PET–CT vs. CT alone in ovarian cancer recurrence

Left Hemi-Hepatectomy to Resect Metastatic Tumor of Round Ligament of Liver in Patients with Ovarian Cancer

The objective of this study is to investigate the surgical, clinical and pathological outcomes of left hemi-hepatectomy during cytoreductive surgery (CRS) in patients with primary ovarian cancer. The electronic medical charts of patients with primary ovarian cancer who received CRS including left hemi-hepatectomy from 2000 to 2023 were reviewed and retrospectively analyzed. A total of 17 patients underwent left hemi-hepatectomy for resection of a deep peritoneal implant in the round ligament of the liver during primary CRS. Among these 17 patients, hepatic parenchymal invasion was confirmed in 10 patients (58.8%). Tumor distribution of others is as follows: Glisson's capsule, hilum, falciform ligament and gall bladder. Fourteen patients (82.4%) achieved CRS; the remaining three patients had residual tumors less than 1 cm. The median period to subsequent chemotherapy was 21 days (range, 12-35 days). No specific complications related to left hepatectomy were identified such as liver failure or bile leakage. Left hemi-hepatectomy for complete surgical resection of a deep peritoneal implant of the round ligament of the liver is surgically feasible and safe.

Imaging of Peritoneal Metastases in Ovarian Cancer Using MDCT, MRI, and FDG PET/CT: A Systematic Review and Meta-Analysis

This review aims to compare the diagnostic performance of multidetector CT (MDCT), MRI, including diffusion-weighted imaging, and FDG PET/CT in the detection of peritoneal metastases (PMs) in ovarian cancer (OC). A comprehensive search was performed for articles published from 2000 to February 2023. The inclusion criteria were the following: diagnosis/suspicion of PMs in patients with ovarian/fallopian/primary peritoneal cancer; initial staging or suspicion of recurrence; MDCT, MRI and/or FDG PET/CT performed for the detection of PMs; population of at least 10 patients; surgical results, histopathologic analysis, and/or radiologic follow-up, used as reference standard; and per-patient and per-region data and data for calculating sensitivity and specificity reported. In total, 33 studies were assessed, including 487 women with OC and PMs. On a per-patient basis, MRI (p = 0.03) and FDG PET/CT (p < 0.01) had higher sensitivity compared to MDCT. MRI and PET/CT had comparable sensitivities (p = 0.84). On a per-lesion analysis, no differences in sensitivity estimates were noted between MDCT and MRI (p = 0.25), MDCT and FDG PET/CT (p = 0.68), and MRI and FDG PET/CT (p = 0.35). Based on our results, FDG PET/CT and MRI are the preferred imaging modalities for the detection of PMs in OC. However, the value of FDG PET/CT and MRI compared to MDCT needs to be determined. Future research to address the limitations of the existing studies and the need for standardization and to explore the cost-effectiveness of the three imaging modalities is required.

PET/Computed Tomography Transformation of Oncology: Ovarian Cancers

Over the last quarter of a century, fluorine-18-fluorodeoxyglucose (FDG) PET/computed tomography (CT) has revolutionized the diagnostic algorithm of ovarian cancer, impacting on the initial disease evaluation including staging and surgical planning, treatment response assessment and prognostication, to the most important role in detection of recurrent disease. The role of FDG PET/CT is expanding with the adoption of new therapeutic agents. Other non-FDG tracers have been explored with fibroblast activation protein inhibitor being promising. Novel tracers may provide the basis for future theragnostic work. This article will review the evolution and impact of PET/CT in ovarian cancer management.

Imaging Recommendations for Diagnosis, Staging, and Management of Ovarian and Fallopian Tube Cancers

Ovarian malignancy the third most common gynecological malignancy and is the leading cause of death in women. Non-specific clinical presentation delays the diagnosis, and they often present in the advanced stage of disease. No imaging modality is recommended for screening as there is no significant mortality reduction. Ultrasound (USG) is usually the initial modality in suspected ovarian mass. MRI is recommended for the characterization of indeterminate ovarian or adnexal mass on USG. CT abdomen and pelvis with oral and IV contrast is the recommended imaging modality in staging the disease, predicting the resectability and in selecting the patients who would benefit from neoadjuvant chemotherapy. Early ovarian cancers are staged by post-surgical histology and undergo upfront surgery. Advanced disease benefit by neoadjuvant chemotherapy and less morbidity by interval cytoreduction where image-guided biopsy is performed for histological diagnosis. Follow-up recommendations are based on tumor histology. CT/PET CT is recommended for diagnosing recurrence.

