Upstaging of early colorectal cancers following improved lymph node yield after methylene blue injection.
OBJECTIVE
To evaluate whether the use of intra-arterial methylene blue injection improves lymph node yield, and to determine whether a higher lymph node count results in upstaging in colorectal cancer.


RESULTS
We performed a retrospective study of colorectal cancer specimens (n = 234) 1 year after implementation of the method. All colorectal cancer specimens from the previous year served as our control group. Data concerning tumour characteristics, lymph node count, number of positive lymph nodes and success of methylene injection had been prospectively collected in accordance with the department's ongoing registration. The method was easy to implement and perform with a high rate of success (86%). The number of identified lymph nodes was highly significantly improved in the study group (P < 0.0001). In resections with pT1/T2 tumours, we demonstrated a significant increase in the number of resection specimens containing positive lymph nodes, with an increase in pN1 resections from 9.4% in the control group to 26.7% in the study group (P = 0.04).


CONCLUSIONS
THE methylene blue technique significantly improves lymph node identification in colorectal cancer specimens, and the improved lymph node identification leads to upstaging of International Union Against Cancer (UICC) pT1/pT2 cancers.
Department of Pathology, Rigshospitalet, Copenhagen, Denmark.
Rikke Karlin
RK
Jepsen
Peter
P
Ingeholm
Eva Løbner
EL
Lund
D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000556:secondary; D004396:Coloring Agents / Q000008:administration & dosage; D005260:Female; D006801:Humans; D015552:Injections, Intralesional; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis / Q000473:pathology*; D008297:Male; D008751:Methylene Blue / Q000008:administration & dosage*; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D012189:Retrospective Studies
D004396:Coloring Agents; D008751:Methylene Blue