Early toxicity and patient reported quality-of-life in patients receiving proton therapy for localized prostate cancer: a single institutional review of prospectively recorded outcomes

• Main Authors: Howard J. Lee, Meghan W. Macomber, Matthew B. Spraker, Stephen R. Bowen, Daniel S. Hippe, Angela Fung, Kenneth J. Russell, George E. Laramore, Ramesh Rengan, Jay Liao, Smith Apisarnthanarax, Jing Zeng
• Format: Article
• Language: English
• Published: BMC 2018-09-01
• Series: Radiation Oncology
• Subjects: Prostate cancer; Proton therapy; Quality of life; Patient reported outcomes
• Online Access: http://link.springer.com/article/10.1186/s13014-018-1127-6

Abstract Background We report prospectively captured clinical toxicity and patient reported outcomes in a single institutional cohort of patients treated for prostate cancer with proton beam therapy (PBT). This is the largest reported series of patients treated mostly with pencil beam scanning PBT. Methods We reviewed 231 patients treated on an IRB approved institutional registry from 2013 to 2016; final analysis included 192 patients with > 1-year of follow-up. Toxicity incidence was prospectively captured and scored using CTCAE v4.0. International Prostate Symptoms Score (IPSS), Sexual Health Inventory for Men (SHIM) score, and Expanded Prostate Cancer Index Composite (EPIC) bowel domain questionnaires were collected at each visit. Univariate Cox regression was used to explore associations of grade 2+ toxicity with clinical, treatment, and dosimetric variables. Results Median follow-up was 1.7 years. Grade 3 toxicity was seen in 5/192 patients. No grade 4 or 5 toxicity was seen. Patient reported quality-of-life showed no change in urinary function post-radiation by IPSS scores. Median SHIM scores declined by 3.7 points at 1-year post-treatment without further decrease beyond year 1. On univariate analysis, only younger age (HR = 0.61, p = 0.022) was associated with decreased sexual toxicity. EPIC bowel domain scores declined from 96 at baseline (median) by an average of 5.4 points at 1-year post-treatment (95% CI: 2.5–8.2 points, p < 0.001), with no further decrease over time. Bowel toxicity was mostly in the form of transient rectal bleeding and was associated with anticoagulation use (HR = 3.45, p = 0.002). Conclusions Grade 3 or higher toxicity was rare at 2-years after treatment with PBT for localized prostate cancer. Longer follow-up is needed to further characterize late toxicity and biochemical control. Trial registration NCT, NCT01255748. Registered 1 January 2013.