Diagnosis

Diagnosis of peritoneal carcinomatosis is based on radiological techniques and surgical evaluation. Determining the severity of the carcinomatosis is a fundamental requirement to establish adequate treatment.  

Computerised axial tomography (CAT), magnetic resonance imaging (MRI) and positron emission tomography (PET) are the preoperative tests for the diagnosis of carcinomatosis. Sometimes, more invasive tests such as biopsies are required.  

Descriptions of these diagnostic tests for the disease are given below:  

•    Computerised axial tomography can detect lesions of 5 mm or more and has a sensitivity (ability to detect images that are actually pathological) of 70% in lesions of 2 cm. It can also detect indirect signs of peritoneal disease, such as a build-up of fluid in the abdomen.  

•    Magnetic resonance imaging has higher sensitivity for detecting nodules of all sizes. It can reach 85-90% in lesions smaller than 1 cm.  

•    Positron emission tomography detects faster metabolism of tumour cells. Its sensitivity is 58-100%. Some tumours, such as mucinous tumours, are not detectable (false negatives), and some inflammatory lesions can mimic the behaviour of tumour cells (false positives).

•    Surgical examination is the only method with a sensitivity approaching 100% of detecting peritoneal carcinomatosis. Tissue and liquid samples can be taken for subsequent laboratory diagnosis. The method used most is laparoscopic surgery.  

Classification according to the extent of peritoneal disease is important for both treatment and prognosis of the disease.  

The most accurate classification to date is based on quantifying the volume of carcinomatosis according to the size of the tumours and their location in the abdominal cavity. A scale from 0 to 39 is used.  

In some cases, the cause of the carcinomatosis is diagnosed during surgery, which may change the initially outlined therapeutic plan.  

Metastasis in other organs is common in patients with carcinomatosis. Various parameters, such as the patient’s nutritional status, test results or response to chemotherapy need to be assessed for an exact diagnosis. A multidisciplinary team, therefore, is required for the proper diagnosis of PC.