Causes of death in familial adenomatous polyposis

The prognosis in familial adenomatous polyposis (FAP) has improved over the past decades owing to a reduction in the prevalence of colorectal cancer, resulting from effective early screening. During the same period several polyposis registers have recorded an increasing number of deaths due to duodenal/periampullary cancer and desmoid tumours. The aim of this study was to examine the causes of death with special emphasis on duodenal/periampullary cancer.

The material consisted of 328 patients (144 females and 184 males) registered from I January 1943 to 31 December 1992 in the Danish Polyposis Register. The standard mortality rate (SMR) was calculated for known major causes of death, using the entire Danish population as background population. The attributable risk was also calculated for selected death causes.

One hundred and thirty-three patients had died, SMR being 4.98 (95% confidence limits, 4.17-5.90). There were significantly lower SMRs in the call-up group than in the proband group. The late cohort (1943-1992) had lower SMRs than the early group (1889-1942). SMR was significantly increased for death due to colorectal cancer (145), duodenal cancer (214), and ovarian cancer (30). No deaths due to desmoids were observed in the examination period. The attributable risk for colorectal cancer was 29% and for duodenal cancer only 0.6%.

Colorectal cancer is the most frequent cause of death in polyposis patients, followed by duodenal/periampullary cancer, but the latter is still a rare cause of death in FAP.