A Comparative Study between 18F-FDG PET/CT and Conventional Imaging in the Evaluation of Progressive Disease and Recurrence in Ovarian Carcinoma

The aim of this study is to compare the efficiency of conventional imaging and 18F-FDG PET-CT in detecting progressive disease and recurrences over a period of one year (2018), in the case of ovarian cancer, and also to assess the importance of 18F-FDG PET/CT in changing the course of the treatment for these patients. This study included 29 patients diagnosed in various stages with ovarian carcinoma, most of them of epithelial origin. All patients were evaluated throughout their treatment using 18F-FDG PET/CT and various conventional techniques (computed tomography (CT), magnetic resonance imaging (MRI), abdominal and intravaginal ultrasound, chest X-ray). PET/CT was more useful and effective in our group of patients in detecting progressive disease compared with conventional imaging (37.93% vs. 17.24%) and also in establishing the recurrences (24.14% vs. 6.90%). Moreover, F18-FDG PET-CT led to a therapeutic change in 55.17% of the patients of our group, compared with only 17.24% after conventional imaging. This underlines the crucial aspect of the metabolic changes of tumors that should be assessed alongside the morphological ones, with PET-CT imaging remaining the only viable tool for achieving that at present. PET/CT with 18F-FDG represents one of the most important imaging techniques used in the diagnosis and management of ovarian carcinoma. Our results seem to fall in line with what other authors reported, indicating that 18F-FDG PET-CT is potentially gaining more ground in the management of ovarian carcinoma, by influencing therapeutic strategies and by being able to detect relapse and progression accurately.

To Enhance or Not to Enhance? The Role of Contrast Medium 18F-FDG PET/CT in Recurrent Ovarian Carcinomas

Background and Objectives: ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/X-ray computed tomography (PET/CT) represents the mainstay diagnostic procedure for suspected ovarian cancer (OC) recurrence. PET/CT can be integrated with contrast medium and in various diagnostic settings; however, the effective benefit of this procedure is still debated. We aimed to compare the diagnostic capabilities of low-dose and contrast-enhanced PET/CT (PET/ldCT and PET/ceCT) in patients with suspected ovarian cancer relapse. Materials and Methods: 122 OC patients underwent both PET/ldCT and PET/ceCT. Two groups of nuclear medicine physicians and radiologists scored the findings as positive or negative. Clinical/radiological follow-up was used as ground truth. Sensitivity, specificity, negative/positive predictive value, and accuracy were calculated at the patient and the lesion level. Results: A total of 455 and 474 lesions were identified at PET/ldCT and PET/ceCT, respectively. At the lesion level, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were not significantly different between PET/ldCT and PET/ceCT (98%, 93.3%, 97.4%, 94.9%, and 96.9% for PET/ldCT; 99%, 95.5%, 98.3%, 97%, and 98% for PET/ceCT, p = ns). At the patient level, no significant differences in these parameters were identified (e.g., p = 0.22 and p = 0.35 for accuracy, in the peritoneum and lymph nodes, respectively). Smaller peritoneal/lymph node lesions close to physiological FDG uptake sources were found in the cases of misidentification by PET/ldCT. PET/ceCT prompted a change in clinical management in four cases (3.2%) compared to PET/ldCT. Conclusions: PET/ceCT does not perform better than PET/ldCT but can occasionally clarify doubtful peritoneal findings on PET/ldCT. To avoid unnecessary dose to the patient, PET/ceCT should be excluded in selected cases.

ACR Appropriateness Criteria® Staging and Follow-Up of Ovarian Cancer

In the management of epithelial ovarian cancers, imaging is used for cancer detection and staging, both before and after initial treatment. The decision of whether to pursue initial cytoreductive surgery for ovarian cancer depends in part on accurate staging. Contrast-enhanced CT of the abdomen and pelvis (and chest where indicated) is the current imaging modality of choice for the initial staging evaluation of ovarian cancer. Fluorine-18-2-fluoro-2-deoxy-d-glucose PET/CT and MRI may be appropriate for problem-solving purposes, particularly when lesions are present on CT but considered indeterminate. In patients who achieve remission, clinical suspicion for relapse after treatment prompts imaging evaluation for recurrence. Contrast-enhanced CT is the modality of choice to assess the extent of recurrent disease, and fluorine-18-2-fluoro-2-deoxy-d-glucose PET/CT is also usually appropriate, as small metastatic foci may be identified. If imaging or clinical examination confirms a recurrence, the extent of disease and timing of disease recurrence then determines the choice of treatments, including surgery, chemotherapy, and radiation therapy. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Imaging strategy in recurrent ovarian cancer: a practical review

Ovarian cancer is one of the most aggressive gynaecologic malignancies in women worldwide. The lack of proper screening programs and the characteristic abdominal spreading with minimal clinical symptoms give rise of its high lethality. Most patients show advanced disease at diagnosis and have a poor prognosis. The surveillance of ovarian cancer patients after initial treatment is a challenging question in clinical practice and there is no consensus in literature about the most appropriate follow-up strategy for these women. The role of Imaging has become increasingly important, allowing to properly monitor patients, distinguishing the different relapse patterns, thus guiding the correct management and therapy. In this review, we report and analyze the scientific evidence about the role of the different imaging modalities now available in the follow-up strategy and management of Epithelial Ovarian Cancer patients with recurrent disease.

