Kim et al 2023 — Accessory Lymphatic Drainage Pathways in Breast Lymphedema
Memorial Sloan Kettering Cancer Center, retrospective review, Nov 2014–Dec 2020. Full text now obtained — quote below is confirmed verbatim, upgraded from no-access.
Verified findings
- 168 patients with unilateral upper-extremity breast cancer-related lymphedema; 30 (17.9%) had accessory lymphatic drainage pathways on ICG lymphography of the distal arm.
- Accessory-pathway group had significantly smaller limb volume differences (8.19% vs 20.74%, p<0.001) and lower MD Anderson ICG stage (p=0.0193) than those without.
- No significant demographic difference between groups (age, BMI, nodal surgery type, radiation, chemo) — the pathway itself, not patient factors, tracked with less swelling.
- Most common pattern: absence/re-routing of the radial bundle to the ulnar and/or volar bundles (n=16), or rerouting between bundles in the forearm/upper arm (n=16); 2 patients showed both.
- Discussion explicitly flags the same open mechanistic question as Kwon et al.: unclear whether these pathways represent true lymphangiogenesis or dilatation of pre-existing collaterals (the paper draws an analogy to varix dilation in portal hypertension and choke-vessel dilation in delayed TRAM flaps).
Verified verbatim quote
Confirmed against full text (Conclusions)
The ability to create accessory lymphatic drainage pathways may be associated with improved lymphatic drainage, resulting in smaller limb volumes. Furthermore, certain drainage pathways appear to be more common than others. Description of these pathways should be considered for inclusion in ICG lymphography image grading criteria. Further study is needed [to] clarify the nature of these pathways, and whether these pathways affect subjective symptomology and patient quality of life.
New leads surfaced from this paper’s discussion
Only 4 studies (per the authors) have reported accessory pathway formation at all — worth acquiring the other two we don’t yet have:
- Tashiro K, et al. “Visualization of Accessory Lymphatic Pathways in Secondary Upper Extremity Lymphedema Using Indocyanine Green Lymphography.” Ann Plast Surg 2017;79:393–396.
- Tashiro K, et al. “Indocyanine Green Lymphographic Signs of Lymphatic Collateral Formation in Lower Extremity Lymphedema After Cancer Resection.” Ann Plast Surg 2016;77:213–216.
- Mihara M, et al. J Plast Reconstr Aesthet Surg 2013;66:e338–340 — the only one of the four with histochemical confirmation (podoplanin-positive vessels) of true new lymphatic growth after VLNT, rather than inferred from imaging alone.
My take
Directly useful for the mechanism paragraph: gives a real percentage (17.9%) for how often accessory/collateral pathways form after axillary disruption, and explicitly poses the same unresolved lymphangiogenesis-vs-dilatation question our case’s Discussion will need to address (and duck, appropriately, given we have no histology of the aberrant channel itself — only Mihara et al. has that).