Moderately Hypofractionated Intensity Modulated Radiation Therapy With Simultaneous Integrated Boost for Prostate Cancer: Five-Year Toxicity Results From a Prospective Phase I/II Trial.

BACKGROUND: In this phase I/II trial, 5-year physician-assessed toxicity and patient reported quality of life data is reported for patients undergoing moderately hypofractionated intensity modulated radiation therapy (IMRT) for prostate cancer using a simultaneous integrated boost (SIB) and pelvic lymph node (LN) coverage. MATERIALS AND METHODS: Patients with T1-T2 localized prostate cancer were prospectively enrolled, receiving risk group based coverage of prostate ± seminal vesicles (SVs) ± pelvic lymph nodes (LNs). Low risk (LR) received 69.6 Gy/29 fractions to the prostate, while intermediate risk (IR) and high risk (HR) patients received 72 Gy/30fx to the prostate and 54Gy/30fx to the SVs. If predicted risk of LN involvement >15%, 50.4 Gy/30fx was delivered to pelvic LNs. Androgen deprivation therapy was given to IR and HR patients. RESULTS: There were 55 patients enrolled and 49 patients evaluable at a median follow up of 60 months. Included were 11 (20%) LR, 23 (41.8%) IR, and 21 (38.2%) HR patients. Pelvic LN treatment was given in 25 patients (51%). Prevalence rates of late grade 2 GI toxicity at 1, 3, and 5 years was 5.8, 3.9, and 5.8%, respectively, with no permanent grade 3 events. Prevalence rates of late grade 2 GU toxicity at 1, 3, and 5 years rates were 15.4, 7.7, and 13.5%, respectively, with three grade 3 events (5.8%). The biochemical relapse free survival at 5 years was 88.3%. There were no local, regional, or distant failures, with all patients still alive at last follow up. CONCLUSION: Moderate hypofractionation of localized prostate cancer utilizing a SIB technique and LN coverage produces tolerable acute/late toxicity. Given equivalent efficacy between moderate hypofractionation schedules, the optimal regimen will be determined by long-term toxicity reported from both the physician and patient perspective. CLINICAL TRIAL REGISTRATION: www.ClinicalTrials.gov, identifier NCT01117935, Date of Registration: 5/6/2010.

Phase 1/2 study of hypofractionated intensity-modulated radiation therapy for prostate cancer including simultaneously integrated boost.

PURPOSE: This study evaluates the safety and efficacy of moderately hypofractionated radiation therapy (RT) with simultaneous integrated boost (HSIB) intensity modulated RT (IMRT) that includes coverage of the seminal vesicles (SVs) and pelvic lymph nodes (LNs). METHODS AND MATERIALS: Men with localized prostate cancer were prospectively enrolled in a phase 1/2 trial to receive HSIB-IMRT to the prostate, ± SV, ± pelvic LN using a risk-based method. Low-risk patients received 69.6 Gy to only the prostate in 29 fractions. Intermediate-risk (IR) and high-risk (HR) patients received 30 fractions with 72 Gy to the prostate, 54 Gy to the SV, and 50.4 Gy 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. RESULTS: Fifty-five men were enrolled, and 49 had at least 1 year of follow-up with 19.2% low-risk, 40.4% IR, and 40.4% HR disease. The median age was 69 years; median follow-up time was 36.9 months. Twenty-six patients received pelvic nodal HSIB-IMRT. At 2 years, the cumulative incidence of physician-reported late grade 2+ GU and GI toxicity was 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 American Urologic Association-International Prostate Symptom Score fell from 10 at baseline to 7.5 at 2 years. The 3-year biochemical relapse-free survival rate for the cohort was 96%. CONCLUSIONS: HSIB-IMRT with risk-based nodal coverage results in excellent biochemical control. Although the cumulative incidence of physician-reported GU toxicity was higher than anticipated, late GI and GU toxicity was relatively transient.

A Phase II Study to Prevent Radiation-induced Rectal Injury With Lovastatin.

PURPOSE: Physician reported symptomatic late rectal injury occurs in about 5% to 25% of patients treated with radiation therapy for prostate cancer, depending on the treatment technique. Patients, however, report clinically meaningful declines in bowel/rectal function regardless of the technique used. Lovastatin has been shown to protect mice from late radiation injury. This study was designed to determine if lovastatin might reduce the incidence of late rectal injury in patients receiving radiation therapy for prostate cancer. MATERIALS AND METHODS: Patients with adenocarcinoma of the prostate receiving radiotherapy with curative intent were eligible. A portion of the rectum had to receive at least 60 Gy. Gastrointestinal functioning was assessed using both physician-reported and patient-reported instruments at baseline and at prescribed intervals during and after treatment. Lovastatin (20 to 80 mg/d) was started on day 1 of radiation and continued for 12 months. Patients were followed for an additional 12 months. The primary endpoint was physician-reported rectal toxicity ≥grade 2 during the first 2 years after treatment. RESULTS: A total of 20/53 (38%) patients developed grade 2 or higher toxicity during the 2-year follow-up period. Seventeen patients had 1 or more unresolved gastrointestinal symptom at the end of 2 years, 3 (6%) of which were grade 2 and none were of higher grade. CONCLUSIONS: The primary endpoint of the study was not met. Lovastatin, as administered in this trial, did not reduce the incidence of grade 2 or higher rectal toxicity compared with historical controls.