Integrated PET/CT as a first-line re-staging modality in patients with suspected recurrence of ovarian cancer

Surveillance of patients after initial treatment of ovarian cancer

The surveillance of ovarian cancer patients after initial treatment is a challenging question in clinical practice. Serum CA 125 assay, physical examination, and imaging examinations have been employed with different time schedules for the follow-up of asymptomatic patients. Rising serum CA 125 levels may precede the clinical detection of relapse in 56-94% of cases with a median lead time of 3-5 months. An ongoing randomised phase III European trial is comparing the benefits of early administration of chemotherapy based on serum CA 125 assay alone versus delaying treatment until clinical or radiological detection of recurrent disease. Physical examination, with or without ultrasound, is very useful for the surveillance of these patients, since approximately 25-50% of relapses involve the pelvis. Additional radiological imaging techniques, such as computed tomography (CT) and magnetic resonance imaging (MRI), are usually performed in asymptomatic patients with rising CA 125 levels as well as in patients with suspicious symptoms or signs. Integrated positron emission tomography (PET) and CT scanners (PET/CT) can identify recurrent disease in tissues that appear normal at CT imaging as well as metastatic lesions intimately associated with the bowel wall that are difficult to detect with CT or MRI, so that in most series PET/CT has a higher diagnostic reliability than that of conventional imaging techniques. Moreover, PET/CT can disclose unusual supra-diaphragmatic spreading of the disease and may be very helpful for treatment planning, especially for the selection of patients suitable for secondary surgical cytoreduction. A prospective, randomised trial of therapeutic interventions based on stratification by PET/CT disease status could elucidate the real impact of this diagnostic procedure in the management of patients with recurrent ovarian cancer.

Positron emission tomography/computed tomography introduction in the clinical management of patients with suspected recurrence of ovarian cancer: a cost-effectiveness analysis

Aim of this study was to evaluate the economic impact of the introduction of positron emission tomography/computed tomography (PET/CT) in the early detection of recurrent ovarian cancer through a cost-effectiveness analysis of different diagnostic strategies. Thirty-two consecutive patients with suspected ovarian cancer recurrence, studied by both contrast enhanced abdominal CT and PET/CT, were retrospectively included in the study. Three different diagnostic strategies were evaluated and compared: (1) CT only or baseline strategy; (2) PET/CT for negative CT or strategy A; (3) PET/CT for All or strategy B. For each one, expected costs, avoided surgery and incremental cost-effectiveness ratio (ICER) were calculated to identify the most cost-effective strategy. The number of positive patients increased from baseline strategy (20/32) to strategy A and B (30/32 and 29/32 respectively). Positron emission tomography/computed tomography reoriented physician choice in 31% and 62% of patients (strategies A and B respectively). Strategy A is dominated by strategy B, which is more expensive (2909 euro vs. 2958 euro), but also more effective (3 cases of surgery avoided) and presents an ICER of 226.77 euro per surgery avoided (range: 49.50-433.00 euro). Positron emission tomography/computed tomography introduction in this population is cost-effective and allowed to redirect the clinical management of patients towards more appropriate therapeutic choices.

The role of 18F-FDG PET in assessing therapy response in cancer of the cervix and ovaries

For locally advanced cervical cancer, the current literature supports the use of (18)F-FDG PET for assessing treatment response 3 mo after the completion of concurrent chemoradiation. (18)F-FDG PET can provide reliable long-term prognostic information for these patients and, in the future, may be used to guide additional therapy. Investigational areas include the use of (18)F-FDG PET for monitoring response during radiotherapy and chemotherapy in the metastatic and neoadjuvant settings. For ovarian masses, the performance of (18)F-FDG PET in the detection of borderline tumors is limited, and the presence of physiologic (18)F-FDG uptake in normal ovaries of premenopausal women poses another limitation. Preliminary data suggest that the performance of (18)F-FDG PET and (18)F-FDG PET/CT is superior to that of CT alone in initial staging, but the sensitivity of both in the detection of carcinomatosis is limited. Preliminary data also suggest that (18)F-FDG PET may be promising for early prediction of response to chemotherapy and for prediction of response after the completion of chemotherapy. (18)F-FDG PET and (18)F-FDG PET/CT are most helpful in the evaluation of patients with suspected recurrent ovarian carcinoma, especially when CA-125 levels are rising and CT findings are normal or equivocal. PET and CT are complementary, and PET/CT should be used when available. Preliminary data suggest that the addition of (18)F-FDG PET/CT to the evaluation of these patients changes management in approximately a third and reduces overall treatment costs by accurately identifying patients who will or will not benefit from surgery.

