Limited value of staging squamous cell carcinoma of the anal margin and canal using the sentinel lymph node procedure: a prospective study with long-term follow-up.
BACKGROUND
Selection of patients with anal cancer for groin irradiation is based on tumor size, palpation, ultrasound, and fine needle cytology. Current staging of anal cancer may result in undertreatment in small tumors and overtreatment of large tumors. This study reports the feasibility of the sentinel lymph node biopsy (SLNB) in patients with anal cancer and whether this improves the selection for inguinal radiotherapy.


METHODS
A total of 50 patients with squamous anal cancer were evaluated prospectively. Patients without a SLNB (n = 29) received irradiation of the inguinal lymph nodes based on lymph node status, tumor size, and location of the primary tumor. Inguinal irradiation treatment in patients with a SLNB was based on the presence of metastases in the SLN.


RESULTS
SLNs were found in all 21 patients who underwent a SLNB. There were 5 patients (24%) who had complications after SLNB and 7 patients (33%) who had a positive SLN and received inguinal irradiation. However, 2 patients with a tumor-free SLN and no inguinal irradiation developed lymph node metastases after 12 and 24 months, respectively.


CONCLUSIONS
We conclude that SLNB in anal cancer is technically feasible. SLNB can identify those patients who would benefit from refrain of inguinal irradiation treatment and thereby reducing the incidence of unnecessary inguinal radiotherapy. However, because of the occurrence of inguinal lymph node metastases after a tumor-negative SLNB, introduction of this procedure as standard of care in all patients with anal carcinoma should be done with caution to avoid undertreatment of patient who otherwise would benefit from inguinal radiotherapy.
de Jong
Johannes S
JS
Department of Surgery, Division of Surgical Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. j.s.dejong@chello.nl
Beukema
Jannet C
JC
van Dam
Gooitzen M
GM
Slart
Riemer
R
Lemstra
Clara
C
Wiggers
Theo
T
D000230:Adenocarcinoma / Q000473:pathology* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001003:Anal Canal / Q000473:pathology* / Q000601:surgery; D001005:Anus Neoplasms / Q000473:pathology* / Q000601:surgery; D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000601:surgery; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*; D015996:Survival Rate