Case ReportsLaparoscopic resection of occult metastasis using the combination of FDG-positron emission tomography/computed tomography image fusion with intraoperative probe guidance in a woman with recurrent ovarian cancer
Introduction
Epithelial ovarian cancer is the leading fatal gynecologic malignancy. In 2000, there were about 24,400 new cases of ovarian cancer and 14,500 deaths in the USA [1]. Following primary surgical cytoreduction, the current standard of care for ovarian cancer includes systemic platinum-based chemotherapy. Despite a high response rate to chemotherapy, the 5-year survival rate among women with advanced disease remains low [2]. A number of approaches, including CA125 serum assay, computed tomography (CT), and magnetic resonance imaging (MRI), have been used to detect recurrent disease. Recognized limitations include failure to detect small recurrent lesions [3], [4].
[18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) has been used to detect recurrent ovarian cancer [5], [6]. This technology uses radiolabeled glucose, which is preferentially trapped in tissues with increased glucose consummation such as malignant tumors. FDG-PET has proven useful for detecting early recurrences potentially accessible to secondary surgery [7].
Precise anatomic tumor location can be improved by combining FDG-PET with CT image fusion. This can be achieved by using combined software analysis of images from separate devices, or more recent combined PET/CT devices that offer contemporaneous sequential acquisition and co-registration. However, exact location of occult metastases during secondary surgery is often difficult, owing to small tumor size and treatment-induced anatomic modifications.
The use of surgical gamma probes has become increasingly popular over the past few years, with the development of sentinel node (SN) mapping in gynecologic malignancies [8], [9]. FDG-sensitive probes, which detect differences in radioactivity emitted from tumor-bearing and adjacent normal tissue, can improve the detection and facilitate the resection of occult metastases. Few studies, mostly in colorectal cancer, have tested the combined use of whole-body PET with FDG and intraoperative FDG-sensitive probe for the detection of occult tumors [10], [11], [12].
We describe the first case of laparoscopic resection of occult metastasis based on the combined use of FDG-PET/CT image fusion and intraoperative FDG-sensitive probe guidance in a patient with recurrent ovarian cancer.
Section snippets
Case report
In August 1999, a 62-year-old postmenopausal woman was referred to our gynecology department with a history of metrorrhagia and stress urinary incontinence. Ultrasonography revealed uterine myomas. Vaginal hysterectomy with bilateral salpingo-oophorectomy, sacrospinofixation, and the tension vaginal tape procedure were performed. Final histology revealed a right ovarian serous adenocarcinoma with a peritoneal implant. She then underwent laparoscopic peritoneal washing, para-aortic and bilateral
Discussion
Unresectable recurrent ovarian cancer is uniformly fatal, despite responses to second- or third-line chemotherapy. Early detection of potentially resectable recurrences is based on biological markers and imaging techniques but its impact on survival is controversial [6]. CA125 serum assay is recommended during follow-up of women with ovarian cancer, and an increase of at least 35 U/ml strongly suggests recurrence after initial complete surgery. CA125 serum levels were normal in our patient, as
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Cited by (23)
Normal Variants and Pitfalls Encountered in PET Assessment of Gynecologic Malignancies
2018, PET ClinicsCitation Excerpt :Its use has also expanded owing to its use in the planning of external beam radiation therapy.16–29 There are reports of institutions using FDG PET/CT for surgical planning, especially nodal staging and intraoperative probe guidance for the removal of metastatic implants.30–41 Imaging the area below the diaphragm involves some special considerations, and it is very important to recognize the artifacts, normal variants, and pitfalls, especially for the female pelvis.42,43
Medical image fusion: A survey of the state of the art
2014, Information FusionCitation Excerpt :However, the exact radiation levels are not well understood topics, and CT has several other limitations such as limited tissue characterization because of the nature of X-ray probe, restriction of CT scan to transverse slices and practical limitation on number of X-rays that can be produced in the short scan times. Fusion combinations in which CT is one of the main modalities include MRI–CT–PET–SPECT–DSA–MEG [47,134,161], MRI–CT [15–17,147,171,176,177,258,61,149,184,150,259,170,153,172,169,154–156,186,64,192,157,193,127,158,175,195,141,162,128,91,164,165,196,239,132,173], SPECT–CT [216,221,99,241,233,246,235,213,214,253,215,243,251], MRI–CT–PET [51,188,197–199], CT–FOCAL [179], ultrasound–CT [260,231,234,238], FDG–CT [223,224], nuclear medicine–CT [201], endoscopy–MRI [183], MRI–CT–SPECT [26,202], MRI/CT–PET–SPECT [187], CT/SPET–SRS [242], FDG–PET–CT [261,226,247,249], PET–CT [244,262,211,217,236,29,220,218,68,250,252,248,219,76,255,263,257], TRUS–CT [264], ultrasound–CT [265,240,254], PET–CT–ultrasound [256]. Positron emission tomography, widely known as PET imaging or a PET scan, is a useful type of nuclear medicine imaging.
Intraoperative imaging
2013, Best Practice and Research: Clinical Obstetrics and GynaecologyCitation Excerpt :Intraoperative identification of gynaecological tumours with radical isotope imaging techniques was reported, as far back as 1987, to have high predictive value, reduced recurrence rate and identified tumour regrowth while other methods failed.69 A case report70 described the first ever laparoscopic resection of occult metastasis in woman with recurrent ovarian cancer using a combination of fluorodeoxyglucose for perioperative positron emission tomography and computed tomography (Fig. 8) and intraoperative gamma probe (Fig. 9). The application of this novel approach for intraoperative tumour localisation and verification of tumour excision in recurrent ovarian cancer was later described in three women.71
Imaging of Ovarian Cancer
2010, Early Diagnosis and Treatment of Cancer Series: Ovarian CancerNovel perioperative imaging with <sup>18</sup>F-FDG PET/CT and intraoperative <sup>18</sup>F-FDG detection using a handheld gamma probe in recurrent ovarian cancer
2008, Gynecologic OncologyCitation Excerpt :Extrapolating from the increasing use of hand held gamma probes to detect gamma emission from peritumoral injection of technetium-99 (99Tc) during lymphatic mapping and sentinel lymphadenectomy, we have demonstrated the feasibility of translating preoperative imaging results to the surgeon in real time to assess disease distribution (including the presence or absence of occult disease). The use of a handheld gamma probe to detect tumors concentrating 18F-FDG has been previously shown in many tumor types [12–20]. The 511 keV photons emitted from positron annihilation can be detected with the handheld gamma probes [16,20–22], and are most effectively detected from one to three hours following intravenous injection of 18F-FDG [23].