An Evaluation of Prostate Volume and Proton Therapy-Related Toxicities Libby Krcik, BS, RT(T), Patrick Lee, MS, RT(T), CMD, Mingcheng Gao, PhD, Mark Pankuch, PhD, Megan Boroczk, BS, William Hartsell, MD Northwestern Medicine Chicago Proton Center

Purpose To analyze trends in the occurrence rate and severity of patient reported adverse proton beam therapy toxicities as a function of prostate size for low and intermediate risk prostate cancer patients. In other words: Does a larger prostate cause higher grade toxicities?

Background The severity of symptoms from benign prostatic hyperplasia (BPH) does not correlate with the degree of hyperplasia1 The prevalence of gross hematuria in patients with BPH is unknown2-4 Other urinary tract conditions can cause similar symptoms1 We got information leaning towards the hypothesis that the size of a prostate does not really correlate to the degree of hematuria in patients who even get that symptom. Part of the reason we wanted to find out if prostate size correlates to toxicities in patients receiving proton therapy, more specifically hematuria. 1. Edwards JL. Am Fam Physician. 2015. 2. Kearny MC, Bingham JB, Bergland R, Mead-D’Alisera P, Puchner, PJ. The Journal of Urology. 2002. 3. Foley SJ et al. The Journal of Urology. 2000. 4. Foley SJ. The Prostate Journal. 2000.

Methods Prospective collection of data for 688 prostate cancer patients Proton Collaborative Group (PCG) registry study 70.0 Gy at 2.5 Gy per fx, OR 79.2 Gy at 1.8 Gy per fx Prostate size defined by MRI Collected at a single institution from October 2010 to October 2016 All patients were enrolled in PCG and treated with definitive proton therapy to the intact prostate Took out patients who received pelvic nodal irradiation MRI found in patient’s EMR, a handful were found from ultrasound biopsy reports

Methods Continued < 25 76 26-50 418 51-75 155 76-100 43 > 100 22 Prostate Size (cc) Patient Total < 25 76 26-50 418 51-75 155 76-100 43 > 100 22 Patients divided into 5 groups Median follow up of 2.03 years Genitourinary, gastrointestinal, and dermatological toxicities collected Pearson chi-square test performed Median follow up of 2.3 years= most recent follow up minus the day of last tx ranged from 5.95 years to 0.31 years Frequency of each toxicity grade was calculated for each prostate size group in a percentage P-value calculated for significance of our findings

Gastrointestinal Results No significant trends in gastrointestinal or dermatological toxicities -Very very few grade 3 occurrences of any GI side effects

Dermatological Results Shows no correlation based on prostate volume -Almost all patients had grade 1 dermatitis, low instances of grade 2 but follows no pattern

Genitourinary Results Notable increases in grade 1 and 2 hematuria with increasing prostate size Very few high grade toxicities overall Grade 1 Grade 2 Grade 3 Asymptomatic; clinical or diagnostic observations only; intervention not indicated Symptomatic; urinary catheter or bladder irrigation indicated; limiting instrumental ADL Gross hematuria; transfusion, IV medications or hospitalization indicated; elective endoscopic, radiologic or operative intervention indicated; limiting self care ADL Hardly any toxicities exceeded Grade 2 CT-CAE Definitions

Prostate Size and Hematuria Correlation Grade 1 p-value= .019 Grade 2 p-value= .006 Smaller prostate sizes (25-75) experienced about 9-11.7% grade 1 toxicity AND 0-2.6% grade 2 toxicity Larger prostate volume sizes (75-100cc and greater) reported grade 1 toxicities of 20.9-27.3% A fairly large increase in incidence AND grade 2 toxicities of about 4.7% Point out 1 occurrence of Grade 3 in 25-50 range

Conclusion Most proton therapy-related toxicities exhibited no significant relationship to prostate volume Significant correlation between prostate size and incidence of low grade hematuria Low severity of symptoms in patients treated with proton therapy irrespective of prostate size - The low occurrence rates of all grade 3 toxicities demonstrate a…

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