Prognostic factors in breast phyllodes tumors: a nomogram based on a retrospective cohort study of 404 patients

Abstract

The aim of this study was to explore the independent prognostic factors related to postoperative recurrence-free survival (RFS) in patients with breast phyllodes tumors (PTBs). A retrospective analysis was conducted in Fudan University Shanghai Cancer Center. According to histological type, patients with benign PTBs were classified as a low-risk group, while borderline and malignant PTBs were classified as a high-risk group. The Cox regression model was adopted to identify factors affecting postoperative RFS in the two groups, and a nomogram was generated to predict recurrence-free survival at 1, 3, and 5 years. Among the 404 patients, 168 (41.6%) patients had benign PTB, 184 (45.5%) had borderline PTB, and 52 (12.9%) had malignant PTB. Fifty-five patients experienced postoperative local recurrence, including six benign cases, 26 borderline cases, and 22 malignant cases; the three histological types of PTB had local recurrence rates of 3.6%, 14.1%, and 42.3%, respectively. Stromal cell atypia was an independent prognostic factor for RFS in the low-risk group, while the surgical approach and tumor border were independent prognostic factors for RFS in the high-risk group, and patients receiving simple excision with an infiltrative tumor border had a higher recurrence rate. A nomogram developed based on clinicopathologic features and surgical approaches could predict recurrence-free survival at 1, 3, and 5 years. For high-risk patients, this predictive nomogram based on tumor border, tumor residue, mitotic activity, degree of stromal cell hyperplasia, and atypia can be applied for patient counseling and clinical management. The efficacy of adjuvant radiotherapy remains uncertain.

Keywords: Adjuvant radiotherapy; clinicopathologic features; local recurrence; phyllodes tumor of the breast; surgical treatment.

Figure 1

Log‐rank test for low‐risk PTB. (A) Premenopausal versus Postmenopausal (log‐rank P = 0.012); (B) With a history of fibroadenoma surgery versus without a history of fibroadenoma surgery (log‐rank P = 0.006); (C) Interstitial (stromal) cell atypia (low vs. moderate, log‐rank P = 0.188).

Figure 2

Log‐rank test for high‐risk PTB. (A) With fibroadenoma surgery history versus without a history of fibroadenoma surgery (log‐rank P < 0.0001); (B) Surgery methods (SE vs. WLE vs. M, log‐rank P = 0.087); (C) With tumor residual versus without tumor residual (log‐rank P = 0.009); (D) Mitosis per 10 HPF (0–3 vs. 4–9 vs. more than 10, log‐rank P < 0.0001). M, mastectomy.

Figure 3

Log‐rank test for high‐risk PTB. (A) Interstitial (stromal) cell hyperplasia (low vs. moderate vs. high, log‐rank P < 0.0001); (B) Interstitial (stromal) cell atypia (low vs. moderate vs. high, log‐rank P = 0.018); (C) Tumor border (clear vs. invasion, log‐rank P < 0.0001).

Figure 4

Nomogram for predicting recurrence‐free survival (RFS) of patients with phyllodes tumors. To use the nomogram, locate the first variable. Draw a line straight upwards to the Points axis to determine the number of points received for the variable. Repeat this process for the other variables, and sum up the points achieved for each variable. The sum of these numbers is located on the Total Points axis, and a line is drawn downwards to the survival axes to determine the likelihood of 1‐, 3‐, and 5‐year RFS.

Figure 5

Bootstrapped estimates of calibration accuracy at (A) 1‐year RFS, (B) 3‐year RFS, and (C) 5‐year RFS. The ideal outcome (dot line) and the observed outcome (maroon line) are depicted. This figure demonstrates how accurately predictions at different risk levels conform to observed outcomes for the nomogram.