18F-FDG PET in the management of endometrial cancer

PET Imaging of Estrogen Receptors for Gynecological Tumors

ABSTRACT

In the past few decades, PET with 18F-FDG has been used for the diagnosis of gynecological malignancies and is considered to be superior to conventional imaging methods in diagnostic accuracy for detecting metastatic lesions and local recurrence and in evaluating the treatment response. On the other hand, several gynecological tumors, such as endometrial cancer and leiomyoma, and breast cancer are estrogen-dependent, in which estrogen is essential for their development and progression. 18F-FES is an 18F-labeled compound of estradiol, the most bioactive type of estrogen, and 18F-FES PET has been well-established for diagnosis, staging, and posttherapeutic follow-up in patients with estrogen receptor-positive breast cancer. Compared with in vitro assessment of tumor biopsy material, PET imaging has the advantages of being able to measure in vivo tumor behavior, characterize the entire tumor burden, and capture the heterogeneity of the tumor phenotype. In this article, we review the phenotyping of estrogen-related gynecological tumors other than breast cancer using 18F-FES PET and demonstrate the additional value of 18F-FES PET to 18F-FDG PET in their diagnosis and prognostication. Moreover, promising PET tracers other than 18F-FES and 18F-FDG for the evaluation of estrogen-related gynecological tumors are introduced.

Management of inoperable endometrial cancer

Some endometrial cancer (EMC) patients are not good candidates for primary surgery. The three major types of treatment for inoperable EMC are radiation therapy, chemotherapy, or their combination as neoadjuvant treatment before surgery. Radiation therapy alone (of different modes) has been used as the sole definitive therapeutic modality, particularly for early-stage disease that is limited to the uterine body and cervix with or without parametrial invasion. The most common treatment modality is neoadjuvant treatment before surgery. Postoperative adjuvant treatment is also occasionally used, depending mainly on the sites of the disease and the results of surgery. Data on neoadjuvant hormonal or radiation therapy are limited, with studies focusing on laboratory outcomes or having only a small number of patients. Most neoadjuvant treatments before surgery involved chemotherapy and fewer combined chemoradiotherapy. Surgery was generally performed, particularly in patients who had shown responses or at least stable disease to neoadjuvant treatment. Perioperative outcomes after neoadjuvant treatment were superior to those after primary surgery, whereas survival data were still inconsistent. Features that had or tended to have a favorable prognosis were younger age, early-stage disease, response to neoadjuvant treatment, low preoperative cancer antigen-125 level, and optimal surgery. Among different modalities of neoadjuvant treatment, which has become a frequent mode of treatment, neoadjuvant chemotherapy was more common than radiation therapy alone or chemoradiation.

FDG-PET/CT and Para-Aortic Staging in Endometrial Cancer. A French Multicentric Study

BACKGROUND

FDG-PET/CT is a noninvasive examination that could be helpful for the management of endometrial cancer. The aim of this study was to evaluate the performance of FDG-PET/CT in assessing para-aortic lymph-node involvement in high-risk endometrial cancer.

METHODS

We performed a retrospective multicenter study including all patients who had a high-risk endometrial cancer with a preoperative FDG-PET/CT and a para-aortic lymphadenectomy (PAL) between 2009 and 2019. The main objective was to evaluate the overall performance of FDG-PET/CT. The secondary objectives were to evaluate its performances according to the histological type and according to FDG-PET/CT date (before or after hysterectomy), and to compare its overall performance with that of the MRI scan.

RESULTS

We included 200 patients from six different centers. After the false positive FDG-PET/CT was reread by nuclear physicians, FDG-PET/CT had a sensitivity of 61.8%, a specificity of 89.7%, a positive predictive value of 69.4%, a negative predictive value of 86.1%, and an AUC of 0.76. There were no statistically significant differences in the performances according to either histological type and or FDG-PET/CT date. The sensitivity of FDG-PET/CT was better than that of MRI (p < 0.01), but the specificity was not (p = 0.82).

CONCLUSION

Currently, FDG-PET/CT alone cannot replace PAL for the lymph node evaluation of high-risk endometrial cancers. It seems essential to reread it in multidisciplinary meetings before validating the therapeutic management of patients, particularly in the case of isolated para-aortic involvement.

Clinical and prognostic value of 18F-FDG PET/CT in recurrent endometrial carcinoma

PURPOSE

Endometrial carcinoma (EC) is a cancer with a good overall prognosis, except in cases of recurrent or advanced EC. The aim of this study was to assess the diagnostic performance, the prognostic value and the impact on therapeutic management of ¹⁸F-FDG PET/CT in suspected recurrent EC.

MATERIALS AND METHODS

We retrospectively evaluated 157 patients with histologically proven EC and restaging ¹⁸F-FDG PET/CT for suspected recurrence. The PET images were analyzed visually and semi-quantitatively by measuring SUVmax, MTV and TLG. A combination of clinical/imaging follow-up and/or histopathology was taken as reference standard. Progression-free survival (PFS) and overall survival (OS) were computed using Kaplan-Meier curves.

