The percentage of unnecessary mastectomy due to false size prediction using preoperative ultrasonography and MRI in breast cancer patients - a prospective cohort study

Q: What was the study’s main objective regarding mastectomy decisions?

To prospectively determine the proportion of total mastectomy decisions that resulted from false size prediction using imaging, particularly when considering potential breast-conserving surgery after neoadjuvant and non-neoadjuvant chemotherapy.

Q: How did the researchers compare imaging-based tumour size with reality?

Before surgery, surgeons recorded a hypothetical maximum tumour size that would have allowed breast-conserving surgery. After surgery, the hypothetical maximum was compared with the final pathological tumour extent, including both invasive and in situ cancers.

Q: Which imaging method contributed most to false predictions?

Magnetic resonance imaging contributed the most to false size predictions, and reducing false decisions without MRI was estimated to be possible.

Sep 24, 2026

Uploaded by Anna Hans

Prospective enrollment of stage II–III breast cancer patients undergoing planned total mastectomy between 2018 and 2021 evaluated how often imaging-based estimates overestimated tumour extent after neoadjuvant chemotherapy. Surgeons recorded a hypothetical maximum tumour size that would have supported breast-conserving surgery if the actual tumour was smaller. Postoperative pathology compared invasive and in-situ extent with that pre-recorded size, quantifying false decisions and assessing factors including HER2 and receptor status, and MRI versus ultrasonography discrepancies.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages7

Reading Time18 min

AccessFree to download

Prospective cohort study overview

Background

Materials and methods

Results

Conclusion

Keywords

’Prospective Cohort Study The percentage of unnecessary mastectomy due to false size prediction using preoperative ultrasonography and MRI in breast cancer patients who underwent neoadjuvant chemotherapy: a prospective cohort study Yireh Han, MDa , Ji Gwang Jung, MDb , Jang-il Kim, MDb , Changjin Lim, MDb,c,d , Hong-Kyu Kim, MD, PhDb,c,d , Han-Byoel Lee, MD, PhDb,c,d , Hyeong-Gon Moon, MD, PhDb,c,d , Wonshik Han, MD, PhDb,c,d,* Background: Imaging-estimated tumour extent after neoadjuvant chemotherapy tends to be discordant with the pathological extent. The authors aimed to prospectively determine the proportion of decisions regarding total mastectomy for potential breastconserving surgery candidates owing to false size prediction with imaging in neoadjuvant chemotherapy and non-neoadjuvant chemotherapy patients. Materials and methods: The authors prospectively enroled clinical stage II or III breast cancer patients who are scheduled for total mastectomy between 2018 and 2021 . This study was conducted at Seoul National University Hospital at South Korea. Before surgery, each surgeon recorded the hypothetical maximum tumour size at which the surgeon would have been able to attempt breast-conserving surgery if the patient had actually less than the size of the tumour at that location in the breast. After surgery, the hypothetical maximum tumour size was compared with the ﬁnal pathologic total extent of the tumour, including invasive and in situ cancers. Results: Among the 360 enroled patients, 130 underwent neoadjuvant chemotherapy, and 230 did not undergo neoadjuvant chemotherapy. Of the total of each group, 47 .7% in the neoadjuvant chemotherapy group and 21 .3% in the non-neoadjuvant chemotherapy group had a smaller pathologic tumour extent than the pre-recorded hypothetical maximum tumour size (P < 0.001) . Further analyses were conducted for the neoadjuvant chemotherapy group. The proportions of total mastectomy with false size prediction were higher in HER2-positive (63.3%) and triple-negative (57.6%) patients compared with ER-positive/HER2-negative (25 .0%) patients (P < 0.001) . Both magnetic resonance imaging-pathology and ultrasonography-pathology size discrepancies were signiﬁcantly associated with false decisions for total mastectomy (both P < 0.001) . Without magnetic resonance imaging, the false decision may be reduced by 21 .5% . Conclusion: A total of 47 .7% of patients who received total mastectomy after neoadjuvant chemotherapy were breast-conserving surgery eligible, which was signiﬁcantly higher than that of non-neoadjuvant chemotherapy patients. Magnetic resonance imaging contributed the most to false size predictions. Keywords: breast cancer, hypothetical maximum tumour size, neoadjuvant chemotherapy Introduction Breast-conserving surgery (BCS) has been a standard surgical procedure for early breast cancer patients since pivotal randomized clinical trials, such as the National Surgical Adjuvant Breast and Bowel Project B-06 and a study conducted at the Milan Cancer Institute[1,2] . However, a signiﬁcant proportion of aDepartment of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, bDepartment of Surgery, Seoul National University College of Medicine, cBiomedical Research Institute, Seoul National University Hospital and dCancer Research Institute, Seoul National University, Seoul, Republic of Korea Poster presentation atASCO 2022 was undergone. Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article. *Corresponding author. Address: Department of Surgery, Seoul National University Hospital, Seoul, Republic of Korea, Cancer Research Institute, Seoul National University, Seoul, Republic of Korea, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea. Tel.: +822 207 219 58. fax: +822 [766 3975. E-mail: hanw@snu.ac.kr](766 3975. E-mail: hanw@snu.ac.kr) (W. Han). Copyright © 2023 The A

FAQs

What was the study’s main objective regarding mastectomy decisions?

To prospectively determine the proportion of total mastectomy decisions that resulted from false size prediction using imaging, particularly when considering potential breast-conserving surgery after neoadjuvant and non-neoadjuvant chemotherapy.

How did the researchers compare imaging-based tumour size with reality?

Before surgery, surgeons recorded a hypothetical maximum tumour size that would have allowed breast-conserving surgery. After surgery, the hypothetical maximum was compared with the final pathological tumour extent, including both invasive and in situ cancers.

Which imaging method contributed most to false predictions?

Magnetic resonance imaging contributed the most to false size predictions, and reducing false decisions without MRI was estimated to be possible.

Sep 24, 2026

Uploaded by Anna Hans