Oncologic Safety of Immediate Oncoplastic Surgery Compared to Standard Breast Conserving Surgery for Patients with Invasive Lobular Carcinoma

Israel Falade1, Kayla Switalla2,3, Astrid Quirarte3, Molly Baxter3, Daniel Soroudi1, Harriet Rothschild1, Shoko Emily Abe3, Karen Goodwin3, Merisa Piper4, Jasmine Wong3, Robert Foster4, Rita A Mukhtar3

Abstract:
Background: Invasive lobular carcinoma (ILC) of the breast grows in a diffuse pattern, resulting in high risk of positive margins at surgical resection. Oncoplastic approaches have been shown to reduce this risk, but there are persistent concerns around the safety of immediate oncoplastic surgery for those with ILC.

Hypothesis: Immediate oncoplastic surgery would be associated with reduced rate of positive margins, higher rates of successful breast conservation and no increased risk of cancer recurrence.

Aims: This study aimed to evaluate the short and long-term oncologic outcomes for immediate oncoplastic surgery in patients with ILC.

Methods: We retrospectively analyzed an institutional database of stage I-III ILC patients who underwent breast-conserving surgery (BCS) with or without immediate oncoplastic surgery (oncoplastic closure or oncoplastic reduction mammoplasty [ORM]). We compared positive margin rates, rates of successful BCS, and recurrence-free survival (RFS) by type of surgery.

Results: In 494 patients, we found that the use of immediate ORM was associated with significantly lower odds of positive margins (odds ratio [OR] 0.34, 95% CI 0.17-0.66, p=0.002). Both lumpectomy with oncoplastic closure and ORM were significantly associated with higher rates of successful BCS compared to standard lumpectomy (94.2%, 87.8%, and 73.9% respectively, p<0.001). There was no difference in RFS in those undergoing immediate oncoplastic surgery compared to standard lumpectomy alone.

Conclusions: Patients with stage I-III ILC who underwent immediate oncoplastic surgery had significant benefits including lower odds of positive margins, higher rates of successful BCS, and both types of immediate oncoplastic surgery showed similar RFS compared to lumpectomy alone. This supports the oncologic safety of immediate oncoplastic surgery in diffusely growing tumors like ILC, making it an ideal option for patients desiring BCS.