RESULTS

Seventy-nine patients had positive ¹⁸F-FDG PET/CT showing the presence of at least one hypermetabolic lesion consistent with recurrence, while the remaining 78 were negative. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of ¹⁸F-FDG PET/CT were 96%, 99%, 99%, 96%, 97%, respectively, and were higher compared to conventional imaging: 97%, 62%, 72%, 96%, 80%. After a mean follow-up of 39months, relapse/progression occurred in 58 patients and death in 37 with an average time of 22.1 and 27.6months, respectively. A positive ¹⁸F-FDG PET/CT and advanced FIGO stage were significantly associated with shorter PFS and OS. PET/CT results had a significant impact on therapeutic approach in 33 patients: avoiding unnecessary therapies in 28 and modifying therapy in 5.

CONCLUSIONS

¹⁸F-FDG PET/CT has a very good diagnostic performance in patients with suspected recurrent EC and has an important prognostic value in assessing PFS and OS. Moreover, PET/CT allowed for a change in treatment decision in about 20% of cases.

Different imaging techniques for the detection of pelvic lymph nodes metastasis from gynecological malignancies: a systematic review and meta-analysis

OBJECTIVE

This study aimed to evaluate the diagnostic performance of different imaging techniques and the corresponding diagnostic criteria for preoperative detection of pelvic lymph node metastasis from gynecological carcinomas.

METHODS

Six databases were systematically searched for retrieving eligible studies. Study inclusion, data extraction and risk of bias assessment were performed by 2 reviewers independently. STATA 14.0 was used to perform the meta-analysis.

RESULTS

Eighty eligible studies were collected. The pooled sensitivity, specificity, and area under curve (AUC) of CT, MRI and DWI were 47%, 93%, 0.7424; 50%, 95%, 0.8039 and 84%, 95%, 0.9523 respectively. As regards PET, PET-CT and US, the pooled sensitivity, specificity and AUC were 56%, 97%, 0.9592; 68%, 97%, 0.9363 and 71%, 99%, 0.9008 respectively. The summary receiver operating characteristic (SROC) curve indicated that the systematic diagnostic performances of PET, PET-CT, DWI were superior to other imaging modalities.

CONCLUSIONS

The present work demonstrated that DWI, PET, PET-CT were the top-priority consideration of imaging modalities for detecting metastatic pelvic lymph node in gynecological carcinoma. DWI was recommended as the first choice for metastasis exclusion and all the other imaging techniques including CT and MRI were suitable for metastasis conformation. However, for the early stage lymph node malignancy, PET or PET-CT could represent a better choice. More studies exploring the diagnostic efficacy of detailed criteria are required in the future.

Comparison of MRI and 18F-FDG PET/CT in the preoperative evaluation of uterine carcinosarcoma

OBJECTIVE

To compare the validities of magnetic resonance imaging (MRI) and (18)F-fluoro-deoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) in preoperative evaluation of uterine carcinosarcoma.

METHODS

Pathologic results of primary tumor lesions and paraaortic and pelvic lymph node (LN) areas were compared with the preoperative image findings. Differences in the validity parameters of both images were compared using McNemar test.

RESULTS

For detecting primary tumor lesions (n=56), the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for (18)F-FDG PET/CT versus MRI were 98.1% versus 98.1% (P=1.000), 33.3% versus 100% (P=0.157), 94.6% versus 98.2% (P=0.500), 96.3% versus 100%, and 50% versus 75%, respectively. For paraaortic LN areas, the values were 77.8% versus 51.9% (P=0.016), 90.2% versus 100% (P=0.025), 85.9% versus 83.3% (P=0.774), 80.8% versus 100%, and 88.5% versus 79.7%, respectively. For pelvic LN areas, the values were 61.1% versus 50% (P=0.125), 86.8% versus 89.5% (P=0.727), 78.6% versus 76.8% (P=0.774), 68.8% versus 69.2%, and 82.5% versus 79.1%, respectively. For extrauterine disease, the patient-based values for (18)F-FDG PET/CT were 100%, 78.9%, 85.7%, 69.2%, and 100%, respectively.

CONCLUSION

In patients with uterine carcinosarcoma, (18)F-FDG PET/CT is comparable to MRI in detecting primary uterine lesions. For predicting LN metastases, though (18)F-FDG PET/CT might be insufficient for replacing lymphadenectomy or MRI, it might allow lymphadenectomy to be omitted in poor surgical candidates. For detecting extrauterine metastases, it could also be useful to identify unsuspected disease.

Gynecologic oncologic imaging with PET/CT

FDG-PET/CT has been evaluated in a variety of gynecologic malignancies in a variety of settings and is approved by the Centers for Medicare & Medicaid Services for the initial and subsequent treatment strategies of these malignancies. Cervical cancer is typically very FDG avid, and FDG-PET/CT appears to be most valuable for initial staging, radiation therapy planning, and detection of recurrent disease. For ovarian cancer, the most value of FDG-PET/CT appears to be for detecting recurrent disease in the setting of rising CA-125 level and negative or equivocal anatomical imaging studies. Initial studies evaluating response to therapy are promising and further work in this area is needed. FDG uptake in both nonmalignant and physiological processes in the pelvis can make interpretation of FDG-PET/CT in this region challenging and knowledge of these entities and patterns can avoid misinterpretation. Some of the most common findings relate to the cyclic changes that occur as part of the menstrual cycle in premenopausal women. Mucinous tumors and low-volume or peritoneal carcinomatosis are causes of false-negative results on FDG-PET/CT studies. As new tracers are developed, comparisons with patient outcomes and standards of care (eg, FDG-PET/CT) will be needed.

