Clinical Etiology of Hypermetabolic Pelvic Lesions in Postoperative Positron Emission Tomography/Computed Tomography for Patients With Rectal and Sigmoid Cancer

Variants and Pitfalls in PET/CT Imaging of Gastrointestinal Cancers

In the past two decades, PET/CT has become an essential modality in oncology increasingly used in the management of gastrointestinal (GI) cancers. Most PET/CT tracers used in clinical practice show some degree of GI uptake. This uptake is quite variable and knowledge of common patterns of biodistribution of various radiotracers is helpful in clinical practice. 18F-Fluoro-Deoxy-Glucose (FDG) is the most commonly used radiotracer and has quite a variable uptake within the bowel. 68Ga-Prostate specific membrane antigen (PSMA) shows intense uptake within the proximal small bowel loops. 11C-methyl-L-methionine (MET) shows high accumulation within the bowels, which makes it difficult to assess bowel or pelvic diseases. One must also be aware of technical artifacts causing difficulties in interpretations, such as high attenuation oral contrast material within the bowel lumen or misregistration artifact due to patient movements. It is imperative to know the common variants and benign diseases that can mimic malignant pathologies. Intense FDG uptake within the esophagus and stomach may be a normal variant or may be associated with benign conditions such as esophagitis, reflux disease, or gastritis. Metformin can cause diffuse intense uptake throughout the bowel loops. Intense physiologic uptake can also be seen within the anal canal. Segmental bowel uptake can be seen in inflammatory bowel disease, radiation, or medication induced enteritis/colitis or infection. Diagnosis of appendicitis or diverticular disease requires CT correlation, as normal appendix or diverticulum can show intense uptake. Certain malignant pathologies are known to have only low FDG uptake, such as early-stage esophageal adenocarcinoma, mucinous tumors, indolent lymphomas, and multicystic mesotheliomas. Response assessment, particularly in the neoadjuvant setting, can be limited by post-treatment inflammatory changes. Post-operative complications such as abscess or fistula formation can also show intense uptake and may obscure underlying malignant pathology. In the absence of clinical suspicion or rising tumor marker, the role of FDG PET/CT in routine surveillance of patients with GI malignancy is not clear.

Comparative analysis of modified Bacon operation and double stapler operation in the treatment of rectal cancer

OBJECTIVE

To investigate the efficacy of modified Bacon operation and double stapler operation in treating lower rectal cancer.

METHODS

A total of 73 patients with lower rectal cancer admitted to the general surgery department of our hospital from March 2016 to March 2017 were selected for the study. According to different operation methods, the patients were divided into an observation group and a control group. Modified Bacon operation was used in the observation group (39 cases), while double stapler operation was adopted for the control group (34 cases). The intraoperative and postoperative conditions and 3-year survival rates were observed.

RESULTS

The bleeding volume and anal exhaust time in the observation group were better than those in the control group, the difference being statistically significant (P<0.05). No significant difference was found between the two groups in terms of the operation time, abdominal drainage volume, anal extubation time, or the number of lymph node dissection (P>0.05). The anal function of the two groups was evaluated one month and six months after operation respectively, and no significant difference was found between the function of the two groups (P>0.05). There was no significant difference in postoperative complications, local recurrence, and distant metastasis between the two groups (P>0.05). The 3-year survival rate was 89.74% in the observation group and 91.18% in the control group. Our analysis found no significant difference in the cumulative survival rates between the two groups (P>0.05).

CONCLUSION

Modified Bacon operation and double stapler operation are effective treatment for lower rectal cancer, and the survival benefit of patients is obvious. The methods are worthy of clinical promotion.