A 62-year-old man underwent an extended right hemicolectomy for an obstructed right transverse colon carcinoma, and was discovered intraoperatively to have a tumor deposit in the omentum, which was also resected. Postoperatively, he received six cycles of FOLFOX. One year after surgery, surveillance PET/CT reveals an isolated solitary 2.5-cm metastasis in the right liver, which was considered amenable to immediate surgery. During resection of the liver lesion, additional disease was found in the adjacent parietal peritoneum. Upon recovery from surgery, he will undergo further systemic therapy.
Case Discussion:
DR PRIMROSE: This was a 62-year old man who underwent an extended right hemicolectomy for an obstructed transverse colon carcinoma and now presented with omentum metastases, a sign of peritoneal dissemination and a solitary metastasis in the right liver. Although the PET scan suggested no other disease was present, it was discovered intraoperatively that the patient had a solitary metastasis and the parietal peritoneum adjacent to the metastasis had additional disease, according to the results of subsequent histology. So some peritoneal disease was found around the metastasis. This was a bad prognostic feature, because if you have disease in the peritoneum, it is normally incurable.
The recovery after chemotherapy was unremarkable. Because his prognosis was unfavorable, he will probably receive a FOLFIRI-type schedule used, because the patient has already received six months of FOLFOX as adjuvant treatment. Because the patient had an omentum deposit, it was assumed that the patient had disseminated disease, and so he was being managed in that light, not with a plan to resect. So the six months of FOLFOX was administered was to treat advanced disease.
For all patients, we conduct multislice CT of the chest, abdomen and pelvis, and MRI scans are performed on all patients who will undergo liver resection. In our practice, we do not use PET scanning on everyone — we use PET scans for patients who are likely, on the basis of the presentation, to have extrahepatic disease. So that is really the value of the PET imaging. It’s unusual for a PET scan to provide much information about the liver, unless there is some equivocation from the liver-dedicated CT as to whether a lesion is malignant or not. In that situation, it sometimes helps, but normally a PET scan is used to evaluate the patient for potential extrahepatic disease. The CT and the MRI provide more information on the liver than the PET/CT. The other problem we have with PET/CT is false-positives and false-negatives, and particularly we’ve found patients with inflammatory fossae in the pelvis that are called malignant by the report, and turn out to be benign. So, if we find something unexpected on a PET scan, we always follow up with some further imaging and probably a biopsy, to ensure that it wasn’t a false-positive. Otherwise, you may be denying a patient an operation that could be beneficial on the basis of our investigation. I believe that PET/CT perhaps isn’t used as much in the United Kingdom liver centers as in the United States, where I think it’s more commonly used.
