Olfactory Perception During Proton Radiation and Differences in Frequency of Olfactory Perceptions Based on Proton Craniospinal Irradiation Technique for Pediatric Brain Tumor Patients

Committee/Faculty

Presenting Author(s)

Mi

Myrsini ioakeim-ioannidou, n/a

MD
Massachusetts General Hospital
Boston, Massachusetts, United States

Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.

Co-Author(s)

PE

Parsa Erfani

Medical Student
Harvard Medical School
Boston, Massachusetts, United States

Disclosure: Disclosure information not submitted.
TU

Tobias Urell

Student intern
Massachusetts General Hospital
Boston, Massachusetts, United States

Disclosure: Disclosure information not submitted.
JD

Juliane Daartz

Medical Physicist
Massachusetts General Hospital
Boston, Massachusetts, United States

Disclosure: Disclosure information not submitted.
JB

Julia Berv

Physician Assitant
Massachusetts General Hospital
Boston, Massachusetts, United States

Disclosure: Disclosure information not submitted.
SL

Shannon Leahy

US technician
Massachusetts General Hospital
Boston, Massachusetts, United States

Disclosure: Disclosure information not submitted.
BF

Barbara Fullerton

Assistant Professor of Otolaryngology–Head and Neck Surgery, Harvard Medical School
Massachusetts General Hospital
Boston, Massachusetts, United States

Disclosure: Disclosure information not submitted.
RB

Rachel Bolton

RN
Massachusetts General Hospital
Boston, Massachusetts, United States

Disclosure: Disclosure information not submitted.
TY

Torunn Yock, n/a

MD, MCH
Massachusetts General Hospital
Boston, Massachusetts, United States

Disclosure: Disclosure information not submitted.
NT

Nancy Tarbell

MD
Massachusetts General Hospital
Boston, Massachusetts, United States

Disclosure: Disclosure information not submitted.
Shannon MacDonald, MD

MD
Massachusetts General Hospital
Boston, Massachusetts, United States

Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.

Purpose:

Background: Unusual olfactory perception has been reported during brain radiation treatments but is infrequent and does not typically interfere with the ability to deliver treatment or cause notable distress.

Aim: To report rates of olfactory perception for proton craniospinal irradiation (CSI).
To determine if olfactory perceptions are greater for pencil beam scanning technique (PBS) technique compared to 3D-CRT and if olfactory perceptions are greater for a single field PBS treatment versus a two-field PBS treatment. To determine if nausea/vomiting is greater for PBS technique compared to 3D-CRT and if those symptoms are greater for a single field PBS technique compared to a two-field PBS technique.

Methodology: We performed a retrospective review of 127 pediatric patients treated with proton radiation therapy (PRT) for primary brain tumors in a single institution between 2016-2021. Patients received PRT to the brain as part of craniospinal irradiation (CSI) followed by a boost to the brain. Proton CSI was delivered with 3D-CRT protons (n=53) or PBS (n=74). Within the PBS group, treatment delivery to the CSI utilized a single PA field (n=24) or two posterior oblique fields (n=50). We collected data on abnormal olfactory sensations, nausea/vomiting, and the use of medical intervention for those symptoms.

Results: Our cohort included 80 males and 47 females. The median age of patients was 10 years old (range, 3 – 21). Seventy-one patients received concurrent chemotherapy. Prior to PRT, 31 patients were nauseous. During the radiation course, 104 patients developed worsening nausea while 63 patients reported episodes of emesis. Four patients vomited while receiving radiation. Seventeen patients reported olfactory perceptions during CSI. We found a higher rate of olfactory perception in patients treated with PBS (n=16, 22%) than 3D-CRT (n=1, 2%) (p=0.001) and, within the PBS group, patients treated with a single PA field (n=11, 46%) than two oblique fields (n=5, 10%) (p=0.002). Seventy-eight patients required intervention including addition of anti-emetic or anti-anxiety medication. Two patients required sedation due to the malodorous smell during CSI. We did not find any significant difference in nausea/vomiting based on treatment technique.

Conclusions: PBS and PBS technique influence olfactory perceptions but not the occurrence of the rate of nausea/vomiting. Further studies should be performed to validate these findings and determine techniques to minimize unpleasant olfactory perceptions.

References: