Twelve studies were included in the review: 10 retrospective studies (n=1,302) and two population analyses from the SEER database (n=35,765 assuming no overlap of patients). Median follow-up (where reported) ranged from 18 months until the patient's death.
Perioperative mortality rates in the retrospective studies ranged from 1.3% to 11.7% with a median rate of 4.6% (eight studies). The postoperative mortality rate was reported to range from 9.5% to 42.7% with a median rate of around 20% (number of studies unclear). There was limited evidence to suggest that operative mortality from the resection of tumours that became symptomatic was lower than that reported following emergent surgery (three studies). Median survival rates for the analyses that compared surgery to no surgery were 10.6 months to 16 months and two to 16.6 months.
Two comparative studies with results in favour of surgery showed a statistically significant survival benefit in asymptomatic patients (HR 0.50, 95% CI 0.27 to 0.90) reported in one of the studies, but the difference was no longer significant when perioperative mortality was taken into account. Survival in the other study was 16 months versus nine months (p<0.001).
One comparative study of symptom development between surgical and non-surgical patients found that there were no statistically significant differences between the groups in terms of newly incident obstruction, haemorrhage that required admission, peritonitis and fistulisation.
Details of the potential impact of various patient and tumour characteristics were reported in the paper.