Diagnostic value of positron emission tomography (PET) and PET/computed tomography in recurrent/metastatic ovarian cancer: A meta-analysis

AIM

The study was conducted to assess and compare the overall diagnostic value of positron emission tomography (PET) alone and PET/computed tomography (CT) for the detection of recurrent/metastatic ovarian cancer.

METHODS

A systematic literature search in PubMed, EMBASE and Chinese literature databases (CNKI, VIP and Wanfang) up to August 2014 was performed to identify relevant articles. The diagnostic performance of PET alone or PET/CT was assessed in terms of the following evaluation indexes: summary sensitivity, specificity, positive and negative likelihood ratio, diagnostic odds ratio and area under the curve summary receiver operating characteristics.

RESULTS

Sixty-four studies with 3722 patients were included in this meta-analysis. Favorable results were obtained for both PET/CT and PET alone with similar sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratio and area under the curve in diagnosing recurrent/metastatic ovarian cancer (P > 0.05). However, the sensitivity of PET/CT was significantly higher than PET alone in European patients.

CONCLUSIONS

Both PET and PET/CT have promising diagnostic value in recurrent/metastatic ovarian cancer. The diagnostic performance of PET/CT may be superior to PET alone in European patients.

FDG PET-CT of gynecologic cancers: pearls and pitfalls

FDG PET-CT plays an important role in treatment planning and in prognosis assessment of gynecologic cancer patients. Detection of hypermetabolic tissue with FDG PET, when combined with the high spatial resolution of CT, results in improved cancer detection and localization not afforded by either modality independently. This article is a primer for a radiologist performing PET-CT on gynecologic cancer patients and includes the imaging protocol, normal pattern of FDG distribution in the female pelvis and the lymph node drainage pathways from the gynecologic organs. Clinically relevant imaging findings that should be included in the report are discussed. Case examples illustrate how potential errors in exam interpretation can be avoided by concurrently performing a high-quality diagnostic CT with the FDG PET scan and by analyzing both the stand-alone and the fusion images.

Hypermetabolic Calcified Lymph Nodes on 18Fludeoxyglucose-Positron Emission Tomography/Computed Tomography in a Case of Treated Ovarian Cancer Recurrence: Residual Disease or Benign Formation?

The contribution of positron emission tomography/computed tomography (PET/CT) with 18F-fludeoxyglucose (FDG) in evaluating ovarian cancer recurrence even after a prolonged disease-free interval, and in therapy response is well-described. Calcifications observed in CT, although usually attributed to benign conditions, may actually represent active disease. Such an example of calcified formations is psammoma bodies. We present a case of 56-y. o. patient with ovarian cancer relapse at the supraclavicular area 18 years after complete response and disease-free interval. The patient received chemotherapy and underwent 18F-FDG-PET/CT for the evaluation of treatment response. Both CT corrected and uncorrected PET images showed hypermetabolism in the massively calcified lymph nodes in the neck, mediastinum, axilla and abdomen, indicative of active residual 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.

Benefits of fluorine-18 fludeoxyglucose positron emission tomography in secondary cytoreductive surgery for patients with recurrent epithelial ovarian cancer

OBJECTIVE

To investigate the benefits of fluorine-18 fludeoxyglucose positron emission tomography ((18)F-FDG-PET) in patients undergoing secondary cytoreductive surgery (SCRS) for recurrent epithelial ovarian cancer.

METHODS

Patients were identified, and their clinical information was extracted by review of the gynaecologic oncology database of Peking Union Medical College Hospital. (18)F-FDG-PET scan and analysis were performed by nuclear medicine experts at our hospital.

RESULTS

The PET group and the control group of patients evaluated by conventional imaging methods differed significantly with respect to the proportion of patients who underwent complete SCRS and the number of residual lesions (p = 0.002 and 0.006, respectively). A Cox model showed that longer progression-free survival (PFS) correlated significantly with (18)F-FDG-PET evaluation [relative risk (RR) = 0.432; p = 0.001], sensitivity to platinum-based chemotherapies (RR = 0.604; p = 0.034) and resection completeness (RR = 0.679; p = 0.039). Longer overall survival (OS) correlated significantly with sensitivity to platinum-based chemotherapy (RR = 0.317; p = 0.000) and the CA-125 level after two cycles of chemotherapy (RR = 2.663; p = 0.003). Surgical safety and complications did not significantly differ between the two groups of patients.

CONCLUSION

(18)F-FDG-PET is useful for evaluating patients with recurrent epithelial ovarian carcinoma. Patients who undergo PET-guided SCRS have a greater chance of complete tumour resection and a longer PFS.

ADVANCES IN KNOWLEDGE

SCRS guided by PET results in fewer residual lesions. PET-guided SCRS is safe and can prolong PFS and OS in patients with recurrent ovarian cancer.

