Positron Emission Tomography /Computed Tomography Follow-Up in Patients with Gastrointestinal Tract Malignancies

Background: PET/CT has an increasing role in the oncology field, including GIT. The role of PET/CT is more significant in the follow-up than initial staging and diagnosis as it helps in therapy assessment and detects recurrence and metastasis. In esophageal cancer, it helps by detecting the distant metastasis and discover synchronous neoplasm. Also, it is acclaimed to help in early detection of the response of the patient to chemo and radiotherapy. In the follow-up, it may be useful to detect recurrence. PET/CT has a minimal role in gastric cancer, as it shows no superiority over C.T. alone. For Colorectal Cancer, PET/CT has a good value in cases of suspected liver or lung metastasis and local recurrence after surgery. This study aimed to evaluate the impact of PET/CT on treatment decision & follow-up of patients with gastrointestinal tract malignancies.

Methods: This study is a cross-sectional study and was done retrospectively by collecting data and records of 47 GIT malignancy patients who underwent PET/CT during or after treatment. At PET/CT unit, Diagnostic Radiology Department in Educational hospitals - Tanta University between July 2015 and December 2017.

Results: The patients were mainly colorectal in the site and primarily adenocarcinoma in type. We found that 27.7% of cases treatment plans were influenced by the PET/CT results, the percentage is highest with colon cancer (40%) then rectal cancer (25%), and our few esophageal, gastric, intestinal malignancies cases have shown no influence which is due to a small number of cases. PET/CT seems to have the best add value in patients with colorectal cancer with metastasis with a 66.7% change in treatment plans. Six patients had inconclusive results of PET/CT due to scan limitations.

Conclusion: Relying on PET/CT in clinical decisions in esophageal or gastric cancer is not encouraged unless in case of clinical or imaging suspicion of recurrence. On the other hand, PET/CT is useful in detecting post-treatment metastasis and local recurrence in colorectal cancer.