Abstract P5-04-10: Consensus guidelines for breast cancer staging during pregnancy. A Delphi Study

Abstract Background: Breast cancer is the second most common cancer occurring during pregnancy with limited evidence for appropriate staging (1,2). A Delphi study was performed to develop consensus guidelines. Methods: Guideline recommendations were constructed based on available evidence and included statements targeting highlighted areas of uncertainty from a clinician-based survey. Statements were divided into two domains: one focused on indications for staging and the second addressed imaging selection. A two round Delphi study was performed. Medical, radiation and surgical oncologists from Australia and New Zealand were invited to participate. Participants who had worked in their field for >5 years were considered experts. Participants voted using a 9-point Likert scale selecting from 1 (strongly disagree) to 9 (strongly agree). Consensus was achieved when >75% participants selected < 3, or >7 for a statement. Statements that did not reach consensus in the first round were refined and re-presented for subsequent voting. Results: 15 Australian and New Zealand experts agreed to participate: 8 medical oncologists, 3 radiation oncologists and 4 breast surgeons. 87% (13/15) of participants completed round one. Of the 18 recommendations, six did not meet consensus. These were revised, with seven recommendations re-presented in round two. 11/13 (85%) participants completed round two, with one further recommendation achieving consensus. Consensus was achieved on indications for staging including women with locally advanced or inflammatory breast cancer and clinical suspicion of metastatic disease. Staging should be delayed until after pregnancy if it will not immediately change management decisions. Staging should not routinely be used in stage I and II breast cancers. Where staging is indicated, it was agreed that visceral disease should be screened for; however, consensus was not achieved for whether screening for bone metastases should be performed. There was consensus for liver ultrasound as the imaging modality of choice for liver metastases screening. Participants did not agree on whether chest x-ray or CT chest was best practice for pulmonary metastases nor optimal imaging for bone metastases. There was also discord as to whether there is a role for PET scan. Conclusion: Consensus guidelines have been developed to standardise breast cancer staging during pregnancy. Consensus was achieved for indications for staging and use of liver ultrasound to screen for liver metastases. Optimal staging practices for bone and pulmonary metastases warrants further investigation. Acknowledgements: We thank the experts who participated in this Delphi study. References: 1. Lee YY, Roberts CL, Dobbins T, Stavrou E, Black K, Morris J, et al. Incidence and outcomes of pregnancy-associated cancer in Australia, 1994–2008: a population-based linkage study. BJOG Int J Obstet Gynaecol. 2012;119(13):1572–82. 2. Cottreau CM, Dashevsky I, Andrade SE, Li DK, Nekhlyudov L, Raebel MA, et al. Pregnancy-Associated Cancer: A U.S. Population-Based Study. J Womens Health. 2019 Feb 1;28(2):250–7. Citation Format: Harriet R. Herbison, Abigail Miller, Darryl Shnier, Sally Greenberg, Bianca Devitt. Consensus guidelines for breast cancer staging during pregnancy. A Delphi Study. [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-04-10.