ORIGINAL ARTICLE
Carcinoma Endometrium Role of 18-FDG PET/CT for Detection of Suspected Recurrence Punit Sharma, MD,* Rakesh Kumar, MD, PhD,* Harmandeep Singh, MD,* Sunil Jeph, MD,* Daya Nand Sharma, MD,Þ Chandrasekhar Bal, MD,* and Arun Malhotra, PhD* Objective: Recurrent carcinoma endometrium has a poor prognosis. However, successful salvage with long-term survival has been achieved after hormone therapy, radical surgery, and radiotherapy/chemotherapy in patients with recurrent disease. Conventional imaging (CI) and tumor marker have limited accuracy for detecting recurrence in these patients. The aim of the present study was to evaluate the role of 18-flurodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) in patients suspected to have recurrence of carcinoma endometrium. Methods: In this retrospective study, total 101 patients were evaluated. All patients had undergone surgery with/without adjuvant therapy (chemotherapy/ radiotherapy/both) for histologically proven carcinoma endometrium. They underwent 18-FDG PET/CT studies for suspected recurrence. Comparable CI (contrast-enhanced CT and/or magnetic resonance imaging) was available for 76 patients. Results of FDG PET/CT were confirmed with clinical/imaging follow-up and/or histopathology. Results: The mean age was 56.9 T 8.6 years. 18-FDG PET/CT was positive for recurrence in 51 (50.5%) patients and negative in 50 (49.5%). Locoregional disease was observed in 24 patients, metastatic disease was observed in 10, and 17 showed both locoregional and metastatic disease. The sensitivity, specificity, positive and negative predictive values, and accuracy of 18-FDG PET/CT were 88.9%, 93.6%, 94.1%, 88%, and 91%, respectively. 18-FDG PET/CT showed strong positive correlation with final diagnosis based on reference standard (J 0.823; P = 0.0001). Compared to CI, 18-FDG PET/CT has much higher specificity (62% vs. 96.4%), and accuracy (76.3% vs. 92.1%), with comparable sensitivity (85.1% vs. 89.5%). Conclusion: 18-FDG PET/CT is a highly sensitive and specific modality for detecting recurrence in post-therapy patients of carcinoma endometrium with suspected recurrence. It performs better than CI. Key Words: carcinoma endometrium, recurrence, FDG, PET/CT (Clin Nucl Med 2012;37: 649Y655)
C
arcinoma endometrium is a common gynecological cancer with an overall favorable prognosis. Because most of the patients have early-stage disease at the time of diagnosis, the survival rate of patients with carcinoma endometrium is expected to be high.1,2 However, in advanced or recurrent endometrial carcinoma, the prognosis is poor.1,3,4 The only exception being patients with isolated vaginal recurrence who continue to have a favorable prognosis.3 Patients with localized recurrences are classically treated by cytoreductive surgery with or without radiation, whereas those with disseminated recurrent disease are candidates for hormonal therapy or systemic taxol-based chemotherapy regimens.5,6 In spite of the poor prognosis, successful
Received for publication February 26, 2011; revision accepted April 10, 2011. From the Departments of *Nuclear Medicine and †Radiation Oncology, All India Institute of Medical Sciences, New Delhi, India. Conflicts of interest and sources of funding: none declared. Reprints: Rakesh Kumar, MD, PhD, E-81, Ansari Nagar (East), AIIMS Campus, New Delhi 110029, India. E-mail:
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salvage with long-term survival has been achieved after hormone therapy, radical surgery, and radiotherapy/chemotherapy in patients with recurrent disease.5,7Y9 This provides an important rationale for the introduction of an effective diagnostic modality in the management of women who are suspected to have recurrence of carcinoma endometrium. Conventional surveillance of carcinoma endometrium patients consists of a physical examination, evaluation of serum tumor markers, and imaging studies. However, these methods are not very accurate and do not exactly identify sites of recurrence. Post-treatment serum levels of tumor markers like CA125 and, to a lesser extent, CA19.9 have been shown to be useful indicators of active