The value of Botox-A in acute radiation proctitis: results from a phase I/II study using a three-dimensional scoring system.
OBJECTIVE
Acute radiation proctitis (ARP) is a common side effect of pelvic radiotherapy, and its management is challenging in daily practice. The present phase I/II study evaluates the safety and efficacy of the botulinum toxin A (BTX-A) in ARP treatment for rectal cancer patients undergoing neoadjuvant high-dose-rate endorectal brachytherapy (HDREBT).


METHODS
Fifteen patients, treated with neoadjuvant HDREBT, 26-Gy in 4 fractions, received the study treatment that consisted of a single injection of BTX-A into the rectal wall. The injection was performed post-HDREBT and prior to the development of ARP. The control group, 20 such patients, did not receive the BTX-A injection. Both groups had access to standard treatment with hydrocortisone rectal aerosol foam (Cortifoam) and anti-inflammatory and narcotic medication. The ARP was clinically evaluated by self-administered daily questionnaires using visual analog scores to document frequency and urgency of bowel movements, rectal burning/tenesmus, and pain symptoms before and after HDREBT.


RESULTS
At the time of this analysis, there was no observed systemic toxicity. Patient compliance with the self-administered questionnaire was 100% from week 1 to 4, 70% during week 5, and 40% during week 6. The maximum tolerated dose was established at the 100-U dose level, and noticeable mean differences were observed in bowel frequency (p = 0.016), urgency (p = 0.007), and pain (p = 0.078).


CONCLUSIONS
This study confirms the feasibility and efficacy of BTX-A intervention at 100-U dose level for study patients compared to control patients. A phase III study with this dose level is planned to validate these results.
Vuong
Te
T
Department of Radiation Oncology, McGill University, Montréal, Canada. tvuong@jgh.mcgill.ca
Waschke
Kevin
K
Niazi
Tamim
T
Richard
Carole
C
Parent
Josee
J
Liberman
Sender
S
Mayrand
Serge
S
Loungnarath
Rasmy
R
Stein
Barry
B
Devic
Slobodan
S
D000893:Anti-Inflammatory Agents / Q000008:administration & dosage*; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage*; D001918:Brachytherapy / Q000009:adverse effects* / Q000379:methods; D016022:Case-Control Studies; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000008:administration & dosage; D008297:Male; D020714:Maximum Tolerated Dose; D011349:Proctitis / Q000188:drug therapy*; D011832:Radiation Injuries / Q000188:drug therapy*; D012004:Rectal Neoplasms / Q000532:radiotherapy*; D011795:Surveys and Questionnaires
D000893:Anti-Inflammatory Agents; D019274:Botulinum Toxins, Type A; D006854:Hydrocortisone