Breast cancer continues to represent a major global health burden and is a leading contributor to cancer-related mortality among women. Locally advanced breast cancer encompasses tumors with extensive local spread, including significant nodal involvement or invasion of adjacent structures[1].

Despite advances in systemic therapy, ALND remains a key component for regional disease control and staging. However, its association with postoperative complications—particularly lymphedema—has prompted exploration of less morbid alternatives[2].

Axillary Reverse Mapping (ARM) is based on the concept of preserving lymphatic channels draining the upper limb during axillary surgery. While technically feasible, concerns persist regarding oncological safety due to possible overlap between breast and arm lymphatic pathways[3].

This study was conducted to evaluate the incidence of metastatic involvement in ARM nodes in patients undergoing surgery following neoadjuvant chemotherapy.

AIMS AND OBJECTIVES

Primary Objectives:

1. To identify ARM lymph nodes intraoperatively during ALND
2. To determine the rate of metastatic involvement in these nodes
3. To assess their relevance in predicting axillary disease status

Secondary Objective:

To examine the relationship between ARM node involvement and clinicopathological factors

MATERIALS AND METHODS

Study Design: Cross-sectional observational study

Setting: Department of General Surgery, MY Hospital, Indore

Sample Size: 75 patients

INCLUSION CRITERIA:

• Female patients aged >18 years
• Diagnosed with LABC
• Completed neoadjuvant chemotherapy
• Planned for modified radical mastectomy with ALND

PROCEDURE:

A volume of 2–4 ml methylene blue dye was injected into the ipsilateral upper limb prior to surgery. During axillary dissection, blue-stained lymphatics and nodes were identified as ARM nodes. These were excised separately and sent for histopathological analysis independent of standard axillary specimens.

STATISTICAL ANALYSIS:

Data were analyzed using JAMOVI software. Associations between categorical variables were evaluated using Chi-square test, while continuous variables were analyzed using unpaired t-test. A p-value <0.05 was considered statistically significant.

RESULTS:

Table 01: Age distribution of the patients

There is a statistically significant difference in the distribution of participants across age groups (p ≈ 0.002). The majority of participants were concentrated in the 41–50 and 51–60 age groups, indicating that the sample is not evenly distributed across all age categories.

Table 02: Clinical Characteristics of Patients Included in the Study

Tumor sites are not evenly distributed. There is a clear predominance of tumors in certain locations. Most common site: Upper Outer Quadrant (40%)

Least common: Lower Inner Quadrant (6.7%). There is a highly statistically significant difference in the distribution of tumor sites. The upper outer quadrant was the most commonly affected site, indicating a non-uniform distribution of tumor location among the study participants. Chi-square goodness-of-fit test applied.

All 75 patients (100%) received neoadjuvant chemotherapy, while none (0%) did not receive it.This indicates complete uniformity in treatment every subject in the study was given neoadjuvant chemotherapy.The p-value is extremely small (< 0.05). This means the distribution of patients across clinical stages is not equal. There is a statistically significant difference, with most patients concentrated in Stage III

Table 03: Operative and Histopathological Parameters of Patients in Whom ARM Node(s)/Lymphatics identified

For “Number of ARM Nodes,” percentages are based on total 75 patients; the sum (60) equals the number with nodes identified. All patients (100%) underwent MRM.There was a statistically significant difference in ARM node identification, with a higher proportion of patients showing identifiable ARM nodes (80%). There was a statistically significant difference in ARM lymphatic identification (χ² = 16.33, p < 0.0001), with most patients showing identifiable lymphatics (73.3%). There was a statistically significant predominance of patients with both ARM node and lymphatic identified.There was no statistically significant difference in the distribution of the number of ARM nodes identified.

Table 04: Correlation of ARM Nodes/Lymphatics Identification with Clinicopathological Parameters

All totals sum to 75 patients (60 ARM identified, 15 not identified).

Age: Among patients aged <50 years, ARM nodes were identified in 38 cases compared to 22 cases in those ≥50 years. However, this difference was not statistically significant (p ≈ 0.25), indicating that age did not influence ARM identification.