recurrences. However, these tumor markers are unable to localize the site of disease.10,11 Imaging studies, such as contrast-enhanced computed tomography (CECT) and magnetic resonance imaging (MRI), are routinely used to evaluate disease extension and provide important information for treatment planning.8,12 Despite the widespread use of these conventional imaging (CI) modalities, accuracy for the detection of tumor recurrence has been low.10,13 The accuracy of anatomic imaging techniques, such as CECT or MRI, for the diagnosis of recurrences is limited by the presence of postsurgical or postradiation changes. Under these circumstances, tissue sampling may be required to differentiate treatment-related scarring or fibrosis from recurrent disease with certainty.6,8,10,13 Metabolic imaging by positron emission tomography (PET) with 18-fluorodeoxyglucose (18-FDG) is now widely used in oncology. Integrated PET/CT offers the combined benefits of anatomic and functional imaging; it has been used to localize areas of increased FDG uptake, with improved anatomic specificity.10,14 Integrated PET/ CT is now widely used for evaluation of suspected recurrence in patients with cervical and ovarian carcinoma.15,16 However, limited information is available regarding the usefulness of 18-FDG PET/CT in recurrent carcinoma endometrium.17Y21 Moreover, either these studies have used 18-FDG PET alone17,22Y24 or a mixed population of cervical and endometrial cancers, with limited numbers of patients.18,21,25 A study evaluating the role of integrated 18-FDG PET/CT in a larger patient population with suspected recurrence of endometrial carcinoma is lacking. Therefore, the purpose of the present retrospective study was to evaluate the accuracy of integrated 18-FDG PET/CT for the identification of suspected recurrent carcinoma endometrium after treatment and comparison with CI if available.
MATERIALS AND METHODS Patients The study was conducted after taking approval from the Institutional Review Board. In all, 101 patients, with suspected recurrent endometrial carcinoma who underwent 18-FDG PET/CT study between September 2006 and May 2010, were reviewed for this retrospective study. All the patients had histologically proven endometrial carcinoma and had undergone surgery with or without adjuvant therapy (radiotherapy/chemotherapy/both). All the patients had suspected recurrence based on clinical symptoms, raised tumor markers (CA125 Q35 U/mL), and findings of other imaging modalities. Those www.nuclearmed.com
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patients who had received chemotherapy in G3 weeks and surgery and radiotherapy in G6 weeks were excluded.
18-FDG PET/CT Acquisition The scans were done with a dedicated PET/CT scanner (Biograph 2, Siemens, Erlangen, Germany). All patients fasted for at least 4 hours. Blood glucose was G140 mg/dL. A dose of 370 MBq (10 mCi) of 18-FDG was injected intravenously. The patients rested in a quiet room and after a 45- to 60-minute uptake period, were taken for PET/CT scan. No intravenous contrast agent was administered for the CT part of PET/CT. Oral contrast media was administered as routinely done for opacification of bowel. In the PET/CT system, CT acquisition was performed on spiral dual-slice CT, with a slice thickness of 4 mm and a pitch of 1. Image was acquired using a matrix of 512 512 pixels and pixel size of 1 mm. After CT, 3 dimensional PET acquisition was done for 2 to 3 minutes per bed position. PET data were acquired using matrix of 128 128 pixels, with a slice thickness of 1.5 mm. CT-based attenuation correction of the emission images was used. PET images were reconstructed by iterative method, ordered subset expectation maximization (2 iterations and 8 subsets). After CT acquisition, PET acquisition of the same axial range was started with the patient in the same position on table. After completion of PET acquisition, the reconstructed attenuation-corrected PET images, CT images, and fused images of matching pairs of PET and CT images were available for review in axial, coronal, and sagittal planes, as well as in maximum intensity projections, 3 dimensional cine mode.
