Abstract PO5-26-07: Surgery for Invasive Lobular Carcinoma: A Patient Experience Survey from the Lobular Breast Cancer Alliance

Abstract The Lobular Breast Cancer Alliance (LBCA) is a nonprofit, patient advocacy organization committed to raising awareness and promoting research into invasive lobular carcinoma (ILC). While ILC accounts for 15% of breast cancers, knowledge about ILC remains limited. ILC’s hallmark is lack of E-cadherin, which results in non-cohesive formation and impacts accuracy of imaging tests and staging. Consequently, patients with ILC have higher rates of positive surgical margins, mastectomies, and axillary lymph node (LN) dissections. To understand the surgery experience of individuals with ILC, LBCA conducted an anonymous online survey from 6/21-7/2/23, distributed via the LBCA newsletter, social media, and partner organizations. Questions addressed pre-operative imaging, type of surgery, surgical margins, LN status, decision making about and patient experience with surgery. Analyses were limited to those respondents who had surgery. Study limitations include potential recall and selection bias. Results 1,482 individuals with a diagnosis of ILC completed the survey and 1,426 had undergone surgery. 76% were from North America, 11% from England, and 4% from Australia. Average age at diagnosis was 56 (range 31-86). At diagnosis, 38% were clinically stage 1; 37% stage 2; 17% stage 3; and 4% de novo metastatic. 75% had a mammogram that indicated dense breasts. Of 1,426 surgery respondents (SR), 95% reported that ILC was identified in only one breast at diagnosis. 80% had a pre-surgical MRI. MRI revealed larger tumors than seen on other imaging for 43% and revealed previously unseen contralateral ILC for 3%. 375 (26%) of SRs were diagnosed with ipsilateral disease and had a pre-surgical MRI that did not reveal new information about their ILC. Of these, post-surgical pathology reports indicated 16% had additional ipsilateral foci, 2% contralateral disease, and 40% had larger tumors than seen on pre-surgical imaging. 614 (43%) of SRs had one or more lumpectomy (L), 560 (39%) of SRs had a double mastectomy (DM), and 451 (32%) of SRs had a single mastectomy (SM). 123 (20%) of SRs who had one or more Ls, had a subsequent SM or DM. For those undergoing L (614), reasons for this choice included: recommendation from their care team (83%), wanted to keep their breast (25%), thought it was better for their overall survival (OS) (14%), and 13% indicated they wanted breasts but did not want reconstruction. Of the 560 women who had a DM, 60% indicated that they thought a DM would improve their OS, 50% were concerned about the risk of local recurrence, 47% doubted that imaging would detect future ILC tumors, and 45% noted concern that ILC is more likely to be bilateral. Of note, only 9% had ILC or ILC and another invasive breast cancer in both breasts at initial diagnosis and 31% who had a pre-surgical MRI changed their initial surgical treatment plan. Post surgery, pathology for DM group revealed larger tumors than seen on imaging (57%), and 6% had tumors found in a second breast that were not seen on imaging. For those 451 who had an SM, reasons for this choice included: 75% said it was what their care team recommended, 35% thought it would improve OS, 20% feared risk for local recurrence, and 15% doubted imaging would detect future ILC. Of 614 respondents who had L, 33% had positive margins at first surgery. Of those, 17% reported multiple Ls and M; and 24% reported clear margins were never achieved. Of the 1011 SM or DMs reported, 10% did not achieve clear margins after these surgeries. Conclusion The survey demonstrates the experience of a large cohort of women with ILC, reporting high rates of uncertainty about accuracy of imaging, high rates of repeat surgery, bilateral mastectomies, and positive margins. Patients are factoring concerns about potential extent of disease and future recurrence in their surgical decision making. These results support the need for improved pre-operative staging and imaging modalities specific to ILC. Citation Format: Laurie Hutcheson, Janice Axelrod, Tracy Cushing, Colleen Fitzwater, Rinath Jeselsohn, Gitte Joergensen, Maria Karsten, Miranda Kimm, Megan Kruse, Theresa Langdon, Julia Levine, Mason Mitchell-Daniels, Rita Mukhtar, Barbara Neilsen, Shani Paluch-Shimon, Therese Pross. Surgery for Invasive Lobular Carcinoma: A Patient Experience Survey from the Lobular Breast Cancer Alliance abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-26-07.