11610 Background: Hair loss is a frequently occurring and stigmatizing side effect of chemotherapy. Worldwide scalp cooling is being introduced to prevent chemotherapy-induced alopecia (CIA). In the Netherlands scalp cooling is implemented in many hospitals since 2005. FDA clearance has been approved for scalp cooling among breast cancer patients in the USA in 2016. Recently approval has been expended for solid tumors. Methods: In a prospective, longitudinal registry data have been collected between 2006 and 2017. Patients could be included if they received chemotherapy that induced severe alopecia, regardless type of solid tumor, stage of disease, age, gender or receiving adjuvant or palliative treatment. Patients were eligible for evaluation of hair loss after they received at least 2 cycles of chemotherapy or if they ceased scalp cooling because of severe hair loss after the first cycle. Failure was defined as feeling the need to use a wig or head cover. Data will be presented using descriptive statistics and multivariate regression analysis to explore determinants of scalp cooling efficacy per largest groups of chemotherapy regimen, and evaluate variety between hospitals. Results: Preliminary results show data of 7378 patients from 68 hospital locations of whom 75% had breast cancer and 8% prostate cancer. Overall 57% of patients did not feel the need to wear a wig or head cover. Variation was observed between hospitals in scalp cooling procedures: e.g. wetting the hair (0-100% of patient) and cooling- and infusion times that varied per type of chemotherapy. Also results varied between hospitals per type and dose of chemotherapy (n > 10 patients), e.g. minimal 37% and maximal 86% success rates between hospitals for paclitaxel-carboplatin (n = 498), 17-54% success for irinotecan monotherapy (n = 275), 25-79% success for 5FU/epirubicin/cyclophosphamide-docetaxel (n = 843) and 79-94% for docetaxel monotherapy (n = 824). Also variation in satisfaction with information about scalp cooling and nursing expertise was observed. Results from the regression analyses will be presented at the conference. Conclusions: Scalp cooling efficacy varied enormously between hospitals. A registry is a useful tool to identify best practices and to provide guidance to further improve results. An international registry has been set up to also collect data on CIA among scalp cooled and non-scalp cooled patients in the USA, Australia and the UK.