What is the best investigation for a male patient with a history of right hemicolectomy for Colonic cancer (T1a, N0, M0) presenting with right lower quadrant pain, weight loss, and constipation?

From the Guidelines

The best investigation for a male patient with a history of right hemicolectomy for early-stage colon cancer (T1a, N0, M0) who presents with right lower quadrant pain, weight loss, and constipation is a CT scan of the abdomen and pelvis with contrast, as recommended by the most recent guidelines 1. This imaging modality should be performed promptly as these symptoms raise concern for cancer recurrence at the anastomotic site or regional lymph nodes. The CT scan provides detailed visualization of the abdomen, allowing assessment of the surgical anastomosis, potential masses, lymphadenopathy, and other complications like bowel obstruction. Additionally, colonoscopy should follow to directly visualize the anastomosis and remaining colon, with biopsies of any suspicious areas. Laboratory tests including complete blood count, comprehensive metabolic panel, and carcinoembryonic antigen (CEA) levels should be obtained, as elevated CEA may indicate recurrence. These investigations are particularly important given the constellation of concerning symptoms in a patient with previous colon cancer, even though the original cancer was early stage with favorable features. The right lower quadrant pain could represent recurrence at the anastomotic site, while weight loss and constipation further increase suspicion for recurrent malignancy or a developing bowel obstruction. It is also worth noting that PET-CT scan is not routinely recommended for surveillance 1, and its use should be limited to cases with high clinical suspicion of recurrence and negative routine imaging results. The recent guidelines from the Chinese Society of Clinical Oncology (CSCO) also support the use of CT scans and colonoscopy for follow-up in patients with a history of colon cancer 1. In terms of specific follow-up strategies, the CSCO guidelines recommend a follow-up frequency of every 6 months for 5 years for stage I patients, and every 3 months for 3 years, then every 6 months until 5 years postoperatively, and annually after 5 years for stages II-III patients 1. Overall, a CT scan of the abdomen and pelvis with contrast is the best initial investigation for this patient, given its ability to provide detailed visualization of the abdomen and detect potential recurrence or complications.

From the Research

Best Investigation for Colonic Cancer Patient

The patient has a history of right hemicolectomy for Colonic cancer (T1a, N0, M0) and is now presenting with right lower quadrant pain, weight loss, and constipation. The best investigation for this patient would be:

• Abdominal CECT (Contrast-Enhanced Computed Tomography) or
• PET (Positron Emission Tomography) CT, as they are commonly used in the oncology setting and can help in detecting malignant disease 2.
• However, considering the patient's symptoms and history, Abdominal CECT would be a more appropriate initial investigation to evaluate the cause of right lower quadrant pain and constipation.

Alternative Investigations

Other investigations that can be considered are:

• Colonoscopy: to rule out any recurrence or new primary tumor in the colon
• US (Ultrasonography): to evaluate the liver and other abdominal organs for any metastasis
• MRI (Magnetic Resonance Imaging): to evaluate the liver and other abdominal organs for any metastasis, especially if the patient has a contraindication to CT scan.

Diagnostic Performance of Imaging Modalities

The diagnostic performance of different imaging modalities for detecting colorectal cancer liver metastases has been evaluated in a study, which found that:

• MRI had the highest sensitivity on a per-lesion basis, with a sensitivity of 89% 3.
• CEUS (Contrast-Enhanced Ultrasound) and MDCT (Multidetector Computed Tomography) had comparable sensitivities, with a sensitivity of 86% and 84%, respectively 3.
• PET CT had a sensitivity of 62% on a per-lesion basis, but had a high sensitivity on a per-patient basis, with a sensitivity of 96% 3.

Use of Contrast-Enhanced CT

The use of contrast-enhanced CT has been evaluated in several studies, which found that:

• Contrast-enhanced CT is useful in characterizing hypervascular liver metastases and incidental findings 4.
• The addition of non-contrast CT to contrast-enhanced CT did not significantly improve the characterization of hypervascular liver metastases, but improved the confidence level of radiologists 4.
• Contrast-enhanced CT is appropriate in certain clinical scenarios, such as suspected malignant disease, and the choice of contrast agent depends on the route of administration, desired tissue differentiation, and suspected diagnosis 5.