INTRODUCTION Oncoplastic breast surgery (OPS), has widened the scope of breast conserving surgery (BCS) enabling larger resections with acceptable oncological safety and cosmetic outcomes. It often involves longer incisions and additional contralateral symmetrization procedures on the normal breast. However, patient’s perceptions on outcome may differ from that of the clinician and it is essential to evaluate feedback from patients undergoing OPS to determine the acceptability of these complex procedures in clinical practice. In this regard Health-related quality of life measures (HR-QoL) are an excellent means of evaluating the outcome of medical care. Further, it is well known that socio-cultural differences may reflect on the attitude of patients to treatment outcome and most of the data on OPS and HR-QoL available reflect western thought processes. Based on the feedback of our patients we designed a simple and practical patient-reported outcome measure (PROM) questionnaire reflecting the important issues as voiced by our patients and validated it using the QQ-10, indicating good face validity and acceptability of our questionnaire. We undertook this study to understand the acceptability of OPS level I and II procedures and to determine the satisfaction with the cosmetic outcome as well as the need for contralateral symmetrization procedures in our patients. PATIENTS AND METHODS Based on patient feedback, a questionnaire (Q-IN) was developed and validated by the QQ-10. It includes 9 questions reflecting three domains of general acceptability of the procedure, satisfaction with cosmetic outcome and degree of functional impairment in terms of altered sensation. 126 patients with breast cancer who underwent OPS level I or II without contralateral symmetrization were included in the study. Q-IN was self-administered during routine follow-up, following surgery, between January 2017 and December 2018. It was validated by 31 patients (24.6%)who also answered the QQ-10, a questionnaire designed to assess patients’ views on their experience of using PROM questionnaires during their medical care. The mean value score of the Q-IN as per the QQ-10 was high (84.79%, SD 11.7%) and mean burden score was low (20.96%, SD 24.6%) indicating that it has good face validity and is relevant and acceptable to our patients.RESULTS Mean age of patients was 51 years (21-77 years) and median follow up was 41 months (2- 156 months) following OPS. Majority of patients 124 (98%) were happy about undergoing BCS and had no doubts about the procedure. Most, 115 (91%) were very happy with the cosmetic appearance (shape, size and overall appearance) of the breast after OPS, 10 (8%) were happy and 1 patient (1%) was unhappy. Although most, 103 (81.7%) women, noticed a difference in size the majority 92 (89.3%) felt it was minimal and only 8 (7.8%) found a major difference in size. Of the 78 (61.9%) women that felt a difference in shape, 63 (80.8%) felt it was minimal and 11 (14.1%) reported a major difference. The quality of life of 23 (18.3%) patients was affected by the change in shape and size of the breast. Of these 17(74 %) only thought about the change in appearance, and in 6 (26%) it made a minor difference. Breast sensation was altered in 76 (63.3%) women and that of the nipple-areola complex (NAC) in 77 (58.7%). Of them, 25 (32.9%) reported no sensation in the breast and 30 (40.5%) felt no sensation in the NAC. When asked about a contralateral symmetrization procedure on the normal breast, only 2 (2%) said they would want to undergo symmetrization surgery. CONCLUSIONS Most patients undergoing level I or II oncoplastic breast surgery are happy and satisfied with the overall cosmetic and functional outcome. Only 2% of patients would like to undergo a contralateral symmetrization procedure to match the operated breast. Citation Format: Vinay Deshmane, Anuja Raniwala, Clotilda Cardoza. Patient-reported outcome after oncoplastic breast conservation surgery using level I or II techniques without contralateral symmetrization [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-11-35.