Evaluation of gynecologic cancer with MR imaging, 18F-FDG PET/CT, and PET/MR imaging

MR imaging and (18)F-FDG PET/CT play central and complementary roles in the care of patients with gynecologic cancer. Because treatment often requires combinations of surgery, radiotherapy, and chemotherapy, imaging is central to triage and to determining prognosis. This article reviews the use of the 2 imaging modalities in the initial evaluation of 3 common cancers: uterine cervical, uterine endometrial, and epithelial ovarian. Imaging features that affect management are highlighted, as well as the relative strengths and weaknesses of the 2 modalities. Use of imaging after initial therapy to assess for recurrence and to plan salvage therapy is described. Newer functional and molecular techniques in MR imaging and PET are evaluated. Finally, we describe our initial experience with PET/MR imaging, an emerging technology that may prove to be a mainstay in personalized gynecologic cancer care.

The special role of ultrasound for screening, staging and surveillance of malignant ovarian tumors: distinction from other methods of diagnostic imaging

Ovarian cancer is the most aggressive gynecologic malignancy, with a 5-year survival rate ranging around 40%. A crucial factor influencing the prognosis is early detection of a suspicious mass and referral to a gynecologic oncology center for further diagnosis, staging and debulking surgery. Here, we present the different imaging methods ultrasound (US), magnetic resonance imaging, computer tomography (CT) and 18F-fluoro-deoxyglucose positron emission tomography (PET)/CT that are used for the characterization, diagnosis, staging and surveillance of ovarian cancer. In this review, we focus on US and discuss in detail the advantages and the limitations, as well as the appropriate indications for each of the individual imaging techniques.

Impact of FDG PET in optimizing patient selection for cytoreductive surgery in recurrent ovarian cancer

PURPOSE

To investigate the impact of PET and PET/CT scanning on decision-making in management planning and to identify the optimal setting for selecting candidates for surgery in suspicious recurrent ovarian cancer.

METHODS

A retrospective chart review was performed in patients with possible recurrent ovarian cancer after primary optimal cytoreduction and taxane/carboplatin chemotherapy who had undergone FDG PET or FDG PET/CT scans from July 2002 to August 2008 to help make treatment decisions. The analysis included 44 patients who had undergone a total of 89 PET scans. The positive PET scans were classified as follows. (1) localized (one or two localized sites of FDG uptake), (2) multiple (three or more sites of FDG uptake), (3) diffuse (extensive low-grade activity outlining serosal and peritoneal surfaces).

RESULTS

Of the 89 PET scans, 52 (58.4%) led to a change in management plan. The total number of patients in whom cytoreductive surgery was selected as the treatment of choice increased from 12 to 35. Miliary disseminated disease, which was not detected by PET scan, was found in 22.2% of those receiving surgery. Miliary disseminated disease was detected in 6 of the 12 patients with recurrent disease whose treatment-free interval (TFI) was <12 months, whereas none of those with a TFI of ≥12 months had such disease (P = 0.0031).

CONCLUSION

PET or PET/CT is useful for selecting candidates for cytoreductive surgery among patients with recurrent ovarian cancer. To avoid surgical attempts in those with miliary dissemination, patients with a TFI of ≥12 months are the best candidates for cytoreductive surgery.

Challenges of pelvic imaging in obese women

Obesity is a major global health concern affecting all ages, socioeconomic groups, and countries. Although men have higher rates of overweight, women have higher rates of obesity. In the United States, more than 60% of women are overweight or obese, with slightly more than one-third considered frankly obese. Obesity is a major risk factor for noncommunicable diseases such as diabetes mellitus, cardiovascular disease, hypertension, stroke, and specific cancers. Obesity is associated with increased mortality for all cancers, with the highest death rates occurring in the heaviest women. Obesity can contribute to missed diagnoses, nondiagnostic results of imaging studies, imaging examination cancellation because of weight or girth restrictions, scheduling of inappropriate examinations, and increased radiation dose exposure. The utility of the clinical examination is often limited in the obese woman, which results in an even greater reliance on imaging; however, the obese woman may experience a lowered quality of and less access to medical imaging. Recognition of equipment limitations, imaging artifacts, optimization techniques, and appropriateness of modality choices is critical to providing good patient care to this health-challenged group. The clinical indication, the patient's weight, and the body diameters are three key factors to consider when choosing the most appropriate examination. Familiarity with the optimization of imaging techniques across all modalities is important to convert potentially suboptimal examinations into diagnostic-quality studies. The aim of this review is to identify key areas in which obesity affects the imaging care of women with pelvic conditions and to outline strategies to address these areas.

