Emergency presentation of colon cancer is most frequent during summer

Aim The frequency of emergency colon cancer (ECC) was determined using a reproducible definition of 'emergency' to analyse the impact of mode of presentation on long-term prognosis and to search for risk factors for an emergency presentation. Method All patients with colon cancer treated at one Swedish GDH between 1996 and 2005 (N = 604) were eligible. Patients admitted through the emergency room, operated on within three days and with an emergency condition confirmed at surgery were classified as ECC. Survival was analysed by Kaplan-Meier estimates and risk of death by Cox regression. Results The rate of ECC was 97/585 (17%). Patients with ECC were older (median 77 vs 74, P = 0.02), they had more stage III and IV cancers (65% vs 47%; chi 2 = 9.4, P < 0.001) and had a cancer located in the caecum less often (20% vs 33%, chi 2 = 4.3 P = 0.04). ECC were most frequent between June and August (36%), whereas elective cases were evenly distributed throughout the year (chi 2 = 7.8; P = 0.049), Crude 5-year survival was 18% in ECC and 38% in the elective group (P < 0.001). The hazard ratio for death within five years in ECC, with 30-day mortality excluded and adjusted for age and sex was 2.25 (95% CI; 1.42-3.55). Conclusion Emergency presentation of colon cancer is an independent and adverse risk factor for long-term survival. The causes of a seasonal variation need to be clarified.