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Reference Standard A combination of clinical follow-up/imaging follow-up (CECT/ MRI/ultrasonography [USG]/PET/CT) (minimum 6 months; range: 6Y28 months after 18-FDG PET/CT) and/or histopathology (when available) was taken as reference standard. Because histopathological confirmation of all lesions was not ethically and technically feasible, histopathology was available only for 23 studies. Lesions showing increase in size on radiologic follow-up and/or increase in FDG uptake on follow-up PET/CT were taken as true positive. Similarly, lesions showing response to anticancer therapy were taken as true positive. Lesions not showing any change/decrease in size/FDG uptake on follow-up without any therapy were taken as false-positive. Results of the 18-FDG PET/CT were also compared with CI when done within an interval of G4 weeks.
Statistical Analysis Sensitivity, specificity, accuracy, and positive (PPV) and negative predictive value (NPV) of 18-FDG PET/CT and CI (when available) were calculated with 95% confidence interval. McNemar test was used to compare the diagnostic abilities of CI and 18-FDG PET/ CT. The P value G0.05 was considered as significant. The agreement of PET/CT with the final diagnosis was also determined by means of the Cohen’s kappa coefficient (J). All the data analyses were TABLE 2. Performance of PET/CT in Detecting Recurrence (Results With 95% Confidence Interval) 18-FDG PET/CT
Image Interpretation 18-FDG PET/CT study was evaluated by 2 experienced Nuclear Medicine physicians. Both of them were unaware of other clinical or imaging information at the time of review, and independently interpreted the 18-FDG PET images. In cases of disagreement, a final decision was made by consensus. Any area of increased 18-FDG uptake was looked for keeping the physiological tracer distribution in perspective. Positive findings on 18-FDG PETwere localized to anatomic images from the nonenhanced CT. The 18-FDG PET/CT findings were grouped as locoregional disease and metastatic disease.
Parameters Recurrence No recurrence Sensitivity Specificity PPV NPV Accuracy
Positive
Negative
48 03
06 44 88.9% (77.3%Y95.7%) 93.6% (82.4%Y98.5%) 94.1% (83.7%Y98.7%) 88.0% (75.6%Y95.4%) 91.0%
18-FDG indicates 18F-flurodeoxyglucose; PET/CT, positron emission tomographycomputed tomography; PPV, positive predictive value; NPV, negative predictive value.
TABLE 1. Patient Characteristics Characteristics Total patients Age (y) Median Range Primary FIGO stage Stage I Stage II Stage III Stage IV Primary histopathology Adenocarcinoma Adenosquamous carcinoma Poorly differentiated carcinoma Treatment Surgery Surgery + chemotherapy Surgery + radiotherapy Surgery + chemotherapy + radiotherapy
Frequency
%
101
V
56 35Y77
V V
63 26 10 02
62.4 25.7 9.9 2.0
91 09 01
90.1 9.0 0.9
46 14 18 23
45.5 13.9 17.9 22.7
Site
FIGO indicates International Federation of Gynecology and Obstetrics.
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TABLE 3. Sites of Recurrence in 18-FDG PET/CT Frequency
Loco regional Local recurrence Regional lymph nodes Distant Lung Liver Bone Adrenal Spleen Peritoneum Abdominal wall Skin Breast Pancreas
17 34 15 04 06 02 02 06 01 01 01 01
More than 1 site of metastasis was observed in many studies. 18-FDG indicates 18F-flurodeoxyglucose; PET/CT, positron emission tomographycomputed tomography.
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PET/CT for Recurrent Carcinoma Endometrium
FIGURE 1. A 44-year-old female patient with stage I (FIGO) adenosquamous carcinoma of endometrium. She underwent total abdominal hysterectomy along with bilateral salpingo-oopherectomy. The patient presented with rising CA125 on follow-up. Transaxial CT (A), 18-FDG PET (B), and 18-FDG PET/CT (C) images of the same patient showing a pelvic soft tissue lesion with intense 18-FDG uptake (arrow). A diagnosis of local recurrence was made, which was confirmed on biopsy. FIGO indicates International Federation of Gynecology and Obstetrics; 18-FDG, 18F-flurodeoxyglucose; PET/CT, positron emission tomography/computed tomography.
performed using the statistical software packages SPSS 11.5 (SPSS Inc., Chicago, IL).
