Abstract Background Chemotherapy-induced alopecia (CIA) is able to affect a patient's self-image and confidence negatively. A decade ago scalp cooling failed to avoid chemotherapy- induced hairloss in women who underwent chemotherapy as only thermal packs were used. The DigniCap® scalp cooling system consists of a silicon cap that includes two sensor controlled cooling cycles. These cycles regulate the scalp temperature to lead to a continuous vasoconstriction in the scalp. Thus, it is indicated to reduce the likelihood of CIA. Reduced temperature results in a reduced blood flow to the scalp area so that less chemotherapy reaches the hair cells. Therefore, these are not exposed to the full dose of chemotherapy and may be able to survive the treatment. The purpose of this study was to evaluate the effectiveness and adverse events of DigniCap® scalp cooling system. Patients and Methods Since October 2015, 48 of 60 planned breast cancer patients undergoing chemotherapy were prospectively included in a unicentric cohort study in the certified breast cancer center at AGAPLESION Markus Hospital, Frankfurt, Germany. The average age of the women was 52.7 years (range 33 – 76). The chemotherapy regimen included 4x EC q3w -> 12x paclitaxel q1w (60.4%), 4x TC q3w (8.3%), 6x carboplatin plus paclitaxel q3w (8.3%), 6x docetaxel, carboplatin, trastuzumab (TCbH) q3w + pertuzumab (4.1%), 4x nab-paclitaxel m 3 q4 (2.1%), 4x paclitaxel q2w -> 4x EC q2w (2.1%), 18x paclitaxel q1w (2.1%), 18x paclitaxel q1w plus myocet q1w (2.1%), eribulin d1, 8 q3 (2.1%), 4x EC q3w -> 12x paclitaxel q1w plus trastuzumab plus pertuzumab (2.1%), 6x carboplatin plus paclitaxel q3w plus bevacizumab (2.1%), 4x nab-paclitaxel3 q4 plus bevacizumab (2.1%), 4x nab-paclitaxel 3 q4 -> 4x EC q3w (2.1%). Our aim was to quantify the grade of alopecia, satisfaction and side effects of the scalp cooling system. Alopecia quantification was done by a standardized questionnaire and photo documentation. Final results of the whole cohort of 60 patients will be presented at SABCS 2017. Results The interim analysis showed a success rate of complete hair loss avoidance of 8.0%. Hair loss of less than 20% was documented in 60.0% (29 patients). In 19/ 48 patients (39.6%) adverse reactions caused by the DigniCap® Scalp Cooling System, like headache (12.5%) or CIA (27.1%) were reported. Conclusion Our evaluation shows that DigniCap® Scalp Cooling Systemhas a minimal rate of adverse events (39.6%) and reduces the likelihood of chemotherapy-induced alopecia (< 20% hair loss)effectively by 60.0%, even in anthracycline-based regimen. Citation Format: Traub L, Brandi C, Khandan F, Thill M. Effectiveness and adverse events of DigniCap® scalp cooling system [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-11-07.