Treatment failure in endometrial carcinoma

OBJECTIVE

Our aim was to investigate the outcomes and prognostic factors after treatment failure of endometrial cancer.

METHODS

A total of 923 endometrial cancer patients were treated between 2000 and 2010, of which 109 experienced treatment failure. Treatment failure was defined as relapse after complete removal of all cancerous lesions or persistent/progressive disease despite treatment. Variables including clinicopathological features at initial treatment, type of primary treatment, failure pattern, salvage treatment, and outcomes were analyzed. Kaplan-Meier survival curves were compared with log-rank test. Cox proportional hazards regression model was used to identify significant prognostic factors.

RESULTS

Eighteen cases with persistent/progressive disease died shortly from primary diagnosis (1-23 months). The remaining 91 patients had recurrences in vagina only (8.8%), pelvis (3.3%), distant (63.7%), and combined pelvic-distant sites (24.2%). Median time to recurrence was 13.3 months (3.2-97.2 months). The median follow-up after recurrence of survivors was 60.5 months (10.6-121.7 months). The median survival after recurrence (SAR) was 20.3 months (1.9-121.7 months) with 5-year SAR rate of 32.4%. By multivariate analysis, initial stage II to IV (hazards ratio [HR], 3.41; 1.53-7.60; P = 0.003), type II histology (HR, 2.50; 1.28-4.90; P = 0.008), positive peritoneal cytology (HR, 2.23; 1.07-4.68; P = 0.033), and recurrence at multiple sites (HR, 2.51; 1.30-4.84; P = 0.006) were significantly associated with poor SAR. The 5-year SAR rates in patients with solitary vaginal, nodal/liver, or pulmonary/bony recurrence were 83.3%, 50.5%, and 24.2%, respectively. Ten cases with resectable or irradiatable recurrence at multiple sites or multiple relapses attained SAR greater than 5 years after multimodality salvage therapy.

CONCLUSIONS

Initial stage II to IV, type 2 histology, positive cytology, and recurrence at multiple sites were significant poor prognostic factors. Curative intent salvage therapy remains a viable option for cases with resectable or irradiatable multiple recurrences and solitary distant metastasis.

The Accuracy of Integrated [(18)F] Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography in Detection of Pelvic and Para-aortic Nodal Metastasis in Patients with High Risk Endometrial Cancer

Lymph nodal (LN) metastasis is the most important prognostic factor in high-risk endometrial cancer. However, the benefit of routine lymphadenectomy in endometrial cancer is controversial. This study was conducted to assess the accuracy of [¹⁸F] fluorodeoxyglucose-positron emission tomography/computed tomography ([¹⁸F] FDG-PET/CT) in detection of pelvic and para-aortic nodal metastases in high-risk endometrial cancer. 20 patients with high-risk endometrial carcinoma underwent [¹⁸F] FDG-PET/CT followed by total abdominal hysterectomy, bilateral salpingo-oophorectomy and systematic pelvic lymphadenectomy with or without para-aortic lymphadenectomy. The findings on histopathology were compared with [¹⁸F] FDG-PET/CT findings to calculate the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of [¹⁸F] FDG-PET/CT. The pelvic nodal findings were analyzed on a patient and nodal chain based criteria. The para-aortic nodal findings were reported separately. Histopathology documented nodal involvement in two patients (10%). For detection of pelvic nodes, on a patient based analysis, [¹⁸F] FDG-PET/CT had a sensitivity of 100%, specificity of 61.11%, PPV of 22.22%, NPV of 100% and accuracy of 65% and on a nodal chain based analysis, [¹⁸F] FDG-PET/CT had a sensitivity of 100%, specificity of 80%, PPV of 20%, NPV of 100%, and accuracy of 80.95%. For detection of para-aortic nodes, [¹⁸F] FDG-PET/CT had sensitivity of 100%, specificity of 66.67%, PPV of 20%, NPV of 100%, and accuracy of 69.23%. Although [¹⁸F] FDG-PET/CT has high sensitivity for detection of LN metastasis in endometrial carcinoma, it had moderate accuracy and high false positivity. However, the high NPV is important in selecting patients in whom lymphadenectomy may be omitted.

Which imaging technique should we use in the follow up of gynaecological cancer?

Follow-up routines after gynaecological cancer vary. The optimal approach is unknown, and no randomised-controlled trials comparing surveillance protocols have been published. In this chapter, we summarise the diagnostic performance of ultrasound, computed tomography, and magnetic resonance imaging in the follow up of women treated for ovarian or uterine cancers. Computed tomography is today the standard imaging method for the follow up of women treated for endometrial, cervical, or ovarian cancer. Six-monthly or annual follow-up examinations have not been shown to positively affect survival. Instead, a combination of transvaginal and transabdominal ultrasound examination with clinical examination might be a more cost-effective strategy for early detection of recurrence. Positron-emission tomography might play a role in women with clinical or serological suspicion of recurrence but without evidence of disease at conventional diagnostic imaging. To create guidelines, more studies, preferably randomised-controlled trials, on follow-up strategies are needed.

