Prospective evaluation of patient-reported outcomes of invisible ink tattoos for the delivery of external beam radiation therapy: the PREFER trial

Abstract

Introduction: Invisible ink tattoos (IITs) avoid cosmetic permanence of visible ink tattoos (VITs) while serving as more reliable landmarks for radiation setup than tattooless setups. This trial evaluated patient-reported preference and feasibility of IIT implementation.

Methods and materials: In an IRB-approved, single institution, prospective trial, patients receiving proton therapy underwent IIT-based treatment setup. A survey tool assessed patient preference on tattoos using a Likert scale. Matched patients treated using our institutional standard tattooless setup were identified; treatment times and image guidance requirements were evaluated between tattooless and IIT-based alignment approaches. Distribution differences were estimated using Wilcoxon rank-sum tests or Chi-square tests.

Results: Of 94 eligible patients enrolled, median age was 58 years, and 58.5% were female. Most common treatment sites were breast (18.1%), lung (17.0%) and pelvic (14.9%). Patients preferred to receive IITs versus VITs (79.8% pre-treatment and 75.5% post-treatment, respectively). Patients were willing to travel farther from home to avoid VITs versus IITs (p<0.01). Females were willing to travel (45.5% vs. 23.1%; p=0.04) and pay additional money to avoid VITs (34.5% vs. 5.1%; p<0.01). Per-fraction average +treatment time and time from on table/in room to first beam were shorter with IIT-based vs. tattooless setup (12.3min vs. 14.1min; p=0.04 and 24.1min vs. 26.2min; p=0.02, respectively).

Discussion: In the largest prospective trial on IIT-based radiotherapy setup to date, we found that patients prefer IITs to VITs. Additionally, IIT-based alignment is an effective and efficient strategy in comparison with tattooless setup. Standard incorporation of IITs for patient setup should be strongly considered.

Keywords: image guided radiotherapy; proton therapy; quality of life; radiation tattoos; radiation therapy.

Figure 1

Representative photos of administered Invisible Ink Tattoos (IITs). (A–C) IIT under fluorescent light administered in patients with lower (A, B) and higher (C) baseline skin pigmentation. (D–F) IIT under blacklight flashlight in patients with lower (D, E) and higher (F) baseline skin pigmentation. Blue circles denote IIT location.

Figure 2

End of treatment questionnaire responses (N=94). (A) Three survey questions with responses: I would prefer not to have received tattoos, even though they are invisible and they help to ensure proper alignment to optimize proton therapy; Receiving invisible tattoos was painful; Receiving invisible tattoos was time consuming (Red = Agree; Green = Neutral; Blue = Disagree). (B) One survey question with response: The primary reason why I would prefer not to have received tattoos is X (Red = Emotional Distress; Green = Pain of Tattoo Placement; Blue = Visibility/Aesthetics; Purple = Other). (C) One survey question with response: My level of satisfaction with the appearance of the areas tattooed is X (Red = Satisfied; Green = Neutral; Blue = Dissatisfied). (D) One survey question with response: How would you rate the overall cosmetic outcome of the areas of invisible tattoo mark placement? (Red = Excellent; Green = Good; Blue = Fair; Purple = Poor). (E) One survey question with response: How visible are the tattoo marks? (Red = Very visible; Green = Faintly visible; Blue = Not visible; Purple = Other).