The usefulness of a repeat study for differentiating between bowel activity and local tumor recurrence on FDG PET scans

The value of using fludeoxyglucose positron-emission tomography scan with respect to colorectal abnormalities-a cross-sectional study

Background

Fludeoxyglucose positron-emission tomography (FDG-PET) shows colic uptake regularly. Complementary colonoscopy is done. Aim: study the findings of colonoscopy.

Methods

All consecutive scans in 5 years were studied. Focal FDG uptake in colon and/or rectum were scored as + or ++. Clinical files and endoscopy reports were studied for final diagnosis.

Results

Focal FDG uptake was noted in 173 out of 2,075 scans (8.4%). Focal FDG activity was judged ++ in 73 patients (42.2%) and + in 100 (57.8%). The majority of colorectal cancers scored ++. Patients with ++ activity underwent or had undergone significantly more often a colonoscopy compared with patients with + activity, 82% versus 65% (P=0.02). FDG PET/CT was false positive with respect to polyp(s) or cancer in 13 cases (22%) of ++ FGD activity and in 38 cases of + FDG (P<0.001). In 25 patients a total of 69 polyps were not FDG avid.

Conclusions

FDG-PET scanning is a useful tool in oncology. However, false-positive and false-negative findings with respect to colonic uptake are present in a significant number of patients. If the clinical condition and the potential prognosis allows the performance of colonoscopy this procedure should be done.

Dual-time-point F-18 FDG PET/CT imaging for differentiating the lymph nodes between malignant lymphoma and benign lesions

Purpose

The purpose of the present study is to evaluate the clinical value of dual-time-point F-18 FDG PET/CT imaging to differentiate malignant lymphoma (ML) from benign lymph node (BLN).

Materials and methods

The subjects were 310 lymph nodes in 84 patients (195 ML lesions in 30 patients and 115 BLN in 54 patients associated with various etiologies.). F-18 FDG PET/CT scan was performed at 50 min (early scan) and at 100 min (delayed scan) after the injection. First, the maximum standardized uptake value (SUVmax) of each lesion at early and delayed scans was calculated. Second, we estimated the difference between early and delayed SUVmax (D-SUVmax) and the retention index (RI-SUVmax) to evaluate the change of tracers in the lesions. Furthermore, proper cut-off values of them were evaluated using receiver operating characteristic analysis. The efficacy of each parameter was analyzed with ANOVA.

Results

Delayed SUVmax and D-SUVmax in ML were significantly higher than those in BLN. Proper cut-off value in delayed SUVmax was 4.0 and in D-SUVmax was 1.0. When the proper cut-off value in D-SUVmax was applied, the D-SUVmax yielded the role of diagnosis with sensitivity of 82.6 %, specificity of 65.2 %, positive predictive value of 80.1 % and negative predictive value of 68.8 %, respectively.

Conclusions

The delayed SUVmax and D-SUVmax were useful indices to differentiate ML from BLN, regardless of histologic subtype. Dual-time-point F-18 FDG PET/CT imaging may help to consider whether there is any need to proceed to more invasive tests, such as biopsy, in individual patients.

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Emergency surgery for recurrent intraabdominal cancer

Background

Recurrent abdominal cancer can manifest in many ways but there are certain situations that are a great challenge to clinicians. Emergency presentation is one such situation. Surgeons are faced with a therapeutic dilemma that on the one hand most of these patients have a limited life expectancy, and on the other surgical procedures are unavoidable. We reviewed our experience of recurrent abdominal cancers presenting with acute abdominal symptoms requiring emergency.

Patients and methods

Over the last 10 years, 81 patients with recurrent abdominal cancer presented with an abdominal emergency. Case records, operative notes and histology were reviewed. Frequency distributions were prepared for clinical, hematological, biochemical parameters, treatment and complications. Surgical analysis was carried out by the Kaplan Meier method and groups were compared using a log-rank test.

Results

The mean age of the patients was 70.1 years with a female to male ratio of 1.25. An overall postoperative mortality of 11.1% and morbidity of 27.1% was observed. Postoperative infections and respiratory complications were the most common causes of morbidity and mortality. Emergency resections carried the same risk of mortality and morbidity as the other surgical procedures (p > 0.05). Patients who underwent radical or palliative resections had a better survival than patients undergoing other procedures (p < 0.05). Preoperative Apache II score was found to be single most important predictor of postoperative mortality and morbidity.

Conclusions

We conclude that surgical resection offers the best chance for improvement in survival after emergency surgery for recurrent abdominal cancer. If resection is not feasible, the possibility of creating a bypass or enterostomies should be considered to improve the patients' quality of life.