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Author information

Yu JI1, Choi DH2, Huh SJ1, Cho EY3, Kim K4, Chie EK4, Ha SW4, Park IA5, Ahn SJ6, Lee JS7, Shin KH8, Kwon Y8, Kim YB9, Suh CO9, Koo JS10, Kim JH11, Jeong BG12, Kim IA13, Lee JH14, Park W1.

1Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.

2Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. Electronic address: doho.choi@samsung.com.

3Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.

4Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.

5Department of Pathology, Seoul National University College of Medicine, Seoul, Korea.

6Department of Radiation Oncology, Chonnam National University Medical School, Gwangju, Korea.

7Department of Pathology, Chonnam National University Medical School, Gwangju, Korea.

8Center of Breast Cancer, National Cancer Center, Goyang, Korea.

9Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Korea.

10Department of Pathology, Yonsei University College of Medicine, Seoul, Korea.

11Department of Radiation Oncology, Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Korea.

12Department of Radiation Oncology, Gyeongsang Institute of Health Sciences, Jinju, Korea.

13Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Korea.

14Department of Radiation Oncology, St. Vincent's Hospital, The Catholic University of Korea College of Medicine, Suwon, Korea.

Abstract

PURPOSE:

We designed the present study to investigate differences in prognostic factors and failure patterns between patients with invasive micropapillary carcinoma or carcinoma with micropapillary component (IMPC) and randomly matched patients with invasive ductal carcinoma (IDC) of the breast at multiple institutions of the Korean Radiation Oncology Group (KROG).

MATERIALS AND METHODS:

This retrospective multicenter study was performed using subjects treated from January 1999 to November 2011. Female patients who had undergone curative resection for breast cancer without neoadjuvant chemotherapy were considered for this study. Exact matches were made for age (± 3 years), pathologic tumor and node stage, treatment method (surgery with or without radiotherapy), and period when surgery was performed (within 1 year) at the same institution.

RESULTS:

A total of 534 patients were analyzed. The median follow-up period was 59 months in both groups. In the comparison of clinicopathologic characteristics, rates of lymphovascular invasion (LVI) and nuclear grade III were both significantly higher in IMPC than in IDC (P < .001, P = .01, respectively). During the follow-up period, recurrences developed in 40 patients with IMPC (15.0%) and 21 with IDC (7.9%). Locoregional recurrence (LRR) developed in 22 patients with IMPC (8.2%) and 10 with IDC (3.7%). The rate of distant metastasis did not differ between the 2 groups (P = .52). LRR-free survival (P = .03) and recurrence-free survival (P = .007) were significantly different between the 2 groups, but overall survival was not (P = .67).

CONCLUSION:

IMPC is associated with a higher rate of LVI, high nuclear grade, and a propensity for LRR compared to IDC. Modification of the locoregional treatment modality might be needed in this pathologic subtype of breast cancer.