Positron emission tomography in gynecological malignancies

Positron emission tomography (PET) is a functional diagnostic imaging technique. F-18 fluoro-2-deoxy-d-glucose (FDG) is a commonly used radiopharmaceutical that is an analog of glucose. PET with FDG is now the standard of care in initial staging, monitoring the response to the therapy and management of various cancers. There is not sufficient data to support the use of PET in the initial diagnosis of cervical cancer; however, FDG-PET has a role in initial staging in the detection of distant metastases in patients with cervical cancer. PET has limited value in lesion localization in early stages of ovarian cancer, but plays a significant role in identifying recurrent tumors in patients with rising tumor markers. In this article, the clinical application of PET in gynecological malignancies is reviewed.

Tailoring systematic lymphadenectomy in high-risk clinical early stage endometrial cancer: the role of 18F-FDG PET/CT

OBJECTIVES

To evaluate the role of FDG PET/CT in the preoperative N-staging of high-risk clinical stage I endometrial cancer. The correlation between the metabolic characteristics of endometrial tumor uptake as predictors of a) lymph-node (LN) metastases and b) recurrence, was also evaluated.

METHODS

Seventy-six high-risk (G2 with deep myometrial invasion, G3, serous/clear-cell carcinoma) clinical stage I endometrial cancer patients underwent preoperative PET/CT scan followed by total hysterectomy, bilateral salpingo-oophorectomy and lymphadenectomy. PET/CT images were analyzed and correlated to histological findings. Maximal and mean standardized uptake value (SUVmax, SUVmean), metabolic tumor volume (MTV), total lesion glycolysis (TLG, defined as the product between SUVmean and MTV) of endometrial lesions were calculated and correlated to: a) presence of LN metastases, b) recurrences.

RESULTS

PET/CT resulted positive at LNs in 12/76 patients: 11/12 truly positive, 1/12 falsely positive. Conversely PET/CT was negative in 64/76 patients: 61/64 truly negative and 3/64 falsely negative. On pt-based analysis, sensitivity, specificity, accuracy, positive and negative predictive value of PET/CT in detecting LN metastases were 78.6%, 98.4%, 94.7%, 91.7%, 95.3%, respectively. A significant association was found between the presence of LN metastases and SUVmax (p=0.038), MTV (p=0.007), TLG (p=0.003) of the primary tumor. No correlations were found between the metabolic parameters and relapse (median follow-up 25.4months).

CONCLUSIONS

In high-risk clinical stage I endometrial cancer FDG PET/CT demonstrated moderate sensitivity, high specificity and accuracy for the nodal status assessment. SUVmax, MTV and TLG of the primary tumor are significantly correlated to LN metastases, while none of these parameters is predictor of recurrence.

Prediction of lymph node and distant metastasis in patients with endometrial carcinoma: a new model based on demographics, biochemical factors, and tumor histology

OBJECTIVE

To develop a model that might predict the probability of lymph node and distant metastasis (stages IIIC-IV) in endometrial carcinoma.

METHODS

We studied 774 patients with endometrial carcinoma treated in a single institution. Demographic factors, biochemical factors and preoperative tumor characteristics, identified as potential risk factors for advanced carcinoma in unadjusted analyses, were used to create a logistic regression model with lymph node and distant metastasis as the dependent variable. Statistically significant odds ratios in the regression model were rounded to the nearest whole number. These rounded values were the estimated weights for each factor that were summed to generate a score that might predict the probability of stage IIIC-IV carcinoma.

RESULTS

Biochemical factors and preoperative tumor characteristics predicted lymph node and distant metastasis in the regression model, whereas demographic factors were without effect. The score combining weighted risk factors was: (2 × leukocytosis)+(3 × thrombocytosis)+(7 × elevated CA125)+(4 × high-risk histology). The area under curve (AUC) for this total score was 0.823, with 71.6% sensitivity, 75.2% specificity, 25.9% positive predictive value, and 95.7% negative predictive value, using 6 as cut-point. After excluding stage IV carcinomas from the dataset, the AUC was 0.813 for the total score in predicting nodal involvement (P=0.82 vs. total score in predicting stage IIIC-IV carcinomas in the complete dataset).

CONCLUSIONS

Based on the high negative predictive value, this prediction model could be applied for identifying patients who may not benefit from lymphadenectomy for endometrial carcinoma staging.

Uterine papillary serous cancer: a review of the literature

OBJECTIVE

Uterine papillary serous carcinoma (UPSC) represents a distinct subtype of endometrial cancer. UPSC is less common than endometrioid carcinoma (ECC) but accounts for a disproportionate number of uterine cancer related deaths. This article critically reviews the literature pertinent to the pathology, pathogenesis, diagnosis, management, and outcome of patients with UPSC.

METHODS

MEDLINE was searched for all research articles published in English between January 1, 1967-January 1, 2012 which reported on patients diagnosed with UPSC. Given the rarity of this tumor, studies were not limited by design or number of reported patients.

