Appendix cancer diagnostic study of choice

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Soroush Seifirad, M.D.[2]

Overview

Either CT-scan or MRI are diagnostic study of choice for appendix cancer. Both MRI (particularly diffusion weighted MRI) and CT scan has been recommended as method of choice for disease staging. Histopathology is the gold standard test for the diagnosis as well as classification of appendix cancers.

Peritoneal carcinomatosis index (PCI) using either CT-scan or preferably diffusion weighted MRI has been globally accepted to determine disease burden in appendix cancer.

Histopathology is the gold standard test for the diagnosis as well as classification of appendix cancer.

Among the patients who present with clinical signs of carcinoid syndrome, somatostatin scintigraphy with 111-indium-octreotide and serum 5-HIAA levels are the most specific tests for the diagnosis.
Among the patients who present with clinical signs of appendicitis, the CT-scan is the most sensitive test for diagnosis.

Peritoneal carcinomatosis index (PCI): A widely accepted metric for assessment of disease border in appendix cancer:^[2]

Estimated by contrast enhanced cross sectional imaging.
Both MRI and CT scan has been used and are globally accepted imaging modalities.
Small peritoneal seeding might be difficult to appreciate on CT.
Sometimes it is challenging to distinguish between tumor and mucin.
There are reports in favor of diffusion weighted MRI superiority compared to CT in evaluating extent of peritoneal involvement.^[1]

Table and figure below demonstrate abdominal regions as well as scoring system for PCI.

Major prognostic factors are tumor stage, tumor size, histologic as well genetic characteristics of appendiceal tumors.
TNM classification of tumors of the appendix has been shown in the table below.^[3]


TNM classification of tumors of the appendix ¹
Primary tumor (T)
Tx	Primary tumor cannot be assessed
T0	No evidence of primary tumor
Tis	Carcinoma in situ: intraepithelial or invasion of lamina propria ²
T1	Tumor invades submucosa
T2	Tumour invades muscularis propria
T3	Tumor invades through muscularis propria into subserosa, or into non-peritonealized periappendiceal tissue
T4	Tumor directly invades other organs or structures and/or perforates visceral peritoneum
Regional Lymph Nodes (N)
Nx	Regional lymph nodes cannot be assessed
N0	No regional lymph node metastasis
N1	Metastasis in 1 to 3 regional lymph nodes
N2	Metastasis in 4 or more regional lymph nodes
Distant Metastasis (M)
Mx	Distant metastasis cannot be assessed
M0	No distant metastasis
M1	Distant metastasis
Stage Grouping
Stage 0	Tis N0 M0
Stage I	T1 N0 M0 T2 N0 M0
Stage II	T3 N0 M0 T4 N0 M0
Stage III	Any T N1 M0 Any T N2 M0
Stage IV	Any T Any N M1
¹ The classification applies only to carcinomas. ² This includes cancer cells confined within the glandular basement membrane (intraepithelial) or lamina propria (intramucosal) with no extension through muscularis mucosae into submucosa.