experienced a clinically signficant rise in IPSS of greater than 15 and 20
from their pretreatment baseline measurements. No patient experienced catheterization or incontinence.
Prostate cancer treatment to very high doses is associated with
minimal urinary toxicity.