RESULTS

UPSC represents a histologically aggressive subtype of endometrial cancer. It commonly presents with extra uterine disease involvement which can be identified by comprehensive surgical staging. Optimal cytoreduction and systemic platinum/taxane-based adjuvant therapy appear to confer a survival advantage.

CONCLUSIONS

UPSC is a biologically distinct entity, different from ECC. Future studies should explore the role of targeted therapies in the management of UPSC.

Controversies in the management of endometrial carcinoma: an update

Endometrial carcinoma is the commonest type of female genital tract malignancy in the developed countries. Endometrial carcinoma is usually confined to the uterus at the time of diagnosis and as such usually carries an excellent prognosis with high curability. Our understanding and management of endometrial cancer have continuously developed. Current controversies focus on screening and early detection, the extent of nodal surgery, and the changing roles of radiation therapy and chemotherapy and will be discussed in this paper.

[FDG-PET and endometrial cancer]

FDG-PET is widely used for the diagnosis, the staging and the search for recurrence of many tumors. However, there are currently no recommendations for its use in endometrial cancer. This article is an update of the literature data to enable everyone to form an opinion on the subject. Future prospects are considered.

The value of FDG-PET/CT in the post-treatment evaluation of endometrial carcinoma: a comparison of PET/CT findings with conventional imaging and CA 125 as a tumour marker

OBJECTIVES

This retrospective study was designed to assess the value of positron emission tomography/computed tomography imaging (PET/CT) in the post-treatment evaluation of the patients with endometrial carcinoma and to compare PET/CT scan with conventional imaging (CI) including computed tomography (CT), ultrasonography (US) and magnetic resonance imaging (MRI) and CA 125 with both 20U/ml and 35U/ml cut-off values.

MATERIALS AND METHODS

A total of 31 patients who were treated for histopathologically proven endometrial adenocarcinoma, underwent PET/CT examination for restaging and suspected recurrence. Thirty five PET/CT studies were performed in 31 patients. Lesion status was determined on the basis of clinical follow-up including radiological imaging (follow-up CT scan) at least 6 months and response to therapy.

RESULTS

Of the 35 PET/CT studies, 13 (37%) studies were positive, whereas 22 (63%) of them were negative. On study-based analysis the overall sensitivity, specificity, accuracy for PET/CT imaging were 100%, 96% and 97%, respectively. The corresponding information for CI were 46%, 87% and 74%, for CA 125 (cut off=20U/ml) measurement were 45%, 88% and 74%, and for CA 125 (cut off=35U/ml) measurement were 27%, 100% and 78%, respectively. On lesion-based analysis, PET/CT revealed only one false positive case. In none of 21 patients with negative 22 PET/CT studies, no subsequent clinical or radiological recurrences were observed with a follow-up of at least 6 months.

CONCLUSION

FDG-PET/CT is found more useful modality than CI and CA 125 in the evaluation of post-treatment endometrial carcinoma patients, for suspected recurrence.

Analysis of various malignant neoplasms detected by FDG-PET cancer screening program: based on a Japanese Nationwide Survey

OBJECTIVE

The most distinctive feature of FDG-PET cancer screening program is the ability to find various kinds of malignant neoplasms in a single test. The aim of this survey is to clarify the range and frequency of various malignant neoplasms detected by FDG-PET cancer screening performed in Japan.

METHODS

"FDG-PET cancer screening" was defined as FDG-PET or positron emission tomography and computed tomography (PET/CT) scan with or without other tests performed for cancer screening of healthy subjects. This survey was based on a questionnaire regarding FDG-PET cancer screening. We analyzed the situation of 9 less frequently found malignant neoplasms including malignant lymphoma, malignancy of head and neck, esophagus, hepatobiliary and gallbladder, pancreas, kidney, cervical and uterine, ovary, and bladder.

RESULTS

The detailed information of subjects with the suspected 9 kinds of malignant neoplasms mentioned above in the FDG-PET cancer screening program was studied in a total of 1,219 cases from 212 facilities. A statistical significance between PET/CT and PET was found in relative sensitivity and PPV for renal cell cancer. Malignant lymphoma was frequently of indolent type, suspected head and neck cancers had many false-positive results, and pancreatic cancer detected in this program was often in the advanced stage even in asymptomatic subjects. The recommendation of combined screening modality to PET or PET/CT was as follows: gastric endoscopy for assessing early esophageal cancer; abdominal ultrasound for screening hepatobiliary and gallbladder cancer; pelvic magnetic resonance imaging for assessing gynecological and pelvic cancers; and the CA125 blood test for screening ovarian cancer. Delayed image was helpful depending on the type of suspected malignant neoplasm.

CONCLUSION

We analyzed various types of malignant neoplasms detected by the FDG-PET cancer screening program and presented recommended combination of examinations to cover FDG-PET and PET/CT.

PET/CT Imaging in Gynecologic Malignancies Other than Ovarian and Cervical Cancer

Fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) is an imaging modality used for staging, assessing response to therapy, and diagnosis of recurrent cervical and ovarian cancer. The potential role of FDG-PET/CT in other gynecologic malignancies such as endometrial cancer, uterine sarcomas, vaginal, and vulvar cancer has not been fully explored.

