Long-term outcome of internal mammary lymph node detected by lymphoscintigraphy in early breast cancer

Purpose: Internal mammary lymph node (IMLN) metastasis is an important prognostic indicator in breast cancer. However, the necessity of internal mammary sentinel lymph node biopsy for accurate staging, for choosing adjuvant treatment, and as a prognostic indicator, has remained controversial.

Methods: From January 2001 to December 2006, 525 female breast cancer patients underwent radical surgery after preoperative lymphatic scintigraphy. We retrospectively analyzed the follow-up results, recurrences, and deaths of all patients.

Results: There was no significant difference in the clinicopathological characteristics between the axilla and the IMLN groups. The median follow-up period was 118.8 months (range, 7-122 months) in the axilla group and 107.7 months (range, 14-108 months) in the IMLN group. During the median follow-up period, the breast cancer-related death rate in the axilla group was 3.6%, which was not significantly different from that of the IMLN group (1.3%) (p=0.484). The five-year survival rates did not differ between the two groups (p=0.306). The overall recurrence rate and the locoregional recurrence rate also did not differ between the two groups (p=0.835 and p=0.582, respectively). The recurrence rate of IMLN (both ipsilateral and contralateral) metastasis was very low, accounting for 0.5% in the axilla group and 1.3% in the IMLN group (p=0.416).

Conclusion: The long-term follow-up results showed that there was no significant difference in both overall outcome and regional recurrence between the two groups. Therefore, the requirement for identification of nodal basins outside the axilla or IMLN sentinel biopsy should be reconsidered.