Elsevier

Gynecologic Oncology

Volume 108, Issue 1, January 2008, Pages 160-165
Gynecologic Oncology

Impact of FDG PET-CT imaging on the decision making in the biologic suspicion of ovarian carcinoma recurrence

https://doi.org/10.1016/j.ygyno.2007.07.082Get rights and content

Abstract

Objectives.

The aim of this prospective study was to evaluate the impact of integrated PET-CT on treatment management in ovarian carcinoma recurrence suspicion because of increased CA-125.

Methods.

Twenty-nine patients (mean age = 61 years), initially treated for ovarian carcinoma (FIGO stage I n = 2, stage II n = 3, stage III n = 21 and stage IV n = 3), presenting with increased CA-125 (mean = 160 IU/ml, range 33–1930), underwent subsequently a CT and a PET-CT scans. The recurrence was acknowledged by the referring physicians for all patients. The impact of PET-CT on patient’s management was evaluated by comparing the therapeutic decision mentioned respectively on the pre and post PET-CT questionnaires filled in by the oncologists.

Results.

The CT scan was positive in 22/29 patients (76%) and negative in 7/29 patients (24%). The PET-CT scan was positive in 27/29 patients (93%) and negative in 2/29 (7%) patients. Five out of the seven patients with a negative CT scan had a positive PET-CT scan. In comparison to CT scan alone, the PET-CT scan modified the disease distribution for 16 patients (55%; p < 0.001) in the following ways: more advanced disease (n = 11), more limited disease (n = 4), and different localizations (n = 1). The assessment of pre and post PET-CT questionnaires showed a statistically significant change in the decision making for 10 patients (34%, p < 0.0001).

Conclusion.

This questionnaire-based study showed that PET-CT imaging allows a better restaging than CT and induces a change in clinical management in over one third of patients with suspected ovarian carcinoma recurrence on increased CA-125.

Introduction

Ovarian carcinoma is one of the most common gynecologic malignancies and has a poor prognosis. Most of the time, the diagnosis is made at an advanced stage. Recurrence is frequent, especially in the 2 years following the first-line therapy. Monitoring of the serum tumor marker CA-125 is the reference method for the detection of ovarian carcinoma recurrences with a positive predictive value close to 100%, when there is an increased CA-125 on several measures [1], [2], [3]. However, it does not allow to localize the recurrence nor to differentiate between localized and diffuse disease. Because CA-125 is essentially expressed by serous ovarian carcinoma, it has limited value in the follow-up of the other histologic forms. CA-125 has a relatively low specificity and can be increased in case of inflammation of serous tissues, endometriosis and non-ovarian carcinoma such as hepatic or pancreatic carcinoma.

Despite recent progress in diagnostic imaging, especially MR imaging and helical CT with contrast enhancement, detection of the sites of recurrence using these conventional imaging modalities can be difficult, in particular in the small peritoneal lesions and in case of peritoneal abnormalities due to post-surgical modifications [4], [5]. (18F)-fluoro-d-deoxyglucose positron emission tomography (FDG PET) has demonstrated its usefulness in the early detection of the site of recurrence with an accuracy range from 79% to 96% [6], [7], [8], [9], [10], [11], [12]. Integrated PET-CT has shown to be more sensitive than either technique alone by combining metabolic and anatomic information [7], [13], [14], [15]. However, its impact on the patient management has not yet been assessed. We therefore conducted a questionnaire-based prospective study to evaluate the impact of integrated PET-CT on the decision making in suspicion of ovarian carcinoma recurrence because of an increased CA-125.

Section snippets

Patients characteristics

From October 2004 to November 2006, 29 patients (mean age = 61 years, range 44–80), presenting with a suspected ovarian carcinoma recurrence because of increased CA-125 (mean = 160 IU/ml, median = 75 IU/ml, range 33–1930, Standard Deviation (SD) = 351), were included in this prospective study. The patients were referred by oncologists who had agreed to participate to our questionnaire-based study (see below). The rising of CA-125 was confirmed on at least 2 measures. The characteristics of patients and

Comparison of CT and PET-CT results

The CT scan was positive in 22/29 patients (76%) and negative in 7/29 patients (24%). The PET-CT scan was positive in 27/29 patients (93%) and negative in 2/29 (7%) patients. Table 2 details the distribution of lesions on the CT and PET-CT scans. In 5 patients with negative CT scan but positive PET-CT scan, the FDG PET findings were localized in the peritoneum: perihepatic and perisplenic areas (n = 1); pelvis (n = 1); diffuse carcinomatosis (n = 1, Fig. 1); lymph node abnormalities were also found

PET-CT results

With an accuracy range from 79% to 96% (6–12), PET-CT imaging improves the overall sensitivity and specificity of ovarian tumor recurrence detection, as compared to CT scan and PET scan alone [9], [13], [17].

In our study, the sensitivity of PET-CT imaging was higher than that of CT with 27/29 positive PET-CT scans (93%) compared to 22 positive CT scans (76%), as shown in Table 2. Our results are in agreement with the results of Simcock et al. [18], for whom PET-CT scan was positive in all but

Conclusion

In our prospective study, which evaluated the impact of FDG PET-CT imaging on the decision making, a change of the therapeutic strategy was obtained in approximately one third of patients presenting with a suspected ovarian carcinoma recurrence because of increased CA-125. PET-CT imaging allows a better restaging than CT imaging alone, and the impact on the decision making is particularly obvious in patients with negative CT scan because detection of the recurrence sites may lead to administer

Acknowledgments

This study was supported by the Comité départemental de la Ligue Contre le Cancer des Hauts de Seine.

We would like to thank Pr Francois Goldwasser, Dr Gérard Auclerc, Dr Yves Otmezguine, and Dr Paul-Henri Cottu for their contribution to this study.

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