Detection of recurrence by 18F-FDG PET in patients with endometrial cancer showing no evidence of disease

This study assessed the feasibility of F-18-fluorodeoxyglucose positron-emission tomography ((18)F-FDG PET) in the post-therapy surveillance for patients with endometrial cancer showing no evidence of disease (NED). From April 1997 to June 2007, 127 patients with endometrial cancer showing NED were performed (18)F-FDG PET scan. The feasibility of (18)F-FDG PET for the early detection of recurrence in patients with endometrial cancer was evaluated retrospectively. Of the 127 patients, 32 patients showed positive lesions on (18)F-FDG PET scan. Nineteen (19/127 cases, 15%) of them were confirmed to have a recurrence clinically or histologically. The sensitivity, specificity and positive and negative predictive value of (18)F-FDG PET for detecting recurrences in patients with endometrial cancer were 100%, 88%, 59% and 100%, respectively. In conclusion, (18)F-FDG PET may be a useful method for the post-therapy surveillance in patients with endometrial cancer.

Controversies in the management of endometrial carcinoma

Endometrial carcinoma is the most common type of female genital tract malignancy. Although endometrial carcinoma is a low grade curable malignancy, the condition of the disease can range from excellent prognosis with high curability to aggressive disease with poor outcome. During the last 10 years many researches have provided some new valuable data of optimal treatments for endometrial carcinoma. Progression in diagnostic imaging, radiation delivery systems, and systemic therapies potentially can improve outcomes while minimizing morbidity. Firstly, total hysterectomy and bilateral salphingo-oophorectomy is the primary operative procedure. Pelvic lymhadenectomy is performed in most centers on therapeutic and prognostic grounds and to individualize adjuvant treatment. Women with endometrial carcinoma can be readily segregated intraoperatively into “low-risk” and “high-risk” groups to better identify those women who will most likely benefit from thorough lymphadenectomy. Secondly, adjuvant therapies have been proposed for women with endometrial carcinoma postoperatively. Postoperative irradiation is used to reduce pelvic and vaginal recurrences in high risk cases. Chemotherapy is emerging as an important treatment modality in advanced endometrial carcinoma. Meanwhile the availability of new hormonal and biological agents presents new opportunities for therapy.

Advances in imaging techniques for diagnosis of endometrial cancer

IMPORTANCE OF THE FIELD

Endometrial cancer is the most common gynecologic malignancy diagnosed in Western countries, and its care is rapidly evolving towards more personalized treatment recommendations to improve outcome and minimize toxicity and cost. Evaluation of the accuracy of preoperative assessment by imaging of the depth of myometrial invasion, cervical invasion and nodal metastasis is very important for optimizing surgical procedures and therapeutic strategies.

AREAS COVERED IN THIS REVIEW

This review focuses on research published within the past decade and draws extensively on the texts and summaries of the articles referenced to imaging of the depth of myometrial invasion, cervical invasion and nodal metastasis in endometrial cancer. Less recent citations are also included when deemed useful to provide background information.

WHAT THE READER WILL GAIN

The reader will be introduced to recent advances, techniques and applications of system approach to assess by imaging of endometrial cancer. The reader will learn fundamental research principles and tasks required in the implementation of these approaches and applications. The reader will gain a better understanding of the role of imaging for endometrial cancer, as well as of potential opportunities and advances.

TAKE HOME MESSAGE

The utility of new techniques, including contrast material-enhanced dynamic magnetic resonance imaging (MRI), diffusion-weighted magnetic resonance imaging, higher Tesla machines, MRI using nanoparticle contrast media, and positron-emission tomography with (18)F-deoxy-glucose and/or radiotracers of 16α-[(18)F]fluoro-17β-estradiol binding to the estrogen receptor are promising methods, although some limitations remain. Further advances in molecular imaging technology will eventually overcome these current limitations in diagnosis of endometrial cancer.

Present and future of PET and PET/CT in gynaecologic malignancies

OBJECTIVES

To review the published data in literature on patients affected by gynaecological malignancies to establish the role of (18)F-FDG positron emission tomography (PET) and PET/CT in comparison to conventional imaging (CI).

MATERIALS AND METHODS

All papers specifically addressed to the role of (18)F-FDG PET and PET/CT in gynaecological malignancies published on PubMed/Medline, in abstracts from the principal international congresses, in the guidelines from national Societies that had appeared in literature until November 2009 were considered for the purpose of the present study.

RESULTS AND CONCLUSIONS

The use of (18)F-FDG PET, and even more of (18)F-FDG PET/CT, is increasing in the follow up of patients with gynaecologic malignancies and suspected recurrent disease: there is evidence in the literature that (18)F-FDG PET/CT has a higher sensitivity than CI in depicting occult metastatic spread. An interesting issue is represented by patients with ovarian cancer with an increase of the specific biomarker, CA-125, and negative/inconclusive findings at CI. The use of (18)F-FDG PET in differential diagnosis and staging is more controversial, but there is some evidence that a baseline PET examination performed before commencing therapy, for staging purpose, is also useful to evaluate the response to chemoradiation treatment. In several papers it has been suggested a relevant role of (18)F-FDG PET/CT in evaluating the entity of response to treatment and therefore to plan the subsequent therapeutic strategy.

[Is there an interest in para-aortic lymphadenectomy in operable endometrial cancer?]

