Patterns and Risk Factors of Locoregional Recurrence in T1-T2 Node Negative Breast Cancer Patients Treated With Mastectomy: Implications for Postmastectomy Radiotherapy

Abstract

Purpose Postmastectomy radiation therapy (PMRT) can reduce locoregional recurrences (LRR) in high-risk patients, but its role in the treatment of lymph node negative (LN−) breast cancer remains unclear. The aim of this study was to identify a subgroup of T1-T2 breast cancer patients with LN− who might benefit from PMRT. Methods and Materials We retrospectively reviewed 1,136 node-negative T1-T2 breast cancer cases treated with mastectomy without PMRT at the Massachusetts General Hospital between 1980 and 2004. We estimated cumulative incidence rates for LRR overall and in specific subgroups, and used Cox proportional hazards models to identify potential risk factors. Results Median follow-up was 9 years. The 10-year cumulative incidence of LRR was 5.2% (95% CI: 3.9–6.7%). Chest wall was the most common (73%) site of LRR. Tumor size, margin, patient age, systemic therapy, and lymphovascular invasion (LVI) were significantly associated with LRR on multivariate analysis. These five variables were subsequently used as risk factors for stratified analysis. The 10-year cumulative incidence of LRR for patients with no risk factors was 2.0% (95% CI: 0.5–5.2%), whereas the incidence for patients with three or more risk factors was 19.7% (95% CI: 12.2–28.6%). Conclusion It has been suggested that patients with T1-T2N0 breast cancer who undergo mastectomy represent a favorable group for which PMRT renders little benefit. However, this study suggests that select patients with multiple risk factors including LVI, tumor size ≥2 cm, close or positive margin, age ≤50, and no systemic therapy are at higher risk of LRR and may benefit from PMRT.

Postmastectomy radiotherapy: Indications and implications

“…17 Abi-Raad et al 18 also looked at node-negative patients and recommended that radiotherapy be considered in patients with 3 or more recurrence risk factors, defined as close or positive margins, age 50, tumour size 2 cm, no systemic therapy and lymphovascular invasion. The 10-year locoregional recurrence incidence was 19.7% in patients with three or more of these risk factors, in comparison with only 2% in those patients with none of these risk factors.…”

Strahlentherapie

“…Für Patientinnen mit pN0 und intermediärem Risiko ist die Indikation zur RT der Thoraxwand nach Mastektomie nicht ausreichend abgesichert [1,16]. Nur eine Minderheit der Abstimmungsberechtigten sah beim Zusammentreffen vieler Risikofaktoren [1,4,16,17,22] eine relative Indikation zur RT der Thoraxwand.…”

“…Nur eine Minderheit der Abstimmungsberechtigten sah beim Zusammentreffen vieler Risikofaktoren [1,4,16,17,22] eine relative Indikation zur RT der Thoraxwand.…”

Are there patients with T1 to T2, lymph node‐negative breast cancer who are “high‐risk” for locoregional disease recurrence?

“…1 Indications for PMRT in T1-T2N0 patients thought to be at increased risk for LRR are controversial, due to a lack of consensus on what constitutes “high-risk” in the absence of nodal metastasis. 1-7 The most consistently described characteristics associated with LRR in retrospective studies include age less than 40 years, the presence of lymphovascular invasion (LVI), tumor size, and high nuclear grade, with reported rates of LRR as high as 20% in women with multiple risk factors. 1, 4 Multifocal or multicentric cancer has also been associated with increased risk of LRR.…”