Blind spots at oncological CT: lessons learned from PET/CT

Improved accuracy in oncological computed tomography (CT) could lead to a decrease in morbidity and improved survival for oncology patients. Visualization of metabolic activity using the glucose analogue [¹⁸F]fluorodeoxyglucose (FDG) in combination with the high anatomic resolution of CT in an integrated positron emission tomography (PET)/CT examination has the highest sensitivity and specificity for the detection of primary and metastatic lesions. However, PET/CT costs are high and patient access is limited; thus CT remains the primary imaging modality in oncology patients. We have noted that subtle lesions are more easily detected on CT by radiologists with PET/CT experience. We aimed to provide a brief review of the literature with comparisons of multi-detector computed tomography (MDCT) and PET/CT in primary and metastatic disease with an emphasis on findings that may be overlooked on MDCT in cancer of the breast, lung, colon, and ovaries, and in melanoma, as well as thrombosis in oncology patients. We further reviewed our experience for illustrative comparisons of PET/CT and MDCT studies. Experience in interpreting conventional CT scans alongside PET/CT can help the reader develop an appreciation for the subtle appearance of some lesions on CT that might otherwise be missed. This could improve detection rates, reduce errors, and improve patient management.

Impact of FDG-PET and -PET/CT imaging in the clinical decision-making of ovarian carcinoma: an evidence-based approach

The most definitive role of fluorodeoxyglucose (FDG)-PET/computed tomography (CT) at present is surveillance and detecting recurrence in patients who have completed primary therapy but demonstrate a rising serum tumor marker (e.g., CA-125 levels). In this scenario, PET/CT demonstrates high sensitivity and accuracy in detecting lesions that are otherwise challenging, and appears superior (with less interobserver variability) compared with CT alone. Despite the fact that peritoneal deposits may be missed by PET/CT, the overall performance is better than CT alone. FDG-PET does not play a significant additional role in the primary diagnosis of ovarian cancers; however, the role of combined PET/CT modality has recently begun to be re-explored for initial disease staging, particularly because PET/CT can pick up small unsuspected lesions and thereby provide a better disease assessment of the whole body in a single examination. The baseline PET/CT also subserves an important role for future monitoring of therapy response. Therapy monitoring by PET could help to optimize neoadjuvant therapy protocols and to avoid ineffective therapy in nonresponders early in its course, although PET/CT has cost-effectiveness issues that need further evaluation. The prognostic value of FDG-PET/CT has been investigated in the following areas: in the preoperative setting to predict optimal cytoreduction; to assess the value of a positive FDG-PET following primary surgery; and when employed as a replacement for second-look laparotomy following completion of primary surgery and chemotherapy. The data, although promising, are still sparse in all the three domains for a definite recommendation.

Low-dose non-enhanced CT versus full-dose contrast-enhanced CT in integrated PET/CT scans for diagnosing ovarian cancer recurrence

OBJECTIVE

To evaluate low-dose non-enhanced CT (ldCT) and full-dose contrast-enhanced CT (ceCT) in integrated 18F-fluorodeoxyglucose (FDG)-PET/CT studies for restaging of ovarian cancer.

MATERIALS AND METHODS

One hundred and twenty women who had undergone treatment for ovarian cancer underwent a conventional PET/CT scans with ldCT, and then ceCT. Two observers interpreted and decided in consensus on the PET/ldCT and PET/ceCT images by a 3-point scale (N: negative, E: equivocal, P: positive) per patient and lesion site. Final diagnoses were obtained by histopathological examinations, or clinical follow-up for at least 6 months.

RESULTS

Patient-based analysis showed that the sensitivity, specificity, and accuracy of PET/ceCT was 86.9% (40/46), 95.9% (71/74), and 92.5% (111/120), respectively, whereas those of PET/ldCT were 78.3% (36/46), 95.0% (70/74), and 88.3% (106/120), respectively. All sensitivity, specificity, and accuracy significantly differed between two methods (McNemar test, p<0.0005, p=0.023, and p<0.0001, respectively). The scales of detecting 104 recurrent lesion sites were N:14, E:6, P:84 for PET/ceCT, and N:15, E:17, P:72 for PET/ldCT, respectively. Eleven equivocal and one negative regions by PET/ldCT were correctly interpreted as positive by PET/ceCT.

CONCLUSION

PET/ceCT is a more accurate imaging modality with higher confidence for assessing ovarian cancer recurrence than PET/ldCT.

The role of FDG-PET/CT in gynaecological cancers

There is now a growing body of evidence supporting the use of fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in gynaecological malignancies. Although this molecular imaging technique is becoming increasingly available, PET/CT remains an expensive imaging tool. It is essential to be familiar with the circumstances in which FDG-PET/CT can add value and contribute to patient management and indeed to know when it is unlikely to be of benefit. It is also important to understand and recognize the potential pitfalls. FDG-PET/CT has been most widely adopted for staging patients with suspected advanced disease or in suspected recurrence, offering a whole-body imaging approach. However, there is great potential for this technique to act as a predictive biomarker of response to treatment, as well as a prognostic biomarker. In addition, FDG-PET images may now be incorporated into radiotherapy planning in order to refine the delineation of dose according to metabolically active sites of disease. This article reviews the literature that provides the evidence for the use of FDG-PET in gynaecological malignancies, identifies areas of real benefit and future potential, and highlights circumstances where there is limited value.

