The presence of extensive lymphovascular invasion (LVI) is associated with higher risks of local-regional recurrence compared to usual LVI in curatively treated breast cancer patients.

PURPOSE/OBJECTIVES: Several datasets have demonstrated a correlation between lymph-vascular invasion (LVI) and local-regional recurrence (LRR). Whether the observation of "extensive LVI" is a further and incremental determinant of LRR risk is unknown. We describe clinical outcomes in women with invasive breast cancer stratified by: 1) absence of LVI (neg), 2) LVI focal or suspicious (FS-LVI), 3) usual (non-extensive) LVI (LVI) and 4) extensive LVI (E-LVI).

MATERIALS/METHODS: Between 12/2009 and 8/2021, 8837 patients with early-stage breast cancer were treated with curative intent and were evaluable. Clinical-pathological details were abstracted by retrospective review. The description of LVI was abstracted from pathology reports. Recurrence and survival outcomes were compared based on the extent of LVI. A matched propensity score analysis compared outcomes between patients with LVI vs. E-LVI.

RESULTS: Of the 8837 patients studied, 5584 were neg, 461 had FS-LVI, 2315 had LVI, and 477 had E-LVI. Patient with E-LVI had an adverse risk profile compared to the other groups. The 5- and 10-year local regional recurrence (LRR) cumulative incidence estimates in patients with E-LVI were 9.6% (95% CI: 7.1-13) and 13% (95% CI: 10-17), which were significantly higher than observed in the usual LVI group (6.8% [5.7-7.9] and 10% [8.8-12], respectively). A statistically significant difference in LRR was demonstrated on univariable (HR 1.4, 95% CI [1.03-1.89], p-value 0.029) and multivariable regression analysis (HR 1.62, 95% CI [1.15-2.27], p-value 0.005) when compared to non-extensive LVI. In an alternative approach, we performed a 2:1 propensity-matched analysis comparing LVI to E-LVI patients. The hazard ratio for LRR (HR 1.47 (CI 1.02-2.14, p=0.041) was suggestive of a higher risk with E-LVI.

CONCLUSIONS: Our work suggests that patients with E-LVI are at a higher risk for LRR than those with usual LVI. For patients who are borderline candidates for regional nodal irradiation or PMRT, the finding of E-LVI might be decisive in favor of intensified treatment.