Are Surveillance Procedures of Clinical Benefit for Patients Treated for Ovarian Cancer?: A Retrospective Italian Multicentric Study

The aim of this retrospective investigation was to assess the pattern of failures of 412 patients with recurrent ovarian cancer followed up with different surveillance protocols.

Time to recurrence was less than 6 months in 98 women (23.8%), 6 to 12 months in 102 women (24.7%), and more than 12 months in 212 women (51.5%). Symptoms at relapse were referred by 81 women (19.7%). Among the 331 asymptomatic patients, the surveillance procedure that raised the suspect of recurrent disease was clinical examination in 49 (14.8%), imaging technique in 90 (27.2%), serum CA 125 in 77 (23.3%), and both serum CA 125 and imaging technique in 115 (34.7%). At univariate analysis, survival from initial diagnosis was related to stage (P = 0.004), residual disease after initial surgery (P < 0.0001), time to recurrence (P < 0.0001), site of relapse (P = 0.04), and treatment at recurrence (P < 0.0001), and survival after recurrence was related to stage (P = 0.01), residual disease (P < 0.0001), time to recurrence (P < 0.0001), and treatment at recurrence (P < 0.0001). Conversely, symptoms at recurrence had no prognostic relevance. Cox proportional hazards model showed that residual disease and time to recurrence were the only independent prognostic variables for both survival from initial diagnosis (P < 0.0001) and survival after recurrence (P < 0.0001). In conclusion, there was no survival difference between asymptomatic and symptomatic patients at the time of relapse, and therefore, the diagnostic anticipation allowed by a scheduled follow-up protocol did not seem to improve the clinical outcome of patients who ultimately developed recurrent disease.

18F-FDG PET/CT evaluation of patients with ovarian carcinoma

PURPOSE

The role of F-FDG PET has been studied in ovarian carcinoma, but its sensitivity and specificity calculations are based on dedicated PET acquisition, not PET/CT in the majority of the published studies. Therefore, we were prompted to review our experience with PET/CT in the management of patients with ovarian carcinoma.

MATERIALS AND METHODS

This is a retrospective study of 43 women with ovarian carcinoma, 27-80 years old (average: 53.9+/-7.8), who had whole-body PET/CT at our institution from 1 January 2003 to 31 August 2006. We reviewed the patients' outcomes from medical records and compared them to the interpretation of the PET/CT scans. Sensitivity and specificity were calculated using a 2 x 2 table with pathology results (79.1% of the patients) or clinical follow-up (20.9% of the cases) as the 'gold standard'. Confidence interval (CI) estimations were performed using the Wilson score method.

RESULTS

All patients had advanced stage ovarian cancer and the study was requested for re-staging. A total of 60 scans were performed: 30 patients had one scan, nine patients had two scans and four patients had three scans. The administered doses of F-FDG ranged from 381.1 to 769.6 MBq (average: 569.8+/-73.3). PET/CT had a sensitivity of 88.4% (95% CI: 75.1-95.4) and a specificity of 88.2% (95% CI: 64.4-97.9) for detection of ovarian cancer. The SUV max of the detected lesions ranged from 3 to 27 (average: 9.4+/-5.9). The CA-125 tumor marker ranged from 3 to 935 kU/ml (average: 265.2) in patients with positive scans and 4-139 kU/ml (average: 17.1) in patients with negative scans. This difference was statistically significant (P value: 0.0242).

CONCLUSION

This study confirms the good results of F-FDG PET/CT for identification of residual/recurrent ovarian cancer, as well as for distant metastases localization. PET/CT should be an integral part in evaluation of patients with high-risk ovarian cancer or rising values of tumor markers (CA-125), prior to selection of the most appropriate therapy.

The impact of PET-CT in suspected recurrent ovarian cancer: A prospective multi-centre study as part of the Australian PET Data Collection Project

OBJECTIVE

To assess the impact of FDG PET-CT on the management of patients with suspected recurrent ovarian cancer and to determine the incremental information provided by PET-CT.

METHODS

This was a prospective, multi-centre, cohort study. Ninety women (mean age 59.9 years; age range 35-85 years) with a previous history of treated epithelial ovarian carcinoma and suspected recurrence based on elevated CA-125, anatomical imaging or clinical symptoms were studied with FDG PET-CT across two States. Referring doctors were asked to specify a management plan pre-PET, if management was altered after PET-CT and, the impact (rated - none, low, medium, high) of PET-CT on patient management. The pre-PET management plan could include radiotherapy, chemotherapy, surgery, and 'other' including observation. Patients were followed at 6 and 12 months and clinical status, evidence of recurrence and progression were recorded.

