Predicting outcomes for locally advanced rectal cancer treated with neoadjuvant chemoradiation with CT-based radiomics.

A feasibility study was performed to determine if CT-based radiomics could play an augmentative role in predicting neoadjuvant rectal score (NAR), locoregional failure free survival (LRFFS), distant metastasis free survival (DMFS), disease free survival (DFS) and overall survival (OS) in locally advanced rectal cancer (LARC). The NAR score, which takes into account the pathological tumour and nodal stage as well as clinical tumour stage, is a validated surrogate endpoint used for early determination of treatment response whereby a low NAR score (< 8) has been correlated with better outcomes and high NAR score (> 16) has been correlated with poorer outcomes. CT images of 191 patients with LARC were used in this study. Primary tumour (GTV) and mesorectum (CTV) were contoured separately and radiomics features were extracted from both segments. Two NAR models (NAR > 16 and NAR < 8) models were constructed using Least Absolute Shrinkage and Selection Operator (LASSO) and the survival models were constructed using regularized Cox regressions. Area under curve (AUC) and time-dependent AUC were used to quantify the performance of the LASSO and Cox regression respectively, using ten folds cross validations. The NAR > 16 and NAR < 8 models have an average AUCs of 0.68 ± 0.13 and 0.59 ± 0.14 respectively. There are statistically significant differences between the clinical and combined model for LRFFS (from 0.68 ± 0.04 to 0.72 ± 0.04), DMFS (from 0.68 ± 0.05 to 0.70 ± 0.05) and OS (from 0.64 ± 0.06 to 0.66 ± 0.06). CTV radiomics features were also found to be more important than GTV features in the NAR prediction model. The most important clinical features are age and CEA for NAR > 16 and NAR < 8 models respectively, while the most significant clinical features are age, surgical margin and NAR score across all the four survival models.

A Prospective Randomized Controlled Trial to Compare the Use of Conventional Dark-Ink Tattoo and Ultraviolet-Ink Tattoo for Patients Undergoing Breast Radiation Therapy.

PURPOSE: Permanent tattoo marks used in radiation therapy remain for the duration of treatment and essentially for the rest of the patient's life. This study compared the initial positioning setup errors and body image perception between patients with ultraviolet (UV) and conventional dark ink tattoos. METHODS AND MATERIALS: Thirty-four patients from February 2018 to March 2019, who underwent radiation therapy (RT) to the breast or chest wall for ductal carcinoma in situ or breast cancer were prospectively recruited and randomized (1:1) to receive either conventional dark ink or UV ink tattoos. Each patient received the assigned tattoos during computed tomography (CT) simulation and initial treatment setup shifts were compared. A 9-item body-image survey was administered to all patients at 3 time points: CT simulation, last week of RT, and 6 weeks post-RT. Feedback from CT and treatment staff in terms of setup time and challenges were collated. RESULTS: The median age of the patient cohort was 46 years old. No statistically significant difference was observed between the mean setup errors for the conventional dark ink group (0.11 cm inferior, 0.01 cm left, 0.11 cm posterior) and UV ink group (0.01 cm superior, 0.01 cm right, 0.06 cm posterior; P = NS). Similar responses were observed in the body-image survey between the 2 groups across all time points (P = NS). The majority of the patients (dark ink 82.3% vs UV ink 88.2%) did not feel less sexually attractive as a result of the tattoo at 6 weeks post-RT. At 6 weeks post-RT, patients in both groups were satisfied with the appearance of the tattoo and did not feel cautious about their choice of clothes (82.4% vs 88.2%; P = NS). In addition, 88.6% of staff (n = 35) felt minimum effect of UV ink on the overall setup time, and 94.3% found no difficulty localizing the UV ink tattoos during patient positioning. CONCLUSIONS: No difference in setup accuracy was found using UV ink tattoos, and it could be implemented clinically with minimal effect on the existing workflow. Patients expressed high satisfaction and self-confidence with the use of UV ink tattoos.