RESULTS Total 101 patients were included in the study. Patient characteristics, including age, primary histopathology, International Federation of Gynecology and Obstetrics (FIGO) stage, and treatment received, are detailed in Table 1. Histologic confirmation was present for 23 patients, while clinical and imaging follow-up was available for re-
maining 78 patients. Based on reference standard mentioned in Methods, recurrent disease was present in 54 patients, whereas there was no recurrent disease in 47 patients.
18-FDG PET/CT Findings Based on the criteria mentioned in Methods, of 101 patients, 51 (50.5%) were positive and 50 (49.5%) were negative for recurrent disease. Result of 18-FDG PET/CT as compared with reference standard is detailed in Table 2. 18-FDG PET/CT showed strong positive
FIGURE 2. A 55-year-old female patient with stage I (FIGO) adenocarcinoma of endometrium. She underwent total abdominal hysterectomy along with bilateral salpingo-oopherectomy. The patient presented with clinical symptoms on follow-up. Transaxial CT (A), 18-FDG PET (B), and 18-FDG PET/CT (C) images of the same patient showing enlarged right external iliac lymph node with increased 18-FDG uptake (arrow). Also noted, a small left internal iliac lymph node showing increased 18-FDG uptake (arrowhead), which was missed on CI. The left internal iliac lymph node increased in size on follow-up CI, confirming metastatic disease. FIGO indicates International Federation of Gynecology and Obstetrics; 18-FDG, 18 F-flurodeoxyglucose; PET/CT, positron emission tomography/computed tomography. * 2012 Lippincott Williams & Wilkins
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FIGURE 3. A 56-year-old female patient with stage I (FIGO) adenocarcinoma of endometrium. She underwent surgery followed by adjuvant radiotherapy. The patient presented with mediastinal mass on follow-up observed on CI. Transaxial CT (A), 18-FDG PET (B), and 18-FDG PET/CT (C), images of the same patient showing left posterior mediastinal mass with increased 18-FDG uptake and central necrosis. Also noted, right lung parenchymal nodule. A diagnosis of metastatic carcinoma to lung was made. FIGO indicates International Federation of Gynecology and Obstetrics; 18-FDG, 18F-flurodeoxyglucose; PET/CT, positron emission tomography/computed tomography.
correlation with the final diagnosis based on reference standard (J 0.823; P = 0.0001). Locoregional disease was observed on PET/CT in 24 patients, metastatic disease was observed in 10 studies, and 17 studies showed both locoregional and metastatic disease. The sites of locoregional disease were local recurrence in 7 patients (Fig. 1), regional lymph nodes in 24 patients (Fig. 2), and both local recurrence and regional lymph nodes in 10 patients. Lung was the most common site of distant metastasis (n = 15) (Fig. 3), followed by bone and peritoneum (n = 6 each). Other sites of metastatic involvement are detailed in Table 3. All of the 3 false-positive studies showed lymph nodal involvement on 18-FDG PET/CT (retroperitoneal in 2; mediastinal in 1). Of these 3 patients, 1 had tubercular lymphadenitis (confirmed with fine needle aspiration cytology [FNAC]; resolved with antitubercular therapy) and other 2 had nonspecific inflammation/infection, which spontaneously resolved on follow-up. Of the 6 false-negative studies, 2 patients had lung metastasis (confirmed with CECT), 2 had local recurrence (follow-up), 1 patient had lymph nodal disease (CECT; FNAC), and 1 patient had bone metastasis to L3 vertebra (bone scan; follow-up 18-FDG PET/CT).