PET/CT imaging in gynecologic malignancies: a critical overview of its clinical impact and our retrospective single center analysis

Gynecologic cancers represent a major global healthcare problem since they are associated with a significant mortality and morbidity. Over the last decade, considerable efforts have been spent in the development and optimization of novel diagnostic modalities to achieve an early diagnosis, aid in choosing appropriate treatment, improving long term surveillance, with the ultimate goal of increasing survival of gynecologic cancer patients. A growing body of evidence defines PET/CT as one of the most powerful tools for tumor, nodal and metastasis (TNM) cancer staging both in pre-treatment and in post treatment follow-up settings. At any phase of cancer evaluation, detection of metastasis represents one of the most critical impediments to the cure of tumor; traditional diagnostic imaging modalities, such as computed tomography (CT), are frequently found to inadequately stage the tumor, based on subsequent outcomes. As a consequence, patients may undergo pointless surgery for disease that could be treated with local medical therapies. In the setting of restaging, the ability to describe primary lesion, lymph nodes, possible metastases to peritoneum, bone, liver, lungs and brain renders PET/CT a potential alternative for a series of tests, including bone scanning, MRI or ultrasound, diagnostic CT, lymph node surgical sampling, that need to be used in combination in order to obtain a level of clinical confidence. In this review, we describe, the theoretical advantage and prognostic implications of PET/CT in the management of gynecologic cancer patients.

¹⁸F-Fluorodeoxyglucose positron emission tomography/computed tomography finds answers in cancer patients with increasing tumor markers and negative or equivocal conventional imaging modalities

BACKGROUND

The increase in tumor markers with negative or equivocal conventional imaging modalities represents a serious dilemma in the follow-up of previously treated cancer patients. Positron emission tomography/computed tomography (PET/CT) has emerged as a useful tool in oncological imaging in staging and restaging of most cancers.

OBJECTIVE

This study explored the potential role of ¹⁸F-fluorodeoxyglucose (FDG) PET/CT in the detection and localization of tumor recurrence in cancer patients with increasing serum tumor markers and negative or equivocal conventional imaging modalities.

MATERIALS AND METHODS

This prospective study was conducted on 105 previously diagnosed and treated cancer patients with different pathologies. All patients were referred for ¹⁸F-FDG PET/CT scans because of increasing tumor markers with negative or equivocal conventional imaging modalities. All patients underwent whole-body ¹⁸F-FDG PET/CT scans. The findings were confirmed by clinical and/or radiological follow-up of at least 12 months and histopathologically whenever possible.

RESULTS

PET/CT detected recurrence and/or metastases in 90 patients (85.7%), including 17 recurrences, 50 metastases, and 23 recurrences and metastases. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of PET/CT scans were 95.7, 100, 100, 73.3, and 96.2%, respectively. These parameters were 95, 100, 100, 69, and 95% for PET scans alone and were 91.5, 100, 100, 57.9, and 92.3% for CT scans alone.

CONCLUSION

¹⁸F-FDG PET/CT is a powerful diagnostic tool in restaging of cancer patients. In most cases, PET/CT provides accurate results and helps resolve the clinical dilemma encountered in oncological patients with increasing serum tumor markers and negative or equivocal findings in conventional imaging modalities.

Visualization and quantification of intraperitoneal tumors by in vivo computed tomography using negative contrast enhancement strategy in a mouse model of ovarian cancer

Small animal computed tomography (CT) has poor intrinsic soft tissue contrast, limiting evaluation of intra-abdominal structures. Using standard intravascular-extracellular intravenous contrast (IE-IV) alone is theoretically limited by long acquisition times of traditional small animal scanners that may result in equilibration. We assessed whether a negative contrast strategy of enhancing normal tissue surrounding tumor, instead of the tumor itself, can visualize and quantify intraperitoneal (IP) cancer in a mouse model. Two and a half weeks after IP injection of Hey A8 cells, four groups of three animals each were administered serial dilutions of IV Fenestra LC (RES-IV), oral Gastroview, and IP Optiray 320. Another group of three animals was administered IV Optiray 320 (IE-IV), oral Gastroview, and IP Optiray 320 in successive combinations. Both groups were imaged by CT. Tumor and organ Hounsfield units were measured, and visualization was assessed. With increasing contrast amount, the Hounsfield unit of organs generally increased, whereas that of tumor remained essentially stable. The visualization of abdominal organs and tumor also generally increased with increasing contrast amount. Visualization of tumor and its margins adjacent to liver, spleen, and stomach was significantly better on administering RES-IV. However, for tumor adjacent to bladder, both IE-IV and RES-IV were equivalent. In vivo CT-derived tumor weights correlated highly with ex vivo tumor weights (r = 0.96, P < .0001, n = 15). Thus, CT using negative contrast enhancement strategy allows visualization and quantification of IP tumors. Such a strategy will also enable anatomic localization of functional signal for combination/molecular imaging.

Evaluation of an intraperitoneal ovarian cancer syngeneic mouse model using 18F-FDG MicroPET imaging

OBJECTIVES

The objective of this study was to evaluate the syngeneic immunocompetent mouse model by using the micro-positron emission tomography with 2-[fluorine-18]-fluoro-2-deoxy-d-glucose (F-FDG microPET) imaging of ovarian tumor growth.

