Health-Related Quality of Life and Toxicity After Definitive High-Dose-Rate Brachytherapy Among Veterans With Prostate Cancer.

PURPOSE: High-dose-rate (HDR) brachytherapy (BT) is a well-tolerated and effective treatment for prostate cancer. There is limited research, however, investigating toxicity outcomes with HDRBT treatment among veterans. The objective of this study is to assess the impact on health-related quality of life (hrQOL) and physician-graded toxicities associated with HDRBT as monotherapy among veterans treated at Edward Hines, Jr. Veterans Affairs Hospital in Hines, Illinois. METHODS: Between 2016 and 2019, 74 veterans with low- or intermediate-risk prostate cancer were treated with HDRBT as monotherapy with 27 Gy in 2 fractions, delivered over 2 implants. Veteran-reported hrQOL in the genitourinary (GU), gastrointestinal (GI), and sexual domains was assessed using the International Prostate Symptoms Score (IPSS) and Expanded Prostate Cancer Index Composite (EPIC-26) questionnaire. Mixed linear effect models were used to assess differences in the hrQOL scores at follow-up compared with baseline scores. Statistically significant differences in hrQOL scores from baseline were further assessed for clinical significance, using minimal clinically important difference (MCID) evaluations. RESULTS: Median follow-up was 18 months. Veterans reported declines in GU, GI, and sexual hrQOL scores immediately after treatment, with the IPSS and EPIC-26 hrQOL scores all displaying significant decrease from baseline over time. The majority of the declines in hrQOL scores met criteria for MCID. These hrQOL scores trended toward a return to baseline, with the EPIC-26 urinary obstruction score returning to baseline at the 18-month follow-up assessment and the EPIC-26 bowel score returning to baseline at the 12-month follow-up. The IPSS, urinary incontinence, and sexual scores did not return to baseline at 18 months. The grade 2 maximum physician-graded GU, GI, and sexual toxicity rates were 65%, 5%, and 53%, respectively. There was 1 incidence of grade 3 GU toxicity but no grade 3 GI or sexual toxicity. CONCLUSIONS: HDRBT as monotherapy is a well-tolerated treatment option for veterans with low- or intermediate-risk prostate cancer, with favorable veteran-reported and physician-graded toxicities. Veterans should be educated about HDRBT as an option when counseled regarding treatment for localized prostate cancer.

Computed tomography versus magnetic resonance imaging in high-dose-rate prostate brachytherapy planning: The impact on patient-reported health-related quality of life.

PURPOSE: High-dose-rate (HDR) prostate brachytherapy uses volumetric imaging for treatment planning. Our institution transitioned from computed tomography (CT)-based planning to MRI-based planning with the hypothesis that improved visualization could reduce treatment-related toxicity. This study aimed to compare the patient-reported health-related quality of life (hrQOL) and physician-graded toxicity outcomes of CT-based and MRI-based HDR prostate brachytherapy. METHODS: From 2016 to 2019, 122 patients with low- or intermediate-risk prostate cancer were treated with HDR brachytherapy as monotherapy. Patients underwent CT only or CT and MRI imaging for treatment planning and were grouped per treatment planning imaging modality. Patient-reported hrQOL in the genitourinary (GU), gastrointestinal (GI), and sexual domains was assessed using International Prostate Symptom Score and Expanded Prostate Cancer Index Composite Short Form-26 questionnaires. Baseline characteristics, changes in hrQOL scores, and physician-graded toxicities were compared between groups. RESULTS: The median follow-up was 18 months. Patient-reported GU, GI, and sexual scores worsened after treatment but returned toward baseline over time. The CT cohort had a lower baseline mean International Prostate Symptom Score (5.8 vs. 7.8, p = 0.03). The other patient-reported GU and GI scores did not differ between groups. Overall, sexual scores were similar between the CT and MRI cohorts (p = 0.08) but favored the MRI cohort at later follow-up with a smaller decrease in Expanded Prostate Cancer Index Composite Short Form-26 sexual score from baseline at 18 months (4.9 vs. 19.8, p = 0.05). Maximum physician-graded GU, GI, and sexual toxicity rates of grade ≥2 were 68%, 3%, and 53%, respectively, with no difference between the cohorts (p = 0.31). CONCLUSION: Our study shows that CT- and MRI-based HDR brachytherapy results in similar rates of GU and GI toxicity. MRI-based planning may result in improved erectile function recovery compared with CT-based planning.

Acid-Base Control of Valency within Carboranedithiol Self-Assembled Monolayers: Molecules Do the Can-Can.

We use simple acid-base chemistry to control the valency in self-assembled monolayers of two different carboranedithiol isomers on Au{111}. Monolayer formation proceeds via Au-S bonding, where manipulation of pH prior to or during deposition enables the assembly of dithiolate species, monothiol/monothiolate species, or combination. Scanning tunneling microscopy (STM) images identify two distinct binding modes in each unmodified monolayer, where simultaneous spectroscopic imaging confirms different dipole offsets for each binding mode. Density functional theory calculations and STM image simulations yield detailed understanding of molecular chemisorption modes and their relation with the STM images, including inverted contrast with respect to the geometric differences found for one isomer. Deposition conditions are modified with controlled equivalents of either acid or base, where the coordination of the molecules in the monolayers is controlled by protonating or deprotonating the second thiol/thiolate on each molecule. This control can be exercised during deposition to change the valency of the molecules in the monolayers, a process that we affectionately refer to as the "can-can." This control enables us to vary the density of molecule-substrate bonds by a factor of 2 without changing the molecular density of the monolayer.