2617 - Prospective Study of All Sensations Patients Experience While Proton or Photon External Beams Are on

S. Teplow¹, S. Chandrasekhar¹, and R. P. Ermoian²; ¹University of Washington, Seattle, WA, ²Department of Radiation Oncology, University of Washington/ Fred Hutchinson Cancer Center, Seattle, WA

Purpose/Objective(s): Prior studies show visual (Cherenkov light) and olfactory sensations can occur while radiation to head, neck, and brain is on. However, few studies examine a wider range of sensations and compare sensations experienced between photon and proton radiation. The present IRB-approved study evaluates the relationship between radiation site, radiation type, and sensation experienced. We hypothesized that the rates and qualities of sensations vary to treatment site and radiation modality. Materials/

Methods: Subjects were consentable English-speaking patients = 18 years old. During their radiation course, they completed a survey regarding the presence and quality of sensations. Type and anatomic site of radiation (proton or photon) was collected from medical records. Radiation site was categorized as head, neck, brain (HNB), other radiation site (ORS, which included thorax, breast, abdomen, pelvis and extremity), or total body (TBI). Sensation was categorized as visual, olfactory, skin, or other. Linear regressions were used to determine the respective relationships between radiation site and type with sensation. Chi squared analyses assessed differences in incidences of sensations between groups of patients.
Results: 201 subjects participated, including 96 proton patients, 84 non-TBI photon patients, and 21 TBI patients. 41% of subjects reported = 1 sensation, including 62% of HNB, 26% of TBI, and 60% of TBI. The HNB and TBI patients differed in the rates of visual sensations (45% vs 14%, p= 0.012), and skin/other sensations (25% vs 48%, p=0.046, but not in olfactory sensations (31% vs 14%, p= 0.18)). There was a significant relationship between radiation site and sensation (p <.001), with the odds of sensation during HNB and TBI radiation being 4.33 (95% CI [2.27 to 8.29]), and 3.61 (95% CI [1.39-9.41]), respectively, compared to ORS patients. There was also a significant relationship between type of radiation and sensation (p=0.035), with there being a 1.84 times higher odds of experiencing sensation during proton therapy than photon therapy (95% CI [1.04-3.04]).
Conclusion: Patients frequently experience sensations while external beam radiation is on, but the rates and types of sensations varied by site treated and modality of radiation. Radiation oncologists should counsel patients that they may experience these sensations.

Radiation Type	Sensation	Patients with sensations by treatment site (%)			P value
		HNB (N=65)	ORS (N=115)	TBI (N=21)
All (N=201)	Any (N=83)	40 (62)	31 (27)	12 (57)	>0.001
	Visual (N= 37)	29 (45)	5 (4)	3(14)	>0.001
	Olfactory (N= 26)	20 (31)	3 (3)	3 (14)	>0.001
	Skin + Other (N=51)	16 (25)	25 (22)	10 (48)	>0.042
Protons (N=96)	Any (N=47)	29 (64)	18 (35)	NA	0.004
	Visual (N=24)	22 (49)	2 (4)		>0.001
	Olfactory (N= 14)	12 (27)	2 (4)		0.002
	Skin + Other (N= 27)	12 (27)	15 (29)		NS
Photons (N=105)	Any (N= 36)	11 (55)	13 (20)	12 (57)	0.001
	Visual (N=13)	7 (35)	3 (5)	3(14)	0.002
	Olfactory (N=12)	8 (40)	1 (2)	3 (14)	>0.001
	Skin + Other (N=22)	2 (10)	10 (16)	10 (48)	0.003