Background: Locoregional recurrence after mastectomy for breast cancer may predict distant recurrence andmortality. This study examined the pattern and rates of post-mastectomy locoregional recurrence (PMLRR),survival outcome and prognostic factors for isolated PMLRR (ILR) in a breast cancer cohort in University ofMalaya Medical Center (UMMC).
Methods: We studied 522 patients who underwent mastectomy between 1998and 2002 and followed them up until 2008. We defined PMLRR as recurrence to the axilla, supraclavicular nodesand or chest wall. ILR was defined as PMLRR occurring as an isolated event. Prognostic factors for locoregionalrecurrence were determined using the Cox proportional hazards regression model.
Results: The overall PMLRRrate was 16.4%. ILR developed in 42 of 522 patients (8.0%). Within this subgroup, 25 (59.5%) remained diseasefree after treatment while 17 (40.5%) suffered disease progression. Univariate analyses identified race, age,size, stage, margin involvement, lymph node involvement, grade, lymphovascular invasion and ER status asprobable prognostic factors for ILR. Cox regression resulted in only Stage III disease and margin involvementas independent prognostic factors. The hazard of ILR was 2.5 times higher when the margins were involvedcompared to when they were clear (aHRR 2.5; 95% CI 1.3 to 5.0). Similarly, compared with stage I those withStage II (aHRR 2.1; 95%CI 0.6 to 6.8) and stage III (aHRR 4.6; 95%CI 1.4 to 15.9) had worse prognosis for ILR.
Conclusion: Margin involvement and Stage III disease were identified to be independent prognostic factors forILR. Close follow-up of high risk patients and prompt treatment of locoregional recurrence were recommended.