The indication and extent of lymph node dissection in the surgical management of endometrial cancer remains controversial especially concerning the para-aortic lymph nodes. The therapeutic benefit of the lymph node dissection is criticized mainly for low-risk patients for extra-uterine spread. Surgically staging patients is the best method to predict node involvement and it allows an optimal decision for adjuvant therapy to be taken. The different prognostic factors for para-aortic lymph nodes metastasis are histological grade and size of the tumour, myometrial wall invasion and lymphovascular dissemination, as well as positive pelvic lymph nodes. However, these elements are not correctly evaluated before and during the surgery. Positive para-aortic lymph nodes can be found without a lymphatic spread to the pelvic area. Even though the prevalence of para-aortic node involvement is weak, it seems legitimate to propose in selected cases of important lymph node involvement, it's complete dissection if a pelvic lymphadenectomy is indicated and if it is surgically possible.

Role of the integrated FDG PET/CT in the surgical management of patients with high risk clinical early stage endometrial cancer: detection of pelvic nodal metastases

BACKGROUND

High risk clinical stage I endometrial cancer (grade 2 and deep myometrial invasion, grade 3 and serous and clear-cell carcinoma) had 10-35% of nodal involvement. Surgical staging is considered reasonable in this setting of women, although unnecessary in 70-90%. The purpose of this study was to determine prospectively the diagnostic accuracy of 18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography 18F-FDG PET/CT in the detection of nodal metastases in patients with high risk endometrial cancer.

METHODS

Eleven women with grade 2 and deep myometrial invasion and 26 with grade 3 endometrial cancer underwent 18F-FDG PET/CT, followed by total hysterectomy, bilateral salpingo-oophorectomy and systematic pelvic lymphadenectomy. Histopathological findings served as the reference standard. Diagnostic performance of 18F-FDG PET/CT in nodal disease detection was reported in terms of accuracy value both in a patient-based and a lesion site-based analysis.

RESULTS

Pelvic nodes metastases were found at histopathological analysis in 9 of the 37 patients (24.3%). Patient-based sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 18F-FDG PET/CT for detection of nodal disease were 77.8%, 100.0%, 100.0%, 93.1% and 94.4%, respectively. Nodal lesion site-based sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 18F-FDG PET/CT were 66.7%, 99.4%, 90.9%, 97.2% and 96.8%, respectively.

CONCLUSION

This study shows that 18F-FDG PET/CT is an accurate method for the presurgical evaluation of pelvic nodes metastases. The high negative predictive value may be useful in selecting patients who only may benefit from lymphadenectomy, minimizing operative and surgical complications.

Endometrial cancer state of the science meeting

There is a pressing need to improve our understanding of endometrial cancer (EC) and uterine carcinosarcoma and to develop new treatment strategies to improve outcomes. In recognition of this, a State of the Science meeting on EC was held last November 28 and 29, 2006, in Manchester, United Kingdom. The meeting was cosponsored by the National Cancer Research Institute (UK), the National Cancer Institute (US), and the Gynecological Cancer Intergroup. The objectives of the meeting were as follows: 1. To review current knowledge and understanding of EC and its treatments. 2. To identify key issues for translational research and clinical trials. 3. To identify the most important trials for women with endometrial carcinoma and uterine carcinosarcoma, both those already underway or to be done, for which the Gynecological Cancer Intergroup might facilitate international cooperation.

Should Preoperative Pathology Be Used to Select Patients for Surgical Staging in Endometrial Cancer?

Introduction:

The decision to offer surgical staging in endometrial cancer is often based on preoperative histology and grade from endometrial biopsy or dilatation and curettage. The primary objective of this study was to evaluate the concordance between preoperative and final pathology from a population-based study of endometrial cancer to address whether preoperative biopsy is a reliable determinant in selecting patients for surgical staging.

Methods:

Retrospective cohort study in Ontario, Canada, from 1996 to 2000. The study included all women with a preoperative diagnosis of endometrioid adenocarcinoma on endometrial biopsy or dilatation and curettage, followed by definitive surgery. All other histological types were excluded. Surgical staging rates were compared according to preoperative pathology. Primary outcome measure was the concordance between preoperative and final pathology, expressed as a Spearman correlation coefficient (ρ). A multivariable logistic regression estimated the effects of demographic variables and grade on our outcome measure.

Results:

There were 1804 evaluable cases in this study. For preoperative grades 1, 2, and 3 endometrioid adenocarcinoma, surgical staging rates were 9.1%, 13.7%, and 25.6%, respectively. Concordance rates with final pathology were 73%, 52%, and 53%, respectively. There was only moderate concordance between preoperative and final pathology (ρ = 0.52). There was no significant difference in concordance rates according to age, year, or hospital volume, but lower concordance rates among teaching hospitals.

Conclusion:

Preoperative biopsy has only a moderate ability to predict final pathology in endometrial cancer, and therefore, additional factors should be considered in selecting patients for a surgical staging procedure.

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.

Diagnostic imaging in Merkel cell carcinoma: lessons to learn from 16 cases with correlation of sonography, CT, MRI and PET

OBJECTIVE

The authors report imaging findings in a series of 16 patients with MCC, a rare tumour which is often managed primarily by a dermatologist. To our knowledge, no equivalent series of MCC has been described in the nuclear medicine literature.

