Phase I/II Study of Hypofractionated Intensity-Modulated Radiotherapy for Prostate Cancer including Simultaneously Integrated Boost

Publication date: Available online 18 September 2017
Source:Practical Radiation Oncology
Author(s): Michael G. Chang, Nitai Mukhopadhyay, Diane Holdford, Vicki Skinner, Siddharth Saraiya, Drew Moghanaki, Mitchell S. Anscher
PurposeTo evaluate the safety and efficacy of moderately hypofractionated radiotherapy with simultaneous integrated boost (HSIB) IMRT that includes coverage of the seminal vesicles (SV) and pelvic lymph nodes (LN).MethodsMen with localized prostate cancer were prospectively enrolled in a phase I/II trial to receive HSIB-IMRT to the prostate, ±SV, ±pelvic LN using a risk-based method. Low-risk (LR) patients received 69.6Gy to only the prostate in 29 fractions. Intermediate- (IR) and high-risk (HR) patients received 30 fractions with 72Gy to the prostate, 54Gy to the SV, and 50.4Gy to the pelvic LN when risk of LN involvement exceeded 15% by the Roach formula. IR and HR patients received androgen deprivation therapy. Acute and late genitourinary (GU) and gastrointestinal (GI) toxicity were prospectively evaluated with patient and physician reported surveys.ResultsFifty-five men were enrolled and 49 had at least one year of follow up with 19.2% LR, 40.4% IR, and 40.4% HR disease. The median age was 69years and median follow-up time was 36.9months. Twenty-six patients received pelvic nodal HSIB-IMRT. At 2years, the cumulative incidence of physician-reported late grade 2+ GU and GI toxicity were 32.6%, and 18.4% respectively. At 2-years, only 10.2% grade 2+ GU toxicities and 2.0% grade 2+ GI toxicities remained unresolved. At last follow up, the prevalence of unresolved physician-reported late grade 2+ GU and GI toxicity was 4.1% and 0%. The median patient-reported AUA-IPSS score fell from 10 at baseline to 7.5 at 2years. The 3-year biochemical relapse-free survival rate for the cohort was 96%.ConclusionsHSIB-IMRT with risk-based nodal coverage results in excellent biochemical control. While the cumulative incidence of physician-reported GU toxicity was higher than anticipated, late GI and GU toxicity was relatively transient.



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