METHODS

ID8 ovarian carcinoma cells derived from C57BL/6 mice were intraperitoneally injected into female C57BL/6 mice. Mice were injected with F-FDG (7.4 MBq, intravenous injection), and microPET images were obtained 40 minutes later. Micro-computed tomographic images were also obtained immediately after microPET images for anatomical reference. F-FDG microPET images were acquired at baseline and at 4, 8, 10, and 11 weeks after tumor cell injection. The maximum standardized uptake value (SUVmax) in each time point was obtained from the images and compared to follow the tumor growth.

RESULTS

Physiological uptake of F-FDG was intensely found in the bladder and heart and frequently in the gastrointestinal tract. Diffused uptake of F-FDG was observed in the peritoneal cavity of all tumor-bearing mice at 4 weeks, and high focal uptakes were developed in the peritoneal cavity at 8 to 11 weeks. High focal uptakes increased over time, correlating with a progressive increase in the SUVmax of F-FDG. At 11 weeks, the SUVmax value was significantly increased (1.49 ± 0.10 at 11 weeks vs 0.29 ± 0.03 at baseline, P < 0.01). Tumors in the gut and peritoneum were confirmed by anatomical and histopathological examination.

CONCLUSIONS

Our results demonstrate that the peritoneal tumor growth in the syngeneic ovarian cancer model can be detected by the F-FDG microPET imaging.

Present and future of FDG-PET/CT in ovarian cancer

Integrated FDG-PET/CT has been used successfully for the diagnosis, staging, restaging, therapy monitoring and prognostic prediction of ovarian cancer as well as various other malignant tumors. Compared with conventional PET/non-contrast CT images, combined PET/contrast-enhanced CT images with intravenous iodine contrast medium and sufficient radiation dose may contribute to a more accurate diagnosis with higher confidence. In the future, tracers other than FDG and integrated PET/MRI will be realized. We herein review the place and role of FDG-PET/CT in the management of ovarian cancer, discussing its usefulness and limitations in the imaging of these patients.

The utility and cost of routine follow-up procedures in the surveillance of ovarian and primary peritoneal carcinoma: a 16-year institutional review

Background:

The purpose of this study was to evaluate the number of ovarian cancer and primary peritoneal cancer (PPC) progressive disease cases identified via routine follow-up procedures and the corresponding cost throughout a 16-year period at a single medical institution.

Methods:

Previously undiagnosed epithelial ovarian (n=241), PPC (n=23), and concurrent ovarian and uterine (n=24) cancer patients were treated and then followed via CA-125, imaging (e.g., CT scan, chest X-ray), physical examination and vaginal cytology.

Results:

In the group of 287 patients, there were 151 cases of disease progression. Serial imaging detected the highest number of progressive disease cases (66 initial and 45 confirmatory diagnoses), but the cost was rather high ($13 454 per patient recurrence), whereas CA-125 testing (74 initial and 20 corroborative diagnoses) was the least expensive ($3924) per recurrent diagnosis. The total cost of surveillance during the 16-year period was nearly $2 400 000.

Conclusion:

Ultimately, serial imaging and the CA-125 assay detected the highest number of ovarian cancer and PCC progressive disease cases in comparison to physical examination and vaginal cytology, but nevertheless, all of the procedures were conducted at a considerable financial expense.

Clinical utility of positron emission tomography/computed tomography in the evaluation of suspected recurrent ovarian cancer in the setting of normal CA-125 levels

OBJECTIVES

This study was conducted to estimate the accuracy of [18F]-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) as compared with contrast-enhanced CT (CECT) in detecting cancer in patients who have normal cancer antigen (CA)-125 (<35 U/dL) but are suspected of having a recurrent disease based on clinical symptoms.

METHODS

We retrospectively reviewed the records of patients who had undergone primary cytoreductive surgery and subsequently underwent CECT and FDG-PET/CT for suspected recurrence. [18F]-fluorodeoxyglucose positron emission tomography/computed tomography and CECT interpretation to evaluate a recurrent disease was carried out independently by 2 experienced radiologists who were blinded to the final diagnosis for the suspected recurrence. Long-term follow-up imaging (12 months) and biopsy reports were used to assess the true status of the suspected recurrence seen on FDG-PET/CT or CECT. Sensitivity and specificity of all modalities were estimated. McNemar test was used to compare pairs of modalities. All tests were 2-sided, and P < or = 0.05 was considered statistically significant.

RESULTS

Sixty-six patients met the eligibility criteria for inclusion in our analysis. Fifty-eight percent (18/31) and 54% (17/31) of the patients with normal CA-125 levels had evidence of a recurrent disease on FDG-PET/CT and CECT, respectively. Thirty-one percent (6/19) of the patients with no indication of cancer on CECT had evidence of disease on FDG-PET/CT images, which was supported by pathological proof.

