Sentinel node mapping in anal canal cancer: systematic review and meta-analysis.
OBJECTIVE
The pathological condition of inguinal lymph nodes is an independent prognostic factor in predicting tumor recurrence and overall survival in anal canal cancer. Sentinel node mapping is a non-invasive method for the detection of inguinal lymph node involvement in anal cancer. In the current study, we conducted a comprehensive search of literature in this regard and then interpreted the final results in a systematic review and meta-analysis format.


METHODS
Medline, SCOPUS, and ISI Web of Knowledge were searched with the following search terms: (anal OR anus) AND sentinel. Outcomes of interest were inguinal detection rate and inguinal recurrence in patients receiving inguinal sparing radiotherapy due to pathologically negative inguinal sentinel nodes (false negative cases).


RESULTS
Overall 16 studies (323 patients) were included in the meta-analysis. Pooled inguinal detection rate was 86.2%: 73.4-93.4%: for studies using both blue dye and radiotracer it was 90.1% [78.7-95.8] and for studies using radiotracer alone it was 72.4% [46.3-88.9]. Pooled sensitivity was 90% [79-97%].


CONCLUSIONS
Sentinel node biopsy is a promising method for inguinal lymph node staging in anal cancer. Combined blue dye and radiotracer technique can maximize the inguinal detection rate. Location of the tumor is highly associated with the detection of inguinal sentinel nodes. Despite fairly high pooled sensitivity, no definite conclusion can be made regarding false negative rate of this technique due to low sample size and sub-optimal quality of the included studies. Large multicenter studies with long and consistent follow up are needed to definitely validate this technique in the future.
Nuclear Medicine Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; Email: Sadeghir@mums.ac.ir.
Shahrzad
S
Tehranian
Giorgio
G
Treglia
David N
DN
Krag
Vahid Reza
VR
Dabbagh Kakhki
Seyed Rasoul
SR
Zakavi
Ramin
R
Sadeghi
Mohamed
M
Keshtgar
D001005:Anus Neoplasms / Q000473:pathology*; D004396:Coloring Agents; D004395:Dye Dilution Technique; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D021701:Sentinel Lymph Node Biopsy
D004396:Coloring Agents