[Adenocarcinoma of the appendix in Iceland 1990-2009. A population based study].

Objective: Adenocarcinoma of the appendix is less than 0.5% of all gastrointestinal cancers. The aim of this study was to analyse the incidence, symptoms, pathology and treatment of appendiceal adenocarcinoma in a well defined cohort as well as the prognosis of the patients.

Materials And Methods: This is a retrospective study on all patients diagnosed with adenocarcinoma of the appendix in Iceland from 1990-2009. Information on epidemiological factors, survival and treatment was collected. All histological material was reviewed. Overall survival was estimated with median follow up of 15 months (range, 0-158).

Results: A total of 22 patients were diagnosed with appendiceal adenocarinoma in the study period (median age 63 yrs, range: 30-88, 50% males). Age-standardized incidence was 0.4/100,000/year. The most common symptom was abdominal pain (n=10). Eight patients had clinical signs of appendicitis. Most patients were diagnosed at operation or at pathological examination but one patient was diagnosed at autopsy. Five patients had an appendectomy and 11 a right hemicolectomy. One patient was not operated on and in three patients only a biopsy was taken. Twelve patients had chemotherapy and seven of them for metastatic disease. Eight patients had adenocarcinoma, seven mucinous adenocarcinoma, three signet ring adenocarcinoma, one mixed goblet cell carcinoid and mucinous adenocarcinoma,one mixed adenocarcinoma and signet ring adenocarcinoma and two a mucinous tumour of unknown malignant potential. In eight cases the tumor originated in adenoma. Most of the patients had a stage IV disease (n=13), three stage III, three stage II and three stage I. Operative mortality was 4.8% (n=1). Disease specific five year survival was 54% but overall five year survival was 44% respectively.

Conclusion: Adenocarcinoma of the appendix is a rare disease. No patients were diagnosed pre-operatively. Over half of the patients presented with stage IV disease.