Followup

A number of approaches are used to detect recurrent disease after initial surgery and chemotherapy for ovarian cancer. These approaches include physical examination, determination of serum CA-125 levels, and imaging. CT, MRI, and PET all have been used to evaluate ovarian cancer recurrence.55

Recurrent ovarian malignancy may manifest as pelvic masses, peritoneal seeding, malignant ascites, and nodal recurrence (Fig. 5-12). Occasionally recurrent disease may present as pleuropulmonary lesions and liver metastasis.95 Pelvic recurrence may involve the vaginal stump, parametria, urinary bladder, and/or bowel adjacent to the surgical bed. Peritoneal seeding presents as nodules on the peritoneal surface, most commonly around the liver or cul-de-sac, and mesenteric infiltration. Unusual manifestations include metastasis in the extrahepatic abdominal solid organs, bone metastasis, and an abdominal wall lesion involving subcutaneous fat or muscle.95 Accurate detection of recurrent ovarian malignancy by imaging facilitates accurate diagnosis and prompt treatment.

CT is the primary imaging modality to prove macroscopic disease recurrence and can spare patients from the invasive restaging of second-look laparotomy.96 Patients treated for ovarian cancer can be followed up with serial CT of the abdomen and pelvis. CT of the chest is generally not indicated, unless no sites of recurrence are

Figure 5-12. A 69-year-old woman with recurrent ovarian cancer after surgery. A and B, Axial T2-weighted MRI images demonstrate a complex cystic mass in the right pelvis with tethering of adjacent bowel loops (arrow). C and D, Unenhanced axial CT images of the thorax also demonstrate new adenopathy (arrows) in the left internal mammary and supradiaphragmatic regions suspicious for metastases. E, Axial unenhanced CT image of the chest in lung window demonstrates a new nodule (arrow) at the right lung base, also suspicious for metastasis.

Figure 5-12. A 69-year-old woman with recurrent ovarian cancer after surgery. A and B, Axial T2-weighted MRI images demonstrate a complex cystic mass in the right pelvis with tethering of adjacent bowel loops (arrow). C and D, Unenhanced axial CT images of the thorax also demonstrate new adenopathy (arrows) in the left internal mammary and supradiaphragmatic regions suspicious for metastases. E, Axial unenhanced CT image of the chest in lung window demonstrates a new nodule (arrow) at the right lung base, also suspicious for metastasis.

Figure 5-13. A 50-year-old woman with recurrent ovarian mullerian carcinoma after surgery. A, Axial T1-weighted unenhanced MRI of the pelvis demonstrates a complex cystic lesion containing moderately T1-hyperintense fluid and multiple mural nodules (arrows) between the bladder and rectum. B, Axial T1-weighted contrast-enhanced MR image of the pelvis demonstrates increased signal in the mural nodules (arrows) compared with the unenhanced images, indicative of the presence of solid enhancing soft tissue.

Figure 5-13. A 50-year-old woman with recurrent ovarian mullerian carcinoma after surgery. A, Axial T1-weighted unenhanced MRI of the pelvis demonstrates a complex cystic lesion containing moderately T1-hyperintense fluid and multiple mural nodules (arrows) between the bladder and rectum. B, Axial T1-weighted contrast-enhanced MR image of the pelvis demonstrates increased signal in the mural nodules (arrows) compared with the unenhanced images, indicative of the presence of solid enhancing soft tissue.

detected on CT in the presence of elevated tumor marker.88,97 Gadolinium-enhanced MRI is also a valuable diagnostic tool in patients with ovarian cancer (Fig. 5-13). An abnormal MRI examination result with a normal CA-125 value is a strong indication of residual or recurrent tumor.98 It has been reported that gadolinium-enhanced spoiled gradient-echo MRI depicts residual tumor in women with treated ovarian cancer, with an accuracy, positive predictive value, and negative predictive value that are comparable to those of laparotomy and superior to those of serum CA-125 values alone.99 However, neither CT nor MRI can confidently exclude microscopic disease.96

Usually patients with the bulk of the tumor burden in the pelvis are selected for secondary cytoreduction. Two types of pelvic recurrence may be present: central recurrence and pelvic sidewall recurrence.22 The size of a pelvic mass is not an indicator of surgical outcome; however, the extension of a mass to the pelvic sidewall is. MRI may be superior to CT in the assessment of pelvic wall extension because of its high soft tissue contrast and multiplanar capability. The presence of a fat plane at least 3 mm thick on imaging between the tumor and pelvic sidewall is considered necessary for resection.22 Pelvic sidewall invasion and large bowel obstruction are significant indicators of tumor nonresectability, although invasion of the bladder and rectum by itself is not a contraindication to definitive surgical therapy (pelvic exen-teration may be considered in select cases). Preoperative imaging is essential in patients considered for potential secondary cytoreductive surgery, so that the presence of tumor elsewhere and any indicators of nonresectability can be identified.22

