Evaluation of long-term treatment outcomes and quality of life in patients with early-stage (CT1–2CN0) Breast cancer depending on the extent of surgical treatment

Introduction: Breast cancer (BC) remains the most common oncological disease among women, with the majority of cases diagnosed at early stages (I–II), supporting the use of breast-conserving approaches. The status of axillary lymph nodes is a key factor in determining the extent of surgical treatment. Although sentinel lymph node biopsy (SLNB) is considered the standard method for nodal staging in clinically node-negative (cN0) patients, data from major studies (ACOSOG Z0011, SOUND, INSEMA, BOOG 2013–08) support the safety of omitting SLNB in selected cT1–2N0 patients undergoing systemic therapy and active surveillance. In addition to comparable oncologic outcomes, SLNB omission is associated with a lower rate of postoperative complications and improved quality of life. This study aimed to evaluate long-term oncological outcomes and QoL in patients with cT1–2cN0 luminal BC undergoing breast-conserving surgery with or without sentinel lymph node biopsy.
Objective: To assess long-term oncological outcomes and quality of life in patients with cT1–2cN0 breast cancer depending on the extent of axillary surgical intervention.
Material and Methods: This retrospective study was conducted at the P.A. Hertsen National Medical Research Center of Oncology between 2017 and 2022 and included 204 patients with luminal subtypes of primary operable breast cancer (cT1–2N0). All patients had confirmed pN0 status by pathology, underwent breast-conserving surgery, and received adjuvant 
radiotherapy and hormone therapy. Patients were divided into two groups:
Group I (n=51): patients who did not undergo axillary surgery (no SLNB);
Group II (n=153): patients who underwent SLNB with histologically confirmed pN0 status.
Groups were matched using pseudo-randomization at a 1:3 ratio based on clinicopathological tumor characteristics. The median age of patients was 58.1 years [49.6–65.3]; 59.1 [51.2–66.0] in Group I. Stage IA was diagnosed in 164 patients (80.4%) and stage IIA in 40 patients (19.6%). In Group I, 79.5% had tumors in the left breast. Metachronous tumors and multicentric growth were observed in 11.8% (n=6) of Group I and in 7.8% of the total cohort. Invasive ductal carcinoma was found in 84.8% (n=173) of all patients and in 82.4% (n=42) of Group I. The luminal A subtype was observed in 73% (n=149) of patients overall and in 82.4% (n=42) of Group I. Moderately differentiated tumors were found in 89.7% of the total cohort and 92.2% in Group I. Quality of life was assessed using the validated EORTC QLQ-BR23 questionnaire over a 12-month postoperative period. Primary endpoints included arm/shoulder pain, edema, and mobility restriction. Statistical analysis was performed using SPSS v.21 and Statistica v.10 with χ², Fisher’s exact test, Mann–Whitney U test, and Kaplan–Meier analysis. A significance level of p<0.05 was applied.
Results: The median follow-up was 76.8 months [64.6–81.4], ranging from 12.1 to 96.3 months. Disease progression was observed in 4.4% (n=9) of patients: 5.9% in Group I and 3.9% in Group II. Regional recurrences were reported in 1.5% (n=3) of all cases: 3.9% (n=2) in Group I and 0.7% (n=1) in Group II (p=0.155). One local recurrence occurred in Group II. Distant metastases were identified in 2.5% (n=5) of patients. Median progression-free and overall survival were not reached. Five-year overall survival (OS) was 100% in both groups. Five-year progression-free survival (PFS) was 95.2 ± 3.4% in Group I and 98.0 ± 1.1% in Group II, with no statistically significant difference (p > 0.05). QoL assessment revealed statistically significant differences in the frequency and severity of functional impairments of the upper limb. According to EORTC QLQ-BR23, arm/shoulder symptoms were reported in 4% of Group I and 17% of Group II (p=0.012). In Group I, all symptoms were graded as «mild», while in Group II, 2–3.3% of patients reported them as «significant».
Conclusion: Our study confirms that patients with cT1–2 cN0 luminal breast cancer can be considered candidates for omission of sentinel lymph node biopsy. This approach does not compromise oncological treatment efficacy and is associated with more favorable quality-of-life outcomes, including a lower incidence of postoperative upper limb complications.