Comparison With Conventional Imaging Comparative CI (CECT, MRI, USG, bone scan) was available for 76 PET-CT studies. CI was done as segmental examination of chest (including lower neck), abdomen, and pelvis. Of these 76 PET/ CT studies, 44 were positive for recurrence and among these, 43 were true positive, whereas 1 was false-positive. Total 32 PET/CT studies were negative for recurrence. Twenty-seven were true negative and 5 were false-negative. Comparison of sensitivity, specificity, PPV, NPV, and accuracy of CI and PET/CT is given in Table 4. CI and PET/CT were concordant in 53 patients (Fig. 4) and discordant in 23 patients. Although McNemar test did not reveal any significant difference between diagnostic accuracies of the 2 modalities (P = 0.210), PET/CT showed a better specificity as compared with CI.
DISCUSSION Carcinoma endometrium is the most common gynecological malignancy in the North America and Europe.26,27 Most patients are diagnosed at early stages, making them curable by surgery with or without adjuvant therapy.1,2 Unfortunately, a significant portion of 652
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patients with risk factors have recurrence, usually within 2 years of initial treatment.1 Traditionally, in such patients, the prognosis is considered to be poor.1,3,4 However, recent studies in patients with recurrent endometrial cancer have yielded reduced mortality and prolonged survival with the use of multimodality treatments.28,29 It is being widely accepted now that early and accurate detection of recurrence in patients with carcinoma endometrium is expected to have a significant impact on overall survival.2 Post-treatment serum levels of tumor markers (CA125, CA19.9), although useful, are unable to localize the site of disease.10,11 CI modalities, such as CECT, MRI, and USG, are commonly used for detection of recurrence in these patients. However, it is difficult for these imaging modalities to correctly differentiate between tumor recurrence and postsurgical or postradiotherapy changes.13 These limitations provide an important rationale for the assessment of the potential value of metabolic imaging in such patients. Like other gynecological malignancies, carcinoma endometrium also shows increased rates of glycolysis30 and 18-FDG uptake.31 Ryu et al evaluated the role of PET alone in 127 asymptomatic posttherapy patients of carcinoma endometrium.17 The sensitivity of PET was 100% and specificity was 88% for detecting recurrent disease. Saga et al in their study found PET to be highly sensitive (100%) and specific (88.2%) for detecting recurrence.23 In spite of these promising results, 18-FDG PET proved to have limitations due to its spatial resolution and poor anatomic localization. Integrated PET/CT
TABLE 4. Comparative Representation of Diagnostic Ability of CI and PET/CT Parameter
Conventional Imaging (95% Confidence Interval)
18-FDG PET/CT (95% Confidence Interval)
Sensitivity Specificity PPV NPV Accuracy
85.1% (71.6%Y93.7%) 62% (42.2%Y79.2%) 78.4% (64.6%Y88.7%) 72% (50.6%Y87.8%) 76.3%
89.5% (77.3%Y96.4%) 96.4% (81.5%Y99.4%) 97.7% (87.9%Y99.6%) 84.3% (67.2%Y94.6%) 92.1%
18-FDG indicates 18F-flurodeoxyglucose; PET/CT, positron emission tomographycomputed tomography; PPV, positive predictive value; NPV, negative predictive value.
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PET/CT for Recurrent Carcinoma Endometrium
FIGURE 4. A 55-year-old female patient with stage II (FIGO) adenocarcinoma of endometrium. She underwent total abdominal hysterectomy along with bilateral salpingo-oopherectomy. The patient presented with rising CA125 on follow-up. Transaxial CT (A), 18-FDG PET (B), and 18-FDG PET/CT (C), images of the same patient show enlarged aortocaval lymph node with increased 18-FDG uptake. The patient also had lung metastasis (not shown). The patient was given taxol-based chemotherapy. Follow-up CT (D), 18-FDG PET (E), and 18-FDG PET/CT (F), images show disappearance of the aortocaval lymph node. FIGO indicates International Federation of Gynecology and Obstetrics; 18-FDG, 18 F-flurodeoxyglucose; PET/CT, positron emission tomography/ computed tomography.
