Appendiceal cancer masked as inflammatory appendicitis in the elderly, not an uncommon presentation (Surveillance Epidemiology and End Results (SEER)-Medicare Analysis)

Background: The misdiagnosis of appendiceal cancer as inflammatory appendicitis is becoming of greater clinical concern because of the rise of nonoperative management especially in the elder population. To quantify this rate of misdiagnosis, we retrospectively reviewed SEER-Medicare data. Methods: The SEER-Medicare database was reviewed from 2000 to 2014. We identified patients older than 65 years old who were diagnosed with appendiceal cancer and then cross-referenced them for a diagnosis of inflammatory appendicitis. Demographic data and oncologic stage were collected. Results: Our results showed that 28.6% of appendiceal cancer patients received an incorrect initial diagnosis of inflammatory appendicitis. Patients older than 75 years of age were more likely to be misdiagnosed than those between ages 65 and 75 (risk ratio [RR]: 0.81; 95% confidence interval: 0.70-0.93; P =.003). We found that 42% of patients within the misdiagnosis group presented with an earlier stage of disease (stage 1 or 2) compared to 26% of those primarily diagnosed with appendiceal cancer (P <.001). Conclusion: A significant proportion of patients older than 65 years old with appendiceal cancer were initially misdiagnosed with acute appendicitis. We suggest caution when considering a nonoperative approach for appendicitis in the elderly and follow-up imaging or an interval appendectomy should be part of the treatment plan.