Comparison of positron emission tomography scanning and sentinel node biopsy in the detection of inguinal node metastases in patients with anal cancer.
BACKGROUND
Inguinal lymph node metastases in patients with anal cancer are an independent prognostic factor for local failure and overall mortality. Inguinal lymph node status can be adequately assessed with sentinel node biopsy, and the radiotherapy strategy can subsequently be changed. We compared this technique vs. dedicated 18F-fluorodeoxyglucose positron emission tomography (PET) to determine which was the better tool for staging inguinal lymph nodes.


METHODS
In our department, 27 patients (9 men and 18 women) underwent both inguinal sentinel node biopsy and PET-CT. PET-CT was performed before treatment and then at 1 and 3 months after treatment.


RESULTS
PET-CT scans detected no inguinal metastases in 20 of 27 patients and metastases in the remaining 7. Histologic analysis of the sentinel lymph node detected metastases in only three patients (four PET-CT false positives). HIV status was not found to influence the results. None of the patients negative at sentinel node biopsy developed metastases during the follow-up period. PET-CT had a sensitivity of 100%, with a negative predictive value of 100%. Owing to the high number of false positives, PET-CT specificity was 83%, and positive predictive value was 43%.


CONCLUSIONS
In this series of patients with anal cancer, inguinal sentinel node biopsy was superior to PET-CT for staging inguinal lymph nodes.
Mistrangelo
Massimiliano
M
Department of Surgery, University of Turin, Turin, Italy. mistrangelo@katamail.com
Pelosi
Ettore
E
Bellò
Marilena
M
Castellano
Isabella
I
Cassoni
Paola
P
Ricardi
Umberto
U
Munoz
Fernando
F
Racca
Patrizia
P
Contu
Viviana
V
Beltramo
Giancarlo
G
Morino
Mario
M
Mussa
Antonio
A
D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001005:Anus Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000473:pathology* / Q000532:radiotherapy; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy; D003131:Combined Modality Therapy / Q000379:methods; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007264:Inguinal Canal; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis / Q000175:diagnosis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18