CONCLUSION

[18F]-Fluorodeoxyglucose positron emission tomography/computed tomography is capable of detecting ovarian cancer recurrence in symptomatic patients with normal CA-125 levels and, in this setting, has slightly better sensitivity than CECT and can be considered as the frontline modality for all such patients.

The Roles of Fluorodeoxyglucose-PET/Computed Tomography in Ovarian Cancer: Diagnosis, Assessing Response, and Detecting Recurrence

The potential roles of fluorodeoxyglucose positron emission tomography/computed tomography imaging in ovarian cancer include noninvasive characterization of an ovarian mass, staging, and treatment planning. This article assesses these roles for predicting and monitoring response to treatment, restaging, and early diagnosis of recurrence.

Recurrent ovarian cancer: use of contrast-enhanced CT and PET/CT to accurately localize tumor recurrence and to predict patients' survival

PURPOSE

To compare accuracy and interobserver variability in the detection and localization of recurrent ovarian cancer with contrast material-enhanced (CE) computed tomography (CT) and positron emission tomography (PET)/CT and determine whether imaging findings can be used to predict survival.

MATERIALS AND METHODS

Waiving informed consent, the institutional review board approved this HIPAA-compliant, retrospective study of 35 women (median age, 54.4 years) with histopathologically proven recurrent ovarian carcinoma who underwent CE CT and PET/CT before exploratory surgery. All CE CT and PET/CT scans were independently analyzed. Tumor presence, number of lesions, and the size and maximum standardized uptake value (SUV(max)) of the largest lesion were recorded for patient and region. Surgical histopathologic findings constituted the reference standard. Areas under the receiver operating characteristic curves (AUCs), κ statistics, and hazard ratios were calculated.

RESULTS

Readers' AUCs in detection of recurrence for region were 0.85 (95% confidence interval [CI]: 0.81, 0.90) and 0.78 (95% CI: 0.72, 0.83) for CE CT and 0.84 (95% CI: 0.79, 0.89) and 0.74 (95% CI: 0.67, 0.81) for PET/CT (P = .76); 12 patients died. At PET/CT, size, number, and SUV(max) of peritoneal deposits were significantly associated with poor survival for readers 1 and 2 (P ≤ .01and ≤ .05, respectively), as were long- and short-axis diameters, number, and SUV(max) of distant lymph nodes for reader 1 (P ≤ .001). With CE CT, size (reader 1) and number (readers 1 and 3) of peritoneal deposits were significantly associated with poor survival (P ≤ .01), as were long- and short-axis diameters and number of distant lymph nodes for reader 1 (P ≤ .01). Interobserver agreement ranged from fair (patient, κ = 0.30) to moderate (region, κ = 0.55) for CE CT and fair (patient, κ = 0.24) to substantial (region, κ = 0.63) for PET/CT.

CONCLUSION

Preliminary data suggest that CE CT and PET/CT may have similar accuracy in detection of recurrent ovarian cancer. Tumor size, number, and SUV(max) may have potential as prognostic biomarkers for patients with recurrent ovarian cancer.

Ovarian Cancer: The Role of Functional Imaging as an End Point in Clinical Trials

The Gynaecological Cancer InterGroup conducts collaborative trials in gynecologic cancer and also aims to develop standards that can be used to strengthen all aspects of study methodology. There is an urgent need to develop more refined imaging end points that can be used as early treatment response biomarkers in ovarian cancer. Therefore, the Gynaecological Cancer InterGroup commissioned an expert position paper on the role of functional imaging as an end point in clinical trials in ovarian cancer. In this position paper, we state the limitation of current anatomical imaging methods used in clinical trials, highlight the potential of functional imaging, and provide key recommendations on the use of functional imaging as an end point in ovarian cancer clinical trials.

Role of PET/CT in ovarian cancer

OBJECTIVE

The purpose of this article is to review the role of FDG PET/CT in ovarian cancer, which is the leading cause of death among gynecologic cancers.

CONCLUSION

FDG PET/CT can significantly modify the assessment of the extent of primary and recurrent ovarian cancer and, hence, often alters patient management substantially. FDG PET/CT has thus become a critical tool for the preoperative evaluation of women with primary ovarian cancer and for postoperative follow-up assessment for evidence of recurrence in these patients.

MRI, CT, and PET/CT for ovarian cancer detection and adnexal lesion characterization

OBJECTIVE

The purpose of this article is to describe the role of MR, CT, and PET/CT in the detection of ovarian cancer and the evaluation of adnexal lesions.

CONCLUSION

The goal of imaging in ovarian cancer detection is to expeditiously distinguish benign adnexal lesions from those requiring further pathologic evaluation for malignancy. For lesions indeterminate on ultrasound, MRI increases the specificity of imaging evaluation, thus decreasing benign resections. CT is useful in diagnosis and treatment planning of advanced cancer. Although (18)F-FDG-avid ovarian lesions in postmenopausal women are considered suspicious for malignancy, PET/CT is not recommended for primary cancer detection because of high false-positive rates.

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.