can overcome these drawbacks of PET alone and is now being widely used. There are few studies in literature pertaining to role of 18FDG PET/CT for detecting recurrence of carcinoma endometrium (Table 5).17Y19,20Y25,32 Kitajima et al19 in their study found PET alone to be inferior to PET/CT, with lower sensitivity (80% vs. 93%), specificity (80% vs. 93%), and diagnostic accuracy (80% vs. 93%) of former for detecting recurrence. Chung et al20 in their study found the sensitivity, specificity, PPV, NPV, and accuracy of 18-FDG PET/
CT to be 100%, 94.7%, 92.3%, 100%, and 96.8%, respectively for detecting recurrence. In the present study, the results were comparable. 18-FDG PET/CT showed sensitivity of 88.9%, specificity of 93.6%, and accuracy of 91%. 18-FDG PET/CT also had a high PPV (94.1%) for correctly detecting recurrent disease. There were only 3 false-positive results (nonspecific retroperitoneal lymphadenopathy 2 and mediastinal tubercular lymphadenitis 1). These findings underscore the fact that the differentiation between a malignant node and
TABLE 5. Review of Literature 18-FDG PET/PET/CT in Post-Therapy Carcinoma Endometrium Patients for Detection of Recurrence Author Ryu et al17 Kitajima et al25 Kitajima et al18 Kitajima et al19 Park et al32 Chung et al20 Sironi et al21 R Rebollo-Aguirre et al22 Saga et al23
Modality PET PET/CT* PET/CT PET‡ PET/CT* PET PET/CT PET or PET/CT PET/CT PET/CT PET
No. Patients 127 45†
Specificity (%) 88 97* 94 73.9‡ 93.5* 80 93 83.3
PPV (%) 59 V
NPV (%) 100 V
V
V
V
V
Median 52 (35Y73)
Sensitivity (%) 100 90* 83 79.5‡ 90.9* 80 93 100
96
95
Accuracy (%) V 95* 91 76.7‡ 92.2* 80 93 100
Mean 53 Mean 58.9 (37Y79) Mean 63.4 (53Y69)
100 92.9 96
94.7 100 78
92.3 100 89
100 91.7 91
96.8 96 90
Mean 62 (44Y82)
100
88.2
V
V
93.3
Inclusion Criteria Surveillance Suspected recurrence
Age (y) Range Median 52 (27Y71) Median 50 (32Y88)
40†
Suspected recurrence
Median 60 (38Y78)
30
Suspected Recurrence Surveillance/suspected recurrence Suspected recurrence Suspected recurrence Suspected recurrence
Median 59 (38Y82)
88 31 25† 11
PET
21
Belhocine et al24
PET
34
Present study 2011
PET/CT
101
Suspected recurrence/ response to treatment Surveillance/suspected recurrence Suspected recurrence
Mean 65 T 10
96
78
90
89
91
Median 56 (35Y77)
88.9
93.6
94.1
88
91
*Contrast enhanced PET/CT. † Number of carcinoma endometrium patients in a mixed population of carcinoma cervix and carcinoma endometrium. ‡ PET component of PET/CT was evaluated separately. 18-FDG indicates 18F-flurodeoxyglucose; PET/CT, positron emission tomography-computed tomography; PPV, positive predictive value; NPV, negative predictive value.