Tumor Size: ARM nodes were identified in 15 patients with T1–T2 tumors and 45 patients with T3–T4 tumors. The association was not statistically significant (p ≈ 0.57), suggesting tumor size had no significant effect on ARM identification.

Nodal Status: In node-negative (N0) patients, ARM nodes were identified in 32 cases, while in node-positive (N+) patients, 28 cases showed identification. This difference was also not statistically significant (p ≈ 0.41).

Stage: ARM identification was seen in 20 early-stage and 40 advanced-stage patients. The p-value (≈ 0.049) indicates a statistically significant association, suggesting that stage may influence ARM node identification. However, the Chi-square value reported (≈ 0.00) appears inconsistent with the p-value and may require verification.

Histological Grade: ARM nodes were identified across all grades (Grade I: 8, Grade II: 28, Grade III: 24), with no statistically significant association (p ≈ 0.97), indicating tumor grade does not affect ARM identification.

Table 05: ARM Nodes of Identified

The p-value is highly significant (< 0.05)

This means the observed distribution is not equal.There are significantly more negative ARM nodes (82%) than positive (18%).

Table 06: Correlation of identified ARM Nodes metastatic involvement with Clinicopathological Parameters

All totals sum to 75 patients (60 ARM identified, 15 not identified).

Age: Out of 38 patients aged <50 years, 6 (15.8%) had metastatic ARM nodes, whereas among 22 patients aged ≥50 years, 5 (22.7%) showed positivity.

This difference was not statistically significant (χ² ≈ 0.7, p > 0.05).

Tumor Size: Among C T1–T2 tumors 2 (13.3%) had metastatic ARM nodes, compared to 9 (20.0%) in 45 patient with T3–T4 tumors .The association between tumor size and ARM node metastasis was not statistically significant (χ² ≈ 0.3, p > 0.05)..

Nodal Status: Among 32 node-negative patients (N0), 3 (9.4%) had metastatic ARM nodes, whereas in 28  node-positive patients (N+), 8 patients (28%) showed involvement.

Although a higher proportion was observed in node-positive cases, the association was statistically significant (χ² ≈ 3.57, p < 0.05).

Stage: Among early-stage patients (n=20), 1 (5%) had metastatic ARM nodes, compared to 10 (25%) among advanced-stage patients (n=40).

This difference was found to be statistically significant (χ² ≈ 4.2, p ≈ 0.04).

Histological Grade: Metastatic ARM node involvement was observed in  1 patient with Grade 1 tumor(n=8), 4 patients with Grade 2 tumor(n=28), 6 patients with Grade 3 tumor(n=24)

Although a rising trend was seen with increasing tumor grade, the association was not statistically significant (χ² ≈ 2.0, p > 0.05).

DISCUSSION

The present study demonstrates that ARM nodes may harbor metastatic disease in a notable subset of patients with LABC [4-6]. The observed rate of 18% falls within the range reported in existing literature [7]. These findings indicate that lymphatic drainage pathways of the breast and upper limb are not entirely distinct, supporting the concept of anatomical crossover [8]. Patients with higher nodal burden and advanced stage appear more likely to exhibit ARM node involvement [9]. Although neoadjuvant chemotherapy reduces tumor load, it may not completely eradicate microscopic disease within lymphatic channels. Therefore, preservation of ARM nodes without assessment could potentially leave residual disease [10].

CONCLUSION

ARM technique shows a high identification rate and is technically feasible. Metastatic involvement in ARM nodes is not negligible. Routine preservation of ARM nodes in LABC is not advisable. Selective preservation guided by intraoperative or pathological assessment may improve safety.

LIMITATIONS

• Single-center design limits generalizability
• Lack of long-term follow-up data
• Survival and recurrence outcomes were not evaluated

Declaration by Authors

• Ethical Aproval: Approved
• Acknowledgement: None
• Source of Funding: None
• Conflict of interest: The Authors declare no conflict of interest.

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