Stereotactic body radiotherapy with periprostatic hydrogel spacer for localized prostate cancer: toxicity profile and early oncologic outcomes.

BACKGROUND: Multiple phase I-II clinical trials have reported on the efficacy and safety of prostate stereotactic body radiotherapy (SBRT) for the treatment of prostate cancer. However, few have reported outcomes for prostate SBRT using periprostatic hydrogel spacer (SpaceOAR; Augmenix). Herein, we report safety and efficacy outcomes from our institutional prostate SBRT experience with SpaceOAR placement. METHODS: Fifty men with low- or intermediate-risk prostate cancer treated at a single institution with linear accelerator-based SBRT to 3625 cGy in 5 fractions, with or without androgen deprivation therapy (ADT) were included. All patients underwent SpaceOAR and fiducial marker placement followed by pre-treatment MRI. Toxicity assessments were conducted at least weekly while on treatment, 1 month after treatment, and every follow-up visit thereafter. Post-treatment PSA measurements were obtained 4 months after SBRT, followed by every 3-6 months thereafter. Acute toxicity was documented per RTOG criteria. RESULTS: Median follow up time was 20 (range 4-44) months. Median PSA at time of diagnosis was 7.4 (2.7-19.5) ng/ml. Eighteen men received 6 months of ADT for unfavorable intermediate risk disease. No PSA failures were recorded. Median PSA was 0.9 ng/mL at 20 months; 0.08 and 1.32 ng/mL in men who did and did not receive ADT, respectively. Mean prostate-rectum separation achieved with SpaceOAR was 9.6 ± 4 mm at the prostate midgland. No grade ≥ 3 GU or GI toxicity was recorded. During treatment, 30% of men developed new grade 2 GU toxicity (urgency or dysuria). These symptoms were present in 30% of men at 1 month and in 12% of men at 1 year post-treatment. During treatment, GI toxicity was limited to grade 1 symptoms (16%), although 4% of men developed grade 2 symptoms during the first 4 weeks after SBRT. All GI symptoms were resolving by the 1 month post-treatment assessment and no acute or late rectal toxicity was reported > 1 month after treatment. CONCLUSIONS: Periprostatic hydrogel placement followed by prostate SBRT resulted in minimal GI toxicity, and favorable early oncologic outcomes. These results indicate that SBRT with periprostatic spacer is a well-tolerated, safe, and convenient treatment option for localized prostate cancer.

Travel distance and stereotactic body radiotherapy for localized prostate cancer.

BACKGROUND: Definitive stereotactic body radiotherapy (SBRT) represents an emerging and debated treatment option for patients with prostate cancer, with potential economic savings and reports of short-term efficacy since 2006. The current study sought to define national trends in definitive prostate SBRT use and determine whether patterns vary by travel distance for treatment. METHODS: The National Cancer Data Base identified 181,544 men with localized prostate cancer who were treated with definitive external beam radiotherapy from 2004 through 2012. Joinpoint regression analyzed definitive prostate SBRT trends over time, whereas multivariable logistic regression defined the odds for its receipt by travel distance for treatment. RESULTS: Definitive prostate SBRT use increased from 1.8% in 2004 to 5.9% in 2012 (P for trend <.0001), with a joinpoint for increased use noted in 2006 (P<.0001). Higher SBRT use was found to be associated with longer travel distance for treatment, younger age, white race, more affluent zip code of residence, academic treatment center, favorable disease characteristics, and fewer comorbidities (all P<.0001). Compared with travel distances <25 miles for treatment, travel distances of 25 to 50 miles and >50 miles were associated with increasing adjusted odds of receipt of definitive prostate SBRT (1.63 [95% confidence interval, 1.51-1.76] and 2.35 [95% confidence interval, 2.14-2.57], respectively; both P < .0001). CONCLUSIONS: Definitive prostate SBRT use increased more than 3-fold since 2004, with a significant increase in use coinciding with early reports of short-term efficacy. Long-distance travel for treatment was associated with greater than twice the odds of receipt of definitive prostate SBRT compared with short-distance travel, suggesting that treatment decisions with unknown long-term clinical implications may be strongly driven by sociodemographic factors. Cancer 2018;124:1141-9. © 2017 American Cancer Society.

A side-by-side comparison of T cell reactivity to fifty-nine Mycobacterium tuberculosis antigens in diverse populations from five continents.

We compared T cell recognition of 59 prevalently recognized Mycobacterium tuberculosis (MTB) antigens in individuals latently infected with MTB (LTBI), and uninfected individuals with previous BCG vaccination, from nine locations and populations with different HLA distribution, MTB exposure rates, and standards of TB care. This comparison revealed similar response magnitudes in diverse LTBI and BCG-vaccinated cohorts and significant correlation between responses in LTBIs from the USA and other locations. Many antigens were uniformly recognized, suggesting suitability for inclusion in vaccines targeting diverse populations. Several antigens were similarly immunodominant in LTBI and BCG cohorts, suggesting applicability for vaccines aimed at boosting BCG responses. The panel of MTB antigens will be valuable for characterizing MTB-specific CD4 T cell responses irrespective of ethnicity, infecting MTB strains and BCG vaccination status. Our results illustrate how a comparative analysis can provide insight into the relative immunogenicity of existing and novel vaccine candidates in LTBIs.