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focally increased glucose metabolism due to a reactive node remains problematic even with PET/CT. Also PET/CT has a high NPV (88%) in ruling out recurrence. There were only 6 false-negative studies. Among these, 2 were due to lung metastases, which were detected with CECT. This might be due to lower resolution of CT component of our PET/CT and respiratory motion with partial volume effect causing underestimation of 18-FDG uptake. One was small paraaortic lymph node (0.8 cm), which was picked up with CECT and confirmed with FNAC. Small size and physiological tracer activity in bowel wall overshadowed the finding. Two were local recurrences, which were confirmed with clinical follow-up. One patient had bone metastasis to third lumbar vertebra, which was demonstrated with bone scan and confirmed with follow-up PET/CT after 8 months. These may be because of the fact that PET/CT cannot detect the microscopic disease. It takes a certain number (104Y107) of tumor cells with increased abnormal glucose metabolism to be present for them to be detected by PET/CT imaging.33 In our study, intravascular contrast agents were not used in the CT imaging protocol. Kitajima et al18 conducted a study on a mixed population of carcinoma cervix and carcinoma endometrium patients (n = 40) with suspected recurrence using contrastenhanced (ce) PET/CT. They concluded that cePET-CT is highly sensitive (90.9%) and specific (93.5%) for detecting recurrence in these patients. In another study by Kitajima et al,25 cePET-CT showed a higher sensitivity (90% vs. 83%), specificity (97% vs. 94%), and accuracy (95% vs. 91%) compared with unenhanced low-dose PET/CT. However, Sensitivity, specificity, and accuracy did not significantly differ between 2 methods (McNemar test, P = 0.48, P = 0.48, and P = 0.13, respectively). The results of present study are also similar (sensitivity 88.9%, specificity 93.6%, and accuracy 91%). Thereby, it may be inferred that unenhanced 18-FDG PET/CT may be sufficient for patients with suspected recurrent endometrial carcinoma. Moreover, earlier experimental and clinical investigations34 suggested that local accumulation of CT contrast agents may introduce artifacts into the PET emission data. In the present study, we also compared the diagnostic efficacy of 18-FDG PET/CT with CI (CECT/MRI/USG/bone scan) performed within an interval of 4 weeks in 76 patients. PET/CT showed a better diagnostic performance as compared with CI. Although the sensitivity of PET/CT was similar to CI (89.5% vs. 85.1%), the former showed much higher specificity (96.4% vs. 62%) and accuracy (92.1% vs. 76.3%). PET/CT also has a higher PPV (97.7% vs. 78.4%) and NPV (84.3% vs. 72%) compared with CI. However, McNemar test did not reveal any significant difference between diagnostic accuracies of the 2 modalities on per patient basis (P = 0.210). This finding may be because of late presentation of disease in our study population. PET/CT detected locoregional disease in 12 patients with negative CI. Similarly, in 7 patients, PET/CT detected previously unknown metastasis thereby changing the therapy plan from locoregional to systemic palliative therapy. Based on the findings of our study, 18-FDG PET/CT seems to be highly suited for detection of recurrence in post-therapy carcinoma endometrium patients with suspected recurrence. It allows distinction between a local and a disseminated recurrence pattern, which assists in selection of the therapeutic option. Few limitations of the present investigation should be taken into account. First, histopathological confirmation was not available for all lesions. However, this was not technically or ethically feasible. Second, follow-up period of 6 months is not long enough. Third, this is a retrospective study. A prospective study with longer follow-up period and histopathological correlation might better address the issue.
