Introduction: Recently, breast conserving surgery (BCS) followed by radiotherapy has been gaining popularity for most patients with early breast cancer; though, this technique has justified to be comparable with mastectomy in view of long-term survival in certain selected groups of women. This surgical option includes lumpectomy and sentinel node biopsy with or without radiotherapy and presents potential advantages over radical procedures as it is potentially less invasive, less debilitating and more aesthetically acceptable. Oncoplastic breast surgery (OBS) is a novel approach that developed greatly in the last decades that combines BCS with concomitant breast reconstruction. The aim of this technique is to get a safe and complete removal of the tumorous lesion while achieving the best possible aesthetic result. OBS consists of large lumpectomy and remodelling techniques such as breast- reshaping by therapeutic reduction mammoplasty or volume reduction by local glandular flaps or regional/distant flaps. Hence this study aimed at comparing the patients who had undergone non-oncoplastic and oncoplastic breast conserving surgery based on the tumour characteristics and its postoperative complications. Associated risk factors such as positive margins and local recurrence were also evaluated. Materials and Methodology: This was a retrospective, observational, cohort study conducted on a group of patients treated for breast cancer for almost 2 years at the surgery department. Patients included were 18 years of age or older, female and had been treated with lumpectomy, either oncoplastic or non-oncoplastic. Patients were divided into two groups depending on the type of treatment received. Oncoplastic surgery included therapeutic mammoplasty and adjacent tissue transfer following lumpectomy and comprised in some cases a bilateral procedure. Therapeutic mammoplasty was performed in the case of breast hypertrophy (macromastia and gigantomastia) and superior, medial, or inferior pedicle mammoplasty. Each patient was then followed by a surgical team comprised of an oncological and a plastic surgeon. In the case of a bilateral procedure, one or two residents were also present to perform surgery on both sides at the same time. The option of the most appropriate procedure for each patient was made by the oncologist and the plastic surgeon depending on breast and tumour size and based on patient’s general conditions. Patient’s data were collected from existing patients’ medical records, from the initial diagnosis to the last visit and included: demographics (age and body mass index [BMI]), tumour size, tumour margin status, patients requiring re-excision, patients at the verge of receiving post-operative radiotherapy, time interval between surgery and radiotherapy, complications and length of follow-up. Both immediate (infection, non-healing wounds, wound dehiscence, nipple necrosis, hematomas and seromas) and long-term (skin retraction and fat necrosis) complications were considered in the analysis. Complications were evaluated both by the plastic surgeon and an oncological surgeon. All data were analysed statistically. Primary analyses were conducted to compare patients based on breast conserving surgery type (i.e., non-oncoplastic vs. oncoplastic). Differences between the two groups were assessed by Chi- square test. A p-value of <0.05 was considered statistically significant. Statistical analysis was performed using SPPS software for Windows. Results: 225 patients were included as study participants in the study. Four patients underwent bilateral lumpectomy because of bilateral cancer. Non-oncoplastic surgery was performed on 160 (72.3%) patients while 61 (27.6%) underwent an oncoplastic procedure; after lumpectomy patients were treated with post-operative radiation whenever necessary. Data related to patients’ demographics, tumor details and follow-up are summarized in Table I. None of the patients presented with multicentric tumor and the median size of the lesion was not statistically different between the two groups: 1.4±0.9 vs. 1.3±0.7 (range 0.01-4;) for mammoplasty and oncoplastic surgery, respectively. The percentage of patients requiring re- excision was twice greater for women in the non-oncoplastic group: 12.9% vs. 6.5% in the oncoplastic group and the difference was statistically significant (p<0.05). However, the number of patients receiving post-operative radiation, the interval between surgery and radiotherapy and follow-up were similar between the two groups and the statistical analysis did not show any significant difference. Median follow-up was 43.3±21.1 months in the non- oncoplastic group and 44.8±16.0 months in the oncoplastic group. Only one patient (0.6%) experienced local recurrence after non-oncoplastic surgery, while no one recurred after the oncoplastic procedure. The rate of complications was slightly higher in the oncoplastic group, where three patients (4.9%) reported complications after surgery, while in the non- oncoplastic group complications were observed only in 2 patients (1.3%). The main complications reported by patients were hematoma (80%), non-heling wound (60%), and infection (20%) and wound dehiscence (20%). Patients received the following treatments in case of seroma formation: elasto-compressive medications, suction drain and possible guided external drainage of collected serum. There was no difference in the post-operative treatment received by patients in the two groups. No long-term complications were registered in our study. Conclusion: From this study it has been concluded that the oncoplastic surgery can be proposed for patients with tumours with unfavourable characteristics for traditional breast conservation surgery. Although it is used for the treatment of larger and multifocal tumours and surgical re-excisions were less often performed and was not related to higher rates of conversion to mastectomy or increased risk of local recurrence. Even though the overall complications were higher in the oncoplastic group, the incidences of major complications were similar in both groups. It should be considered as a safe tool to expand the indications of breast conservation surgeries.