Recurrences in the internal mammary lymph nodes (IMLN) are very rare, despite the fact that these nodes remain untreated in most patients. The aim of this study was to assess the chance for IMLN recurrence in a large patient series and to get insight into diagnostics, treatment and prognosis of this type of recurrence. Follow-up of nearly 6000 breast cancer patients resulted in the tracing of only six patients with IMLN recurrence. IMLN recurrence was defined as breast cancer recurrence in an internal mammary lymph node without a distant metastasis before the recurrence and confirmed by cytology and/or CT-scan. The time interval between diagnosis of the primary tumor and the recurrence varied between 5 months and 8 years and 6 months. One patient showed no symptoms, the other five all had a swelling and one of them also had pain. The size of the parasternal swelling varied from 30 to 90 mm; in one patient the size was unknown. Treatment resulted in a complete remission in four patients. In five of the six patients distant metastases occurred. The time interval between IMLN recurrence and the diagnosis of distant metastasis varied between 0 and 37 months. One patient was still free of distant metastasis in the time of this study. This large population-based study confirms the almost negligible risk of clinically apparent IMLN recurrence. Considering the high percentage of positive lymph nodes in studies evaluating sentinel node biopsy of the internal mammary chain, it becomes clear that just a fraction of these becomes clinically apparent as a recurrence. In almost all patients with IMLN it is a forerunner of metastatic disease.
Cranenbroek, S., Van der Sangen, M. J. C., Kuijt, G. P., & Voogd, A. C. (2005). Diagnosis, treatment and prognosis of internal mammary lymph node recurrence in breast cancer patients. Breast Cancer Research and Treatment, 89(3), 271-275. https://doi.org/10.1007/s10549-005-2469-y