Association of HER-2 Status and Systemic Immune-Inflammation Index with Recurrence after Modified Radical Mastectomy for Breast Cancer: A Retrospective Cohort Study at Dr. Soetomo General Academic Hospital, Surabaya

Abstract

Recurrence after modified radical mastectomy (MRM) remains a major clinical problem in breast cancer, and simple, accessible prognostic markers are needed. Human epidermal growth factor receptor-2 (HER-2) status and the systemic immune-inflammation index (SII), calculated as platelet count × neutrophil count / lymphocyte count, have been proposed as prognostic markers, but evidence from Indonesian patients is scarce. This retrospective cohort study evaluated the association of HER-2 status and preoperative SII with recurrence in breast cancer patients who underwent MRM at Dr. Soetomo General Academic Hospital, Surabaya, between January 2018 and December 2023. Fifty-four patients with complete records were analysed (all women; mean age 53.35 ± 9.64 years; 64.8% with locally advanced disease; 51.9% HER-2 positive). Recurrence occurred in 14 patients (25.9%). Receiver operating characteristic (ROC) analysis showed poor discrimination of SII for recurrence (area under the curve [AUC] 0.587); the optimal cut-off of 362.29 gave a sensitivity of 85.71% but a specificity of only 37.5%. Recurrence occurred in 9 of 28 HER-2-positive patients (32.1%) and 5 of 26 HER-2-negative patients (19.2%) (Fisher’s exact test, p = 0.3582), and in 12 of 37 patients with high SII (32.4%) and 2 of 17 with low SII (11.8%) (p = 0.181). In multivariable logistic regression, neither HER-2 positivity (odds ratio [OR] 1.92, 95% CI 0.54–7.41; p = 0.319) nor high SII (OR 3.51, 95% CI 0.80–24.79; p = 0.133) was an independent predictor of recurrence. HER-2 status and SII were not significantly associated with recurrence in this cohort. The large but imprecise odds ratio for high SII suggests a possible prognostic role that should be tested in larger prospective studies using time-to-event analysis.