Extensive surgery and lymphadenectomy do not improve survival in primary melanoma of the anorectum: results from analysis of a large database (SEER).
OBJECTIVE
Primary anorectal melanoma is a rare disease with a dismal prognosis due to early distant metastasis. The prognostic value of positive loco-regional lymph nodes and the impact of lymphadenectomy on overall survival are unclear. We have investigated this by analysis of data obtained from a national representative database, controlling for potential confounders.


METHODS
Data were retrieved from the Surveillance, Epidemiology and End Results (SEER) database. Multiple imputation analysis was performed to deal with missing data. Cox regression models were formulated using different prognostic factors including site of origin, gender, size, race, rate of lymph node metastasis (ratio between positive lymph node count and total lymph nodes harvested), extent of lymphadenectomy (none, level I etc.), age, type of surgery, stage of disease and administration of radiotherapy.


RESULTS
Our population was composed of 208 patients who underwent surgery between 1998 and 2012. Rate of lymph node metastasis (P = 0.027; hazard ratio 1.873, 95% CI 1.076-3.261) and race (P = 0.019; hazard ratio 2.291, 95% CI 1.148-4.575) were found to be independent predictors of survival.


CONCLUSIONS
Based on the data retrieved from the SEER database, metastasis to loco-regional lymph nodes is an important prognostic factor, but lymphadenectomy does not improve survival.
General and Emergency Surgery, University of L'Aquila, L'Aquila, Italy.
A
A
Ciarrocchi
Coloproctological Surgery University of L'Aquila, Hospital Val Vibrata, Sant'Omero (TE), Italy.
R
R
Pietroletti
Postgraduate School of Digestive Surgery, University of L'Aquila, L'Aquila, Italy.
F
F
Carlei
General and Emergency Surgery, University of L'Aquila, L'Aquila, Italy.
G
G
Amicucci
D000368:Aged; D001005:Anus Neoplasms / Q000401:mortality / Q000601:surgery*; D013505:Digestive System Surgical Procedures / Q000379:methods*; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008545:Melanoma / Q000401:mortality / Q000601:surgery*; D008875:Middle Aged; D016016:Proportional Hazards Models; D012004:Rectal Neoplasms / Q000401:mortality / Q000601:surgery; D018426:SEER Program; D015996:Survival Rate
Anorectal melanoma; malignant melanoma; tumour of the rectum