Genitourinary Cancer

SS 08 - GU 2 - Long-Term Updates of Prospective Prostate Cancer Clinical Trials

60 - 10-Year Update of a Randomized Prospective Trial of Conventional Versus Hypofractionated Radiation Therapy for Localized Prostate Cancer

Monday, October 22
7:55 AM - 8:05 AM
Location: Room 214 C/D

10-Year Update of a Randomized Prospective Trial of Conventional Versus Hypofractionated Radiation Therapy for Localized Prostate Cancer
V. Avkshtol1, T. Li1, M. A. Hallman1, R. Greenberg1, R. A. Price Jr1, R. G. Uzzo1, C. M. C. Ma2, D. Chen1, D. M. Geynisman1, A. Pollack3, and E. M. Horwitz1; 1Fox Chase Cancer Center, Philadelphia, PA, 2Temple University, Philadelphia, PA, 3University of Miami, Miami, FL

Purpose/Objective(s): We present 10-year disease outcomes of a randomized prospective trial of conventional versus hypofractionated radiation therapy for localized prostate cancer.

Materials/Methods: Between June 2002 and May 2006, men with low- to high-risk prostate cancer were randomized to receive conventionally fractionated intensity-modulated radiation therapy (C-IMRT, 76 Gy in 38 fractions at 2 Gy per fraction) or hypofractionated IMRT (H-IMRT, 70.2 Gy in 26 fractions at 2.7 Gy per fraction) at a single institution. The latter treatment is estimated to have an equivalent dose in 2 Gy fractions of 84.4 Gy assuming an α/β ratio of 1.5. High-risk patients were scheduled to receive 24 months of androgen deprivation therapy (ADT) and some intermediate-risk patients were offered up to 4 months of ADT. The primary end point was the cumulative incidence of biochemical and/or clinical disease failure (BCDF). Biochemical failure (BF) was defined as nadir + 2. In the univariate analyses, Kaplan-Meier estimation was obtained for overall survival (OS) and prostate cancer-specific mortality (PCSM) and cumulative incidence function was estimated for BF and metastatic rate with death as the competing risk. Cox proportional hazard model was done for multivariable analyses (MVA) with adjustment for age, race, ADT, and risk group.

Results: A total of 303 men were randomized to C-IMRT (n = 152) or H-IMRT (n = 151), with 77 men being lost to long-term follow up. Median follow up for the whole cohort was 130 months (range 7 – 181 months). There were 28 (9.2%), 189 (62.4%), and 86 (28.4%) NCCN favorable-, intermediate-, and high-risk patients, respectively. The arms were equally balanced for clinicopathologic factors, except there were more African-Americans in the C-IMRT arm (17.8% vs 7.3%; p = 0.02). ADT was taken by 46.7% and 45% of men in the C-IMRT and H-IMRT arm, respectively (p = 0.97). The median length of ADT treatment was 23.9 and 23.7 months in the C-IMRT and H-IMRT arm, respectively (p = 0.94). On MVA, 10-year BCDF was similar in both arms (25.9% in the C-IMRT arm and 30.6% in the H-IMRT arm; HR 1.42, 95% CI 0.91 – 2.46; Table 1). The two treatment groups also had similar rates of 10-year BF, PCSM, and OS. The H-IMRT arm did have a trend toward higher 10-year metastatic rate (5.3% vs 12.7%; HR 2.12, 95% CI 0.97 – 4.63; Table 1).

Conclusion: H-IMRT demonstrated no differences in disease outcomes when compared to C-IMRT. There was a trend of increased risk of developing metastases in the H-IMRT arm for which further follow up is underway.
Table 1. Disease Outcomes by Treatment Group
5-year 10-year

MVA

Outcome C-IMRT % H-IMRT % C-IMRT % H-IMRT % HR 95% CI p-value
BF 9.1% 11.9% 21.2% 25.4% 1.26 0.74 – 2.2 0.4
Metastatic rate 4% 7.3% 5.3% 12.7% 2.12 0.97 – 4.63 0.06
BCDF 12% 17.4% 25.9% 30.6% 1.42 0.86 – 2.32 0.17
PCSM 1.3% 2.7% 2.7% 4% 1.27 0.4 – 4.1 0.69
OS 92.7% 89.4% 78.4% 71.1% 1.43 0.93 – 2.19 0.1

Author Disclosure: V. Avkshtol: None. T. Li: None. M.A. Hallman: None. R.A. Price: None. R.G. Uzzo: None. C. Ma: Employee; Fox Chase Cancer Center. Committee Member; AAPM. D. Chen: None. D.M. Geynisman: None. A. Pollack: Research Grant; Radiation Therapy Oncology Group, Varian Medical Systems. Honoraria; Mayo Clinic, City of Hope. Consultant; Medivation. Travel Expenses; Radiation Therapy Oncology Group, Mayo Clinic, Rio Oncology, Varian Medical Systems Inc, IBA Proton Therapy, City of Hope.

Vladimir Avkshtol, MD

Fox Chase Cancer Center

Disclosure:
No relationships to disclose.

Presentation(s):

Send Email for Vladimir Avkshtol


Assets

60 - 10-Year Update of a Randomized Prospective Trial of Conventional Versus Hypofractionated Radiation Therapy for Localized Prostate Cancer



Attendees who have favorited this

Please enter your access key

The asset you are trying to access is locked. Please enter your access key to unlock.

Send Email for 10-Year Update of a Randomized Prospective Trial of Conventional Versus Hypofractionated Radiation Therapy for Localized Prostate Cancer