Tattoo-Free Set-ups for Breast Cancer Patients Receiving Regional Nodal Irradiation: Evaluation of Accuracy and Time Efficiency.

PURPOSE/OBJECTIVE(S) Permanent skin-based tattoos have been considered in treatment planning an essential aspect of ensuring patient positioning accuracy for radiation delivery in breast cancer patients. Despite this benefit, tattoos may also be a reminder of cancer treatment long past the treatment itself, causing unnecessary emotional distress. With the advent of advanced imaging techniques, routine tattoo placement may no longer be necessary. We performed a retrospective study evaluating a tattoo-free method of set-up for breast cancer patients receiving RNI. MATERIALS/METHODS Following a transition in our institution's clinical practice toward a tattoo-free set-up in May 2020, we compared a cohort of breast cancer patients, in which tattoos were referenced for daily alignment ("tattoo group") and a second cohort in which tattoos were placed but not referenced for daily alignment ("no tattoo group"). The number of patients in the two groups were matched by tumor laterality (right versus left) and breath-hold utilization. Patients in both cohorts were positioned using surface-guided imaging with periodic megavoltage (MV) x-ray imaging to confirm patient positioning. The physical shifts obtained from MV imaging, after surface-imaging, and the duration of daily patient treatment were compared between the two cohorts using the Mann-Whitney U-test. RESULTS There were 14 patients in each cohort; 8 left-sided breath-hold patients and 6 right-sided non-breath-hold patients, for a total of 61 recorded duration times and shifts for the tattoo group and 59 recorded duration times and shifts for the no-tattoo group. The average physical 3-dimensional shifts for the no-tattoo group was smaller compared to the tattoo group, mean 4.4 mm versus 5.7 mm (P < 0.01) and patient time in treatment room was also decreased for the no-tattoo group: mean 19.7 min versus 21.3 min (P = 0.03). CONCLUSION Based on our preliminary results for a cohort of women receiving RNI for breast cancer treatment at our institution, omitting radiation tattoos while utilizing daily surface imaging led to improved patient setup accuracy and decreased patient time on the treatment machine. Utilizing daily surface imaging obviates the requirement for skin-based tattoos in this patient population, improves efficiency of machine utilization, and provides the means for a tattoo-free set-up to become standard practice.