RESULTS

Patients were referred by 34 individual specialists. At least 168 additional sites of disease in 61 patients (68%), not identified by conventional imaging were identified by PET-CT. In 77% the additional lesions were located below the diaphragm and most were nodal or peritoneal. PET-CT affected management in 60% (49% high, 11% medium impact). Patients where more disease was detected with PET-CT were more likely to progress in the following 12 months.

CONCLUSIONS

For women with previously treated ovarian carcinoma with recurrent disease, PET-CT can: a) alter management in close to 60% of patients, b) detect more sites of disease than abdominal and pelvic CT, c) is superior in the detection of nodal, peritoneal and subcapsular liver disease and d) offers the opportunity for technology replacement in this setting.

Diagnostic accuracy of integrated FDG-PET/contrast-enhanced CT in staging ovarian cancer: comparison with enhanced CT

PURPOSE

The purpose of the study is to evaluate the accuracy of integrated positron emission tomography and computed tomography (PET/CT) with (18)F-fluorodeoxyglucose (FDG) with IV contrast for preoperative staging of ovarian cancer, in comparison with enhanced CT, using surgical and histopathological findings as the reference standard.

MATERIALS AND METHODS

Forty patients with ovarian cancer underwent FDG-PET/contrast-enhanced CT scans for staging before primary debulking surgery. PET/CT and the CT component separately, were interpreted by two experienced radiologists by consensus for each investigation. Status with regard to lesion inside and outside the pelvis was determined on the basis of histopathology. The significance of differences between the two imaging modalities was determined using the McNemar test.

RESULTS

Staging revealed stage I in 18 patients (IA, n=9; IB, n=3; IC, n=6), stage II in seven (IIA, n=2; IIB, n=3; IIC, n=2), stage III in 14 (IIIA, n=1; IIIB, n=3; IIIC, n=10), and stage IV in one. The results of CT and PET/CT were concordant with the final pathological staging in 22 out of 40 (55%) and 30 out of 40 (75%) cases, respectively. The overall lesion-based sensitivity improved from 37.6% (32 out of 85) to 69.4% (59 out of 85), specificity from 97.1% (578 out of 595) to 97.5% (580 out of 595), and accuracy from 89.7% (610 out of 680) to 94.0% (639 out of 680) between CT and PET/CT. There were significant differences in sensitivity and accuracy, with p values of 5.6 x 10(-7) and 1.2 x 10(-7), respectively.

CONCLUSION

Integrated FDG-PET/contrast-enhanced CT is a more accurate imaging modality for staging ovarian cancer and useful for selecting appropriate treatment than enhanced CT.

Performance of integrated FDG-PET/contrast-enhanced CT in the diagnosis of recurrent ovarian cancer: comparison with integrated FDG-PET/non-contrast-enhanced CT and enhanced CT

PURPOSE

The aim of this study was to evaluate the accuracy of integrated positron emission tomography and computed tomography (PET/CT) using (18)F-fluorodeoxyglucose with IV contrast for depiction of suspected recurrent ovarian cancer and to assess the impact of PET/contrast-enhanced CT findings on clinical management, compared with PET/non-contrast-enhanced CT and CT component.

METHODS

One hundred thirty-two women previously treated for ovarian cancer underwent PET/CT consisting of non-enhanced and contrast-enhanced CT for suspected recurrence. PET/contrast enhanced CT, PET/non-contrast-enhanced CT, and enhanced CT were interpreted by two experienced radiologists by consensus for each investigation. Lesion status was determined on the basis of histopathology, radiological imaging, and clinical follow-up for longer than 6 months.

RESULTS

Patient-based analysis showed that the sensitivity, specificity, and accuracy of PET/contrast-enhanced CT were 78.8% (52 of 66), 90.9% (60 of 66), and 84.8% (112 of 132), respectively, whereas those of PET/non-contrast-enhanced CT were 74.2% (49 of 66), 90.9% (60 of 66), and 82.6% (109 of 132), respectively, and those of enhanced CT were 60.6% (40 of 66), 84.8% (56 of 66), and 72.7% (96 of 132), respectively. Sensitivity, specificity, and accuracy differed significantly among the three modalities (Cochran Q test: p = 0.0001, p = 0.018, and p < 0.0001, respectively). The findings of PET/contrast-enhanced CT resulted in a change of management for 51 of the 132 patients (39%) and had an effect on patient management in 16 patients (12%) diagnosed by enhanced CT alone and three patients (2%) diagnosed by PET/non-contrast-enhanced CT.

CONCLUSION

Integrated PET/contrast-enhanced CT is an accurate modality for assessing ovarian cancer recurrence and led to changes in the subsequent appropriate therapy.