High neoplasm rate seen after conservative treatment of periappendicular abscess

Last Updated: 2018-12-03

By Marilynn Larkin

NEW YORK (Reuters Health) - A trial comparing interval appendectomy to MRI follow-up after nonoperative treatment of periappendicular abscess was stopped prematurely after an interim analysis revealed a high neoplasm rate.

"The number of appendiceal tumors detected at interval appendectomy was alarming, and this is why the study was prematurely terminated due to ethical reasons," Dr. Paulina Salminen of Turku University Hospital in Finland told Reuters Health.

"Periappendicular abscess is a form of complicated acute appendicitis that has already initially been treated conservatively, which is different from all other forms of complicated acute appendicitis (for example, perforated acute appendicitis)," she said by email. "The controversy with periappendicular abscess has been the need for interval - i.e., planned elective - appendectomy later on, after the initial successful conservative treatment."

Dr. Salminen's team had previously shown that antibiotic therapy can be effective as an initial treatment for acute uncomplicated appendicitis, with a five-year recurrence rate of 39%. (http://bit.ly/2IfaxmE).

For the current study, the team enrolled 60 patients (median age about 48; 60% men) who were diagnosed with periappendicular abscess in the emergency departments of five hospitals in Finland. Patients were randomized to either laparoscopic appendectomy or follow-up examinations with abdominal MRI. Both interventions were scheduled approximately three months after randomization.

As reported online November 28 in JAMA Surgery, a clinical suspicion of increased neoplasm risk among participants led to an unplanned interim analysis. The analysis revealed a 17% rate of neoplasms, with all cancers found in patients over age 40. The trial was terminated prematurely because of ethical concerns. Subsequently, two more neoplasms were diagnosed, resulting in an overall incidence of 20%.

At termination, the postoperative complication rate was 10% in the interval appendectomy group, and 33% of patients in the MRI follow-up group had undergone appendectomy at intervals ranging from 18 to 332 days.

Dr. Salminen said, "If this significant rate of neoplasms after periappendicular abscess is validated by future studies, it would argue (in favor of) routine interval appendectomy in this setting. We are planning on performing a prospective cohort study of periappendicular abscess patients in order to assess the associated neoplasm rate in a prospective national patient cohort."

"What we can learn from (all) the data is that with acute uncomplicated appendicitis, laparoscopic appendectomy performed within 24 hours allows for same-day discharge of the patient and very few adverse events. This approach will also eliminate the doubt and risks associated with an incidental appendiceal tumor," Dr. Kamal M.F. Itani of Boston University School of Medicine and the VA Boston Health Care System, told Reuters Health.

"This approach should be the gold standard against which any other intervention is measured for treatment failure, hospital length of stay, readmissions, complications, quality of life and costs," he said by email.

By contrast, "for perforated appendicitis, after addressing the abscess, an interval appendectomy should be the standard of care," Dr. Itani said. "A 20% rate of undetected tumor if appendectomy is not performed is unacceptable."

"In the event a patient is treated with antibiotics for uncomplicated or complicated appendicitis as definitive early therapy either because of patient's choice or severe comorbidities, I recommend an interval appendectomy or close follow up to rule out the possibility of an appendiceal tumor," he concluded.

SOURCE: http://bit.ly/2Rw6tCt and http://bit.ly/2RwSLzc

JAMA Surg 2018.