1. Rectal toxicity for patients treated with proton beam radiation diagnosed with prostate cancer using free rectal water, water filled rectal balloon or interstitial Hydrogel for rectal immobilization
Victoria Casablanca B.S.R.T (T), Staff Radiation Therapist Northwestern Medicine Chicago Proton Center
Welcome. Thank you for joining me today. This talk is on Rectal toxicity for patients treated with Proton beam radiation.
I do not have any disclosures to report today.
In this talk I will be covering the method of our research, the background of our research, and the results of our research as well as what is next for this research.

2. Purpose of this Research
Why is this study being done… to improve effectiveness of treatments and procedures
Hypothesis of this study…lower grade rectal toxicities in treatments using Hydrogel
What was studied…treatments from November 2010 to March 2017
The purpose of this study was to collect and analyze information from individuals with a similar diagnosis.
Ultimately, the goal is to improve effectiveness of treatments and procedures and limit side effects and late complications for patients.
Multiple techniques are used to decrease the rectal dose and improve internal immobilization for treatment of prostate cancer. We hypothesized that patients with an implanted biodegradable tissue expander would have lower grade rectal toxicities than the alternatives (rectal fill of free water or rectal balloon).
In this study we looked at three types of rectal immobilization in comparison with grades of rectal toxicities. This was a retrospective study ranging from treatments in November 2010 to March Over this time frame the type of rectal immobilization has adapted with newer technologies.

3. Background
Free Rectal Water Rectal Balloon Implanted Tissue Expander (Hydrogel)
Photo taken of Radiadyne ImmobiLoc rectal balloon.
In 2011 at the proton center we were filling rectums with free water using 100ccs inserted into the rectum prior to treatment.
Around 2012 we introduced the rectal balloon, pictured here.

4. Hydrogel Position Normal Anatomy Implanted Spacer On average 1 cm of
Beginning in 2015 Hydrogel
Gel spacer injected through the perineal wall to minimize dose to rectum
Persistence: lasts about 3 months
Absorbs: Within approx 6 months
Currently the majority of our patients are treated using an implanted tissue expander called Hydrogel pictured here
Hydrogel creates on average, 1cm of space between prostate and rectum

5. Method of Research
2941
1028
308
309
220
837
Number of patients researched
based on time constraints*
Total number of patients
on Registry Study
Free Water
Total number of patients
diagnosed with Prostate Cancer
Balloon
Research conditions:
Since the submission of the abstract these numbers and results have been updated.
Prospective collection of data through the prostate registry from a single institution with Proton Collaborative Group from November 2010 to March Most were treated with daily fractionated proton radiation therapy to 79.2 Cobalt Gray Equivalents (CGE) in 1.8 CGE fractions. Three consecutive cohorts of patients were treated, first with free rectal water (308 patients), then with rectal balloons (309 patients) and most recently with an interstitial hydrogel (220 patients). We evaluated GI toxicities (proctitis, fecal incontinence, diarrhea, and rectal hemorrhage) for each of the three techniques.
1028 of the 2941 patients on registry study were diagnosed and treated for prostate cancer.
We chose a smaller randomized sample size for each rectal fill totally to 837 patients researched.
Free water 308 number of patients
Rectal balloon 309 number of patients
Hydrogel 221 number of patients
* As well as time constraints there were a handful of patients whom were removed from the research. These patients were recorded as having no rectal fill for treatment.
Toxicities
-Grade 1-3
proctitis, fecal incontinence, diarrhea, and rectal hemorrhage
Registry Study … Proton Collaborative Group from a single institution November 2010 to March 2017
Hydrogel

6. Toxicity Defined Gastrointestinal Disorders Diarrhea
Adapted from CTCEA v4.0
Gastrointestinal Disorders
Diarrhea
Grade 1: Increase of <4 stools per day over baseline; mild increase in ostomy output compared to baseline
Grade 2: Increase of stools per day over baseline; moderate increase in ostomy output compared to baseline
Grade 3: Increase of >=7 stools per day over baseline; incontinence; hospitalization indicated; severe increase in ostomy output compared to baseline; limiting self care ADL
Fecal Incontinence
Grade 1: Occasional use of pads required
Grade 2: Daily use of pads required
Grade 3: Severe symptoms; elective operative intervention indicated
Proctitis
Grade 1: Rectal discomfort, intervention not indicated
Grade 2: Symptoms (e.g., rectal discomfort, passing blood or mucus); medical intervention indicated; limiting instrumental ADL
Grade 3: Severe symptoms; fecal urgency or stool incontinence; limiting self care ADL
Rectal Hemorrhage
Grade 1: Mild; intervention not indicated
Grade 2: Moderate symptoms; medical intervention or minor cauterization indicated
Grade 3: Transfusion, radiologic, endoscopic, or elective operative intervention indicated
Diarrhea term by CTCAE v4.0: A disorder characterized by frequent and watery bowel movements.
Fecal Incontinence term: A disorder characterized by inability to control the escape of stool from the rectum.
Proctitis term: A disorder characterized by inflammation of the rectum.
Rectal Hemorrgage term: A disorder characterized by bleeding from the retroperitoneal area.
Activites of Daily Living: ADL

7. Results

8. Results
Rectal Fill
Total Patients
Grade 0
Grade 1
Grade 2
Grade 3
Total Adverse Events
Free Water
308
116
143 49
192
Balloon
309 90
156 60 3
219
Hydrogel
220
142 68 11 1 80
Grade 3 GI toxicities were rare, occurring in only 4/837 patients (0.48%).
Grade 2 toxicities were more common in patients treated with free water (49/308) or rectal balloon (60/309) than with hydrogel (11/220).
A significantly larger portion of hydrogel patients experienced no GI toxicity (Grade 0 – 142/220) compared to free water (116/308) or rectal balloon (90/309).
CONCLUSION: The incidence of >Grade 1 rectal toxicity is noticably lower in patients who are treated with an implanted biodegradable hydrogel expander, compared to prior techniques of rectal immobilization.

9. Results
This slide show cases the percentage of patients that reported a toxicity in the respective group based on rectal fill.
As denoted with the green color bar for Hydrogel it is noted that when appropriate it is smaller than the other two rectal fills for grade In Grade 0 or no reported toxicity it is a larger percentage of patients.

10. Conclusion Analysis is ongoing at this time.
Initial results show improved rectal toxicity for patients treated with a rectal fill of Hydrogel in comparison to those treated with rectal fill of free water or balloon.
Continued collection of data through the registry study at a single institution, Northwestern Medicine Chicago Proton Center, through the Proton Collaborative Group.
Special thank you
I would like to give a special thanks to those that worked diligently on this research study.
Rebecca Price, who put in the long hours and nights gathering data.
Megan our Clinical research coordinator
Dr. William Hartsell
Northwestern Medicine and the patients who allowed us the opportunity to analyze their treatment to better understand for the future.

11. Questions?