Contemporary Multi-Institutional Cohort of 550 Cases of Phyllodes Tumors (2007-2017) Demonstrates a Need for More Individualized Margin Guidelines

Abstract

PURPOSE Phyllodes tumors (PTs) are rare breast neoplasms, which have little granular data on margins. Current guidelines recommend ≥ 1 cm margins; however, recent data suggest narrower margins are sufficient, and for benign PT, a negative margin may not be necessary. METHODS We performed an 11-institution contemporary (2007-2017) review of PT practices. Demographics, surgical, and histopathologic data were captured. Logistic regression was used to estimate the association of select covariates with local recurrence (LR). RESULTS Of 550 PT patients, the majority underwent excisional biopsy (55.3%, n = 302/546) or lumpectomy (wide excision) (38.5%, n = 210/546). Median tumor size was 30 mm, 68.9% (n = 379) were benign, 19.6% (n = 108) borderline, and 10.5% (n = 58) malignant. Surgical margins were positive in 42% (n = 231) and negative in 57.3% (n = 311). A second operation was performed in 38.0% (n = 209) of the total cohort, including 51 patients with an initial negative margin (82.4% with < 2 mm), and 157 with an initial positive margin, with residual disease only found in six (2.9%). Notably, 32.0% (n = 74) of those with an initial positive margin did not undergo a second operation, among whom only 2.7% (n = 2) recurred. Recurrence occurred in 3.3% (n = 18) of the total cohort (n = 15 LR, n = 3 distant), at median follow-up of 36.7 months. LR (all PT grades) was not reduced with wider negative margin width (≥ 2 mm v < 2 mm: odds ratio [OR] = 0.39; 95% CI, 0.07 to 2.10; P = .27) or final margin status (positive v negative: OR = 0.96; 95% CI, 0.26 to 3.52; P = .96). CONCLUSION In current practice, many patients are managed outside of current guidelines. For the entire cohort, a wider margin width was not associated with a reduced risk of LR. We do not recommend re-excision of a negative margin for benign PT, regardless of margin width, as a progressively wider surgical margin is unlikely to reduce LR.

Malignant phyllodes tumor and primary breast sarcoma; distinct rare tumors of the breast

“…For example, a SEER study of MP had an average age of 51.7; a U.S. multi‐institutional cohort study demonstrated a median age of 44 among MP patients; and a French multi‐institutional study of MP patients had a median age of 52.8. None of these studies reported any cases in men 20,23,27 . PBS is also female dominant and occurs typically in the 5th to 6th decades of life 26 .…”

AGO Recommendations for the Diagnosis and Treatment of Patients with Early Breast Cancer: Update 2021

“…Phyllodes tumors are classified as benign, borderline, and malignant, with varying risk of local recurrence. Recently, it has been shown that narrow margins for phyllodes tumors are not associated with an increased risk of local recurrence, and it was proposed that a negative margin may not be necessary for benign phyllodes tumors [71]. Therefore, the AGO has agreed to revise the minimal resection margins required for borderline and malignant phyllodes tumors, and a resection margin of 1 mm is now considered sufficient (LoE 2b/B/AGO++).…”

Immediate Deep Inferior Epigastric Perforator Flap Reconstruction of a Giant Phyllodes Tumor

“…The risk of recurrence is multifactorial and is associated with malignant grade, necrosis, the presence of stomal overgrowth, tumor size, and marked or moderate aplasia. There remains debate on the margin status and local recurrence, as some propose it is dependent on tumor grade [ 5 ]. However, current National Comprehensive Cancer Network (NCCN) guidelines recommend wide local excision with 1 cm margins to prevent a recurrence.…”