The Prevalence of Appendiceal Tumours in Periappendicular Abscess

Summary

Complicated and uncomplicated appendicitis follow different epidemiological trends also suggesting different pathophysiology behind these two different forms of appendicitis. In 3-10% of patients complicated acute appendicitis is enclosed by formation of a circumscribed periappendicular abscess. The clinically established practice of antibiotic therapy and drainage, if necessary, has been shown safe and effective, allowing the acute inflammatory process to subside in more than 90% of cases without surgery. The need of subsequent interval appendectomy has been questioned with appendicitis recurrence risk varying between 5-26%.

During trial enrollment in our randomized Peri-APPAC trial based on the interim analysis results with 17% appendiceal tumor rate in the study population, the trial was prematurely terminated based on ethical concerns. All the follow-up group patients were re-evaluated and surgery was offered and recommended to all follow-up group patients. After this assessment and additional appendectomies, two more tumors were diagnosed resulting in neoplasm rate of 20% in the whole study group all diagnosed in patients over 40 years and the neoplasm rate in patients over 40 years was 29%.

Based on high appendiceal tumor rate in patients over 40 years, the appendiceal neoplasm rate needs to be further evaluated in prospective patient cohorts undergoing interval appendectomy as interval appendectomy is generally well tolerated and obliterates the risk of missing a possible tumor. In a recent systematic review of retrospective cohort studies with 13.244 acute appendicitis patients the overall appendiceal tumor rate was 1% after appendectomy, but in patients presenting with appendiceal inflammatory mass the neoplasm rate varied from 10% to 29%.

This nationwide prospective multicenter cohort study is designed to assess the prevalence of appendiceal tumors associated with a periappendicular abscess. All consecutive patients presenting with a periappendicular abscess are recommended to undergo interval appendectomy after initial conservative treatment with antibiotic therapy and drainage, if necessary. All patients older than 35 years will undergo laparoscopic interval appendectomy at 2 to 3 months and this is also recommended for the patients between 18 and 35 years of age. Asymptomatic patients under 35 years not willing to undergo interval appendectomy, will undergo a follow-up MRI at 1 year after the initial non-operative treatment.

Conditions

• Appendix Abscess
• Appendicitis
• Appendix Mass
• Appendix Cancer
• Appendix Nec
• Appendix Tumor
• Appendix Diseases

Interventions

PROCEDURE

Interval appendectomy

interval appendectomy at 2 to 3 months after the initial non-operative treatment

DIAGNOSTIC_TEST

Follow-up MRI at 1 year

follow-up MRI at 1 year for asymptomatic patients under 35 years of age not wanting to undergo surgery

Sponsors & Collaborators

• Oulu University Hospital

  collaborator OTHER

• Tampere University Hospital

  collaborator OTHER

• Kuopio University Hospital

  collaborator OTHER

• Jyväskylä Central Hospital

  collaborator OTHER

• Mikkeli Central Hospital

  collaborator OTHER

• Lapland Central Hospital

  collaborator UNKNOWN

• Vaasa Central Hospital, Vaasa, Finland

  collaborator OTHER

• Seinajoki Central Hospital

  collaborator OTHER

• North Karelia Central Hospital

  collaborator OTHER

• South Carelia Central Hospital

  collaborator OTHER

• Päijänne Tavastia Central Hospital

  collaborator OTHER

• Satakunta Central Hospital

  collaborator OTHER

• Turku University Hospital

  lead OTHER_GOV

Principal Investigators

• Paulina Salminen, prof, MD · Turku University Hospital

Study Design

Allocation

NON_RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2020-12-01

Primary Completion

2022-12-31

Completion

2035-12-31