In the current study, 10.4% of the cases in the oncoplastic group needed surgery, while the rate for the conventional breast-conserving surgery was 18.4%, which could be because of more removal of breast tissue in breast-conserving and maintenance of the natural appearance of it in the oncoplastic surgeries. Similar results were also obtained in the similar studies. In a study conducted by Matrai et al. (
31) the data of 60 cases with oncoplastic and 60 cases with conventional breast-conserving surgeries were compared. The size of tumor, the prevalence of quadrantectomy, metastasis to the local lymph nodes, and adjuvant chemotherapy were significantly higher in the oncoplastic group compared to the other group. Longer surgery time, higher weight of the cases, and less positive margin cases were reported in the oncoplastic group compared to the other group. There was a significant statistical difference between the groups regarding the prevalence of complications and adjuvant therapy onset time interval. The surgery cosmetic outcomes were significantly better in the oncoplastic group compared to the other group. Also, the level of pain in hand, shoulders, and chest were lower in the oncoplastic group. Totally, the researchers reported that the oncoplastic surgery was preferred to the conventional breast-conserving surgery regarding the extraction of breast tumors, even big ones. Oncoplastic surgery with less complication does not cause any delay in the adjuvant therapies; therefore, this method does not increase the risk of recurrence. Likewise, the good cosmetic outcomes of this method should also be considered (
31).
Although breast oncoplastic surgeries let the surgeon perform a wider resection of tissue, the conducted tissue repair can make the evaluation of positive margin difficult. In the conducted studies, the rates of positive margin were reported as 2.7% to 22%, which were in association with the higher stages of cancer, positive lymph nodes, and positive lymphovascular invasion, using neoadjuvant chemotherapy, larger T, estrogen receptor, and lower age (
32). In many oncoplastic margin methods, dermoglandular flaps are used, which transfer breast tissue from one side to another. If the surgery should be followed-up in the second stage, due to the malignancy on the peripheries, it turns into a challenge and makes the decision making for the cuts difficult (
33). Frozen section is also used as a diagnosis method to evaluate tumor margin during the surgeries. Compared with those of paraffin method, the sensitivity and the accuracy of this method were 83% and 96%, respectively (
34).
In another study, 440 cases of conventional breast-conserving surgery and 150 cases of oncoplastic surgery (in 146 females) were compared and the results showed that the rate of second surgery in the oncoplastic group was lower than that of the conventional one (2.7% compared to 13.4%). Local relapse in the conventional and the oncoplastic groups were 2.7% and 1.3%, respectively. Authors concluded that the probability of the second surgery in the oncoplastic group was lower than that of the conventional group (
29).
In a study carried out by Down et al. (
35) the conventional breast-conserving and the oncoplastic surgeries were employed for 121 and 37 subjects, respectively. In their study, the size of tumor in the groups with conventional and oncoplastic surgeries were 23.9 and 17.6 mm respectively, which showed statistically significant difference (P = 0.002). Also, the mean weight and size of tumor in the subjects of oncoplastic and conventional surgery groups were 231.1 and 58.1 g, respectively. The rate of margin in the oncoplastic and conventional surgery groups were 14.3 and 6.1 mm, respectively, which showed statistically significant difference (P = 0.00001). The suitable margin for the oncoplastic group can reduce the rate of need for the second surgery to 5.4%, compared to 28.9% rate of surgery need in the conventional group. The oncoplastic breast-conserving surgery is more successful compared to the conventional surgery regarding the treatment of large breast tumors by creating safe and suitable margin, which reduces the risk of subsequent surgeries in the positive margin subjects.
The present study proposed surgical therapy to the cases with positive margin. The radiotherapy was performed as an alternative treatment to the cases, who did not agree to the surgery (9 out of 44 cases with positive margin). No relapse was reported in the radiotherapy group during the two-year follow-up.
In the current study, 89.6% and 81.6% of the cases in the oncoplastic surgery and conventional breast-conserving surgery groups had negative margin (P= 0.043), which was compatible with the result of the other studies. Kaur et al. (
30) evaluated 60 patients with breast cancer in 2 groups of oncoplastic surgery and conventional surgery. In the oncoplastic surgery and conventional surgery groups, 80.4% and 56.7% of the cases had negative margin, respectively (P = 0.05). The average distance between the surgical margin of the oncoplastic group and that of the conventional group were 8.5 and 6.5 mm, respectively, which had no statistically significant differences (P = 0.074). Researchers reported that the oncoplastic surgery was preferred to the conventional surgery since more size of tissue with higher margin can be removed by this method and it reduces the risk of positive margin (
30).
The main objective of this study was to compare surgical margin after breast cancer surgery between oncoplastic technique and conventional breast-conserving surgery. Positive margin in oncoplastic group was less than that of in conventional breast-conserving surgery group (10.4 % vs 18.4 %), meaning that the oncoplastic method, as a breast cancer surgery, can play an important role in reducing positive margin cases, compared to the conventional breast-conserving surgery.