CONCLUSION 18-FDG PET/CT is a highly sensitive and specific modality for detecting recurrence in post-therapy patients of carcinoma endome654
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trium with suspected recurrence. It is more specific than CI. 18-FDG PET/CT has a high diagnostic yield in the detection of recurrent disease, even in a population with a high prevalence of infectious diseases. REFERENCES 1. Morrow CP, Bundy BN, Kurman RJ, et al. Relationship between surgicalpathological risk factors and outcome in clinical stage I and II carcinoma of the endometrium: a Gynecologic Oncology Group study. Gynecol Oncol. 1991;40: 55Y65. 2. Irvin WP, Rice LW, Berkowitz RS. Advances in the management of endometrial adenocarcinoma. A review. J Reprod Med. 2002;47:173Y189. 3. Aalders JG, Abeler V, Kolstad P. Recurrent adenocarcinoma of the endometrium: a clinical and histopathological study of 379 patients. Gynecol Oncol. 1984;17:85Y103. 4. Kao MS. Management of recurrent endometrial cancer. Chang Gung Med J. 2004;27:639Y645. 5. Pazdur R, Coia LR, Hoskins WJ, et al. Cancer Management: A Multidisciplinary Approach. 5th ed. New York, NY: PRR; 2001. 6. Benedet JL, Bender H, Jones H III, et al. FIGO staging classifications and clinical practice guidelines in the management of gynecologic cancers. FIGO Committee on Gynecologic Oncology. Int J Gynaecol Obstet. 2000;70: 209Y262. 7. Jeyarajah AR, Gallagher CJ, Blake PR, et al. Long-term follow-up of gonadotrophin-releasing hormone analog treatment for recurrent endometrial cancer. Gynecol Oncol. 1996;63:47Y52. 8. Moore TD, Phillips PH, Nerenstone SR, et al. Systemic treatment of advanced and recurrent endometrial carcinoma: current status and future directions. J Clin Oncol. 1991;9:1071Y1088. 9. Huang HJ, Lai CH, Tsai CS, et al. Radical resection and intraoperative radiotherapy for a recurrent endometrial cancer after prolonged remission following aggressive salvage therapy: case report. Chang Gung Med J. 1999;22: 654Y659. 10. Connor JP, Andrews JI, Anderson B, et al. Computed tomography in endometrial carcinoma. Obstet Gynecol. 2000;95:692Y696. 11. Cherchi PL, Dessole S, Ruiu GA, et al. The value of serum CA 125 and association CA 125/CA 19Y9 in endometrial carcinoma. Eur J Gynaecol Oncol. 1999;20:315Y317. 12. Manfredi R, Mirk P, Maresca G, et al. Local-regional staging of endometrial carcinoma: role of MR imaging in surgical planning. Radiology. 2004;231: 372Y378. 13. Kinkel K, Ariche M, Tardivon AA, et al. Differentiation between recurrent tumor and benign conditions after treatment of gynecologic pelvic carcinoma: value of dynamic contrast-enhanced subtraction MR imaging. Radiology. 1997; 204:55Y63. 14. Kluetz PG, Meltzer CC, Villemagne VL, et al. Combined PET/CT Imaging in Oncology. Impact on Patient Management. Clin Positron Imaging. 2000;3: 223Y230. 15. Yen TC, Ng KK, Ma SY, et al. Value of dual-phase 2-fluoro-2-deoxy-Dglucose positron emission tomography in cervical cancer. J Clin Oncol. 2003; 21:3651Y3658. 16. Zimny M, Siggelkow W, Schroder W, et al. 2-[lsqb]Fluorine-18[rsqb]-fluoro-2deoxy-D-glucose positron emission tomography in the diagnosis of recurrent ovarian cancer. Gynecol Oncol. 2001;83:310Y315. 17. Ryu SY, Kim K, Kim Y, et al. Detection of recurrence by 18F-FDG PET in patients with endometrial cancer showing no evidence of disease. J Korean Med Sci. 2010;25:1029Y1033. 18. Kitajima K, Murakami K, Yamasaki E, et al. Performance of integrated FDGPET/contrast-enhanced CT in the diagnosis of recurrent uterine cancer: comparison with PET and enhanced CT. Eur J Nucl Med Mol Imaging. 2009;36: 362Y372. 19. Kitajima K, Murakami K, Yamasaki E, et al. Performance of FDG-PET/CT in the diagnosis of recurrent endometrial cancer. Ann Nucl Med. 2008;22: 103Y109. 20. Chung HH, Kang WJ, Kim JW, et al. The clinical impact of [(18)F]FDG PET/ CT for the management of recurrent endometrial cancer: correlation with clinical and histological findings. Eur J Nucl Med Mol Imaging. 2008;35: 1081Y1088. 21. Sironi S, Picchio M, Landoni C, et al. Post-therapy surveillance of patients with uterine cancers: value of integrated FDG PET/CT in the detection of recurrence. Eur J Nucl Med Mol Imaging. 2007;34:472Y479.
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Clinical Nuclear Medicine
& Volume 37, Number 7, July 2012
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PET/CT for Recurrent Carcinoma Endometrium
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