medwireNews: Appendiceal tumors occur at a high rate among patients with acute appendicitis and periappendicular abscess, with older age being a strong risk factor, concludes the Peri-APPAC-T study.
“These findings validate the previous alarming rates of appendiceal tumor rate associated with periappendicular abscess, which confirms that interval appendectomy after successful nonoperative treatment of periappendicular abscess should be the treatment paradigm in patients older than 35 years,” write Paulina Salminen (Turku University Hospital, Finland) and colleagues in JAMA Surgery.
A previous study by the same research group found that 20% of patients with periappendicular abscess developed appendiceal neoplasms. However, the study had a small number of patients, raising the need for a larger confirmatory study, say the researchers.
They studied 6165 consecutive patients at least 18 years of age with acute appendicitis who were treated with initial antibiotics and, if needed, drainage, followed by interval appendectomy at 3 months.
Of the total cohort, 3170 (51.4%) had uncomplicated acute appendicitis and 2995 (48.6%) had complicated acute appendicitis, including 2599 (86.8%) with appendicolith and/or perforation and 396 (13.2%) with periappendicular abscess.
The 370 patients with periappendicular abscess and available appendiceal histopathology had a median age of 58 years, a median BMI of 26.1 kg/m2, and 51.2% were men. They were significantly older than patients with uncomplicated acute appendicitis (median 37 years old) and complicated appendicitis without periappendicular abscess (median 46 years old).
The investigators observed that the 14.3% rate of appendiceal tumors in patients with periappendicular abscess was significantly higher than that in patients with uncomplicated appendicitis or complicated appendicitis without periappendicular abscess, with corresponding rates of 1.5% and 2.4%.
Salminen et al found that older patients were significantly more likely to develop periappendicular tumors, with an odds ratio of 1.06 per 1 year increase in age. The authors calculated a cutoff age of 35 years for predicting the prevalence of appendiceal tumors, with a sensitivity of 98.1% and specificity of 23.3%.
Using this threshold, only one appendiceal tumor in a younger patient would have been missed, they note, recommending that “all patients older than 35 years of age need to undergo interval appendectomy after initial successful conservative treatment.”
The authors add that “[f]or adult patients younger than 35 years of age, interval appendectomy should also be discussed with information about the tumor risk and recommended, but for asymptomatic patients younger than 35 years of age, interval surgery may not always be necessary.”
A total of 24.7% of patients with a periappendicular abscess experienced complications, with most being mild. This was reflected by 75% of the complications being grade I or II on the Clavien-Dindo classification, a measure of surgical complications ranging from I (mild) to V (death).
Salminen and colleagues found that emergency appendectomies were associated with significantly more complications than interval appendectomies, with respective rates of 31.3% and 4.8%. Also, 19.9% of the patients needed drainage in addition to antibiotics during the primary antibiotic treatment.
Of the 54 tumors in 53 patients, the most common were low-grade appendiceal mucinous neoplasms, followed by adenocarcinomas, adenomas, and neuroendocrine tumors, occurring at rates of 38.9%, 37.0%, 14.8%, and 9.3%, respectively. The most common tumors among patients with uncomplicated appendicitis were adenomas, while patients with complicated appendicitis without periappendicular abscess mostly had adenocarcinomas or neuroendocrine tumors.
In a linked editorial, Lawrence Lee and Liane Feldman, from McGill University in Montreal, Quebec, Canada, write that the study “adds further weight to arguments in favor of operative management.”
Regarding the proposed cutoff of 35 years, they note that, “[w]ith the increasing incidence of appendiceal cancer, particularly carcinoids in younger patients, one questions the prudence of any cutoff to recommend appendectomy, particularly in younger, fitter patients.”
They also comment that “[it] is ironic that in the era of shared decision-making, there may not be much of a decision to be made,” with appendectomy recommended in most cases of acute appendicitis.
“Whether it be due to the risk of recurrence, the high prevalence of appendiceal neoplasms, or other complications, the only remaining decision for most patients is whether to do it now or later,” they conclude.
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JAMA Surg 2025; doi:10.1001/jamasurg.2025.0312
JAMA Surg 2025; doi:10.1001/jamasurg.2025.0396