MATERIAL AND METHODS

In this IRB-approved retrospective noncomparative case series 16 patients with biopsy-proven Merkel cell carcinoma were included between January 1999 and October 2007. Twenty-nine whole body PET scans (18F-FDG n=24, 18F-FDOPA n=5) in 16 patients were retrospectively reviewed with regard to tracer uptake in six anatomical sites per patient. For 127/144 of FDG-PET evaluated regions and 68/144 of regions depicted by conventional imaging methods, a valid standard of reference could be obtained. A combined standard of reference was applied, which consisted of histopathology (lymphadenectomy or biopsy) or clinical or radiological follow-up for at least 12 months.

RESULTS

the mean FDG uptake over the clinicopatholigical verified FDG avid areas was 4.7 SUV (1.5-9.9 SUV). The region based assessment of diagnostic value, in consideration of the standard of reference, resulted in a sensitivity of 85.7% and a specificity of 96.2% of FDG-PET (n=127) and in a combined sensitivity of 95.5% and a specificity of 89.1% for morphological imaging methods (n=68). Differences between methods did not reach statistical significance (p=1.00, p=0.18).

CONCLUSIONS

FDG-PET is a highly useful whole body staging method of comparable value compared to conventional imaging methods with restricted field of view. The lessons learned from case series are discussed.

Clinical impact of positron emission tomography or positron emission tomography/computed tomography in the posttherapy surveillance of endometrial carcinoma: evaluation of 88 patients

The objective of this study was to evaluate the validity and clinical impact of positron emission tomography (PET) or positron emission tomography/computed tomography (PET/CT) using 18-fluoro-2-deoxy-D-glucose in the posttherapy surveillance of patients with endometrial carcinoma. Eighty-eight patients previously treated for histopathologically diagnosed endometrial adenocarcinoma underwent 99 PET or PET/CT scans at follow-up visits at Asan Medical Center, Seoul, Korea, between 2001 and 2007. The standard of reference for tumor recurrence consisted of histopathologic confirmation or follow-up information at least 6 months after PET or PET/CT. Of the 88 patients, 24 underwent PET (n= 11) and/or PET/CT (n= 14) scans due to suspected disease recurrence. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of PET and/or PET/CT in detecting recurrence in these patients were 100%, 83.3%, 96%, 95%, and 100%, respectively. Especially, PET/CT revealed true-positive findings in three patients with elevated tumor markers but negative CT findings. The remaining 64 patients underwent PET (n= 8) and/or PET/CT (n= 66) as part of routine posttherapy surveillance; these patients were asymptomatic, with no evidence of disease. The sensitivity, specificity, accuracy, PPV, and NPV of PET and/or PET/CT in detecting recurrence in these patients were all 100%. Clinical decisions on treatment were changed in 14 (21.9%) patients by introducing PET or PET/CT into their conventional posttherapy surveillance program. PET and/or PET/CT were highly effective in discriminating true recurrence in patients with suspected recurrence, highly sensitive in detecting recurrence in asymptomatic patients, and had impacts on clinical decisions in a considerable portion of patients.

Uterine tumors: pathophysiologic imaging with 16alpha-[18F]fluoro-17beta-estradiol and 18F fluorodeoxyglucose PET--initial experience

PURPOSE

To clarify prospectively the relationship between estrogen receptor (ER) expression and glucose metabolism by using 16alpha-[(18)F]fluoro-17beta-estradiol (FES) and fluorine 18 ((18)F) fluorodeoxyglucose (FDG) positron emission tomography (PET) in patients with benign and malignant uterine tumors.

MATERIALS AND METHODS

The institutional review board approved this study, and informed consent was obtained from all subjects. FES and FDG PET studies were performed in 38 patients (mean age, 54.1 years +/- 14.0 [standard deviation]) with benign and malignant uterine tumors to compare differences in tracer accumulation. Regional values of tracer uptake were evaluated by using standardized uptake value (SUV), a normalized value corrected by using injection dose and body weight.

RESULTS

Patients with endometrial carcinoma showed significantly greater mean SUV for FDG (9.6 +/- 3.3) than for FES (3.8 +/- 1.8) (P < .005). Patients with endometrial hyperplasia showed significantly higher mean SUV for FES (7.0 +/- 2.9) than for FDG (1.7 +/- 0.3) (P < .05). Patients with leiomyoma showed significantly higher mean SUV for FES (4.2 +/- 2.4) than for FDG (2.2 +/- 1.1) (P < .005), and patients with sarcoma showed opposite tendencies for tracer accumulation. Tracer uptake in patients with endometrial carcinoma was significantly higher for FDG (P < .001) and significantly lower for FES (P < .05) when compared with values in patients with endometrial hyperplasia. On the other hand, patients with sarcoma showed a significantly higher uptake for FDG (P < .005) and a significantly lower uptake for FES (P < .05) compared with patients with leiomyoma.

CONCLUSION

ER expression and glucose metabolism of uterine tumors measured by using PET showed opposite tendencies. PET studies with both FES and FDG could provide pathophysiologic information for the differential diagnosis of uterine tumors.