Multiple standard uptake value comparisons may be helpful for evaluation of tumor response to treatment, although variations in measurement are sometimes attributed to the difference in scanners, scanner dose, and postinjection imaging time. Mixed results have been reported regarding the value of FDG-PET in evaluating recurrent ovarian cancer.54 One preliminary study suggested that in the follow-up of patients with ovarian cancer, FDG-PET could detect recurrence with higher accuracy than CT, and even with higher sensitivity than the tumor marker CA-125, with the additional advantage of being able to localize the site of recurrence.100 However, other studies found that in the diagnosis of recurrent ovarian cancer, FDG-PET had a limited ability to detect small tumors and did not yield higher overall accuracy than Ct.101-103 Nevertheless, FDG-PET/CT has been found to have a higher accuracy in identifying recurrent ovarian tumor nodules that are at least 1 cm in size among patients with biochemical evidence of recurrence and negative or equivocal conventional CT findings, thus facilitating timely surgical cytoreduction.104

The sensitivity of PET is low in patients with clinically occult recurrence of ovarian cancer.105 However, the sensitivity of FDG-PET in detecting recurrent ovarian cancer is higher in patients with clinically suspected relapse than in patients judged clinically disease-free. Therefore, FDG-PET may be useful in patients with clinically suspected recurrence but with negative or equivocal anatomic imaging findings.55,106,107 When combined with clinical parameters such as CA-125 level, the sensitivity of FDG-PET can be as high as 97.8% in detecting recurrent ovarian cancer.108 The combination of FDG-PET and CA-125 titer is therefore useful for an accurate detection of recurrence.

The reported specificity of PET in the detection of recurrent ovarian cancer ranges widely—from 42% up to 100%.101,103,105,106,109,110 Physiologic activity in the abdomen and pelvis is one of the factors that can potentially affect the specificity of PET.55 Physiologic uptake of FDG can be seen in the gastrointestinal tract, liver, and spleen, in addition to the urinary tract, since FDG is excreted by the kidneys. Therefore, digital fusion of PET and CT scan images allows for better differentiation between physiologic and pathologic activity on PET, and for lesions that are truly pathologic, enables accurate localization for treatment planning111 (Fig. 5-14). Although Drieskens and associates93 demonstrated that FDG-PET and CT have relatively low sensitivity for the detection of peritoneal metastases compared with surgical staging, FDG-PET has a higher specificity and may be useful for evaluating residual or recurrent disease after surgery. Overall, it appears that FDG-PET has the advantages of a high positive predictive value in detecting recurrent or residual disease after treatment.102,104

Such mixed results may be partially attributable to the fact that non-neoplastic hypermetabolic lesions are frequently present in post-treatment patients. These lesions include granulomatous disease, abscess, surgical changes, radiation changes, inflammation, and foreign body reaction. Therefore, consultation with the simultaneously obtained CT images, especially contrast-enhanced CT images, may help to reveal the nature of these FDG-avid non-neoplastic processes. It may be prudent to

Figure 5-14. A 29-year-old woman with endometrioid adenocarcinoma arising from an endometriotic cyst, presented with elevated CA-125 after surgery and chemotherapy.

A, Axial unenhanced CT image of the pelvis demonstrates a heterogeneous oval mass (arrow) in the left pelvis. B, Axial FDG-PET image fused with the CT image demonstrates increased metabolic activity in the mass with standardized uptake values of up to 7.7. Subsequent surgical pathology showed adenocarcinoma with clear cell and endometrioid components. (We thank Dr. Pek Lan Khong at the Department of Diagnostic Radiology, University of Hong Kong for providing these images.)

Figure 5-14. A 29-year-old woman with endometrioid adenocarcinoma arising from an endometriotic cyst, presented with elevated CA-125 after surgery and chemotherapy.

A, Axial unenhanced CT image of the pelvis demonstrates a heterogeneous oval mass (arrow) in the left pelvis. B, Axial FDG-PET image fused with the CT image demonstrates increased metabolic activity in the mass with standardized uptake values of up to 7.7. Subsequent surgical pathology showed adenocarcinoma with clear cell and endometrioid components. (We thank Dr. Pek Lan Khong at the Department of Diagnostic Radiology, University of Hong Kong for providing these images.)

wait at least 6 weeks before PET/CT is performed to evaluate the surgical or irradiated bed. Integration of clinical information in the interpretation process may further increase specificity.

Overall FDG-PET has been shown to have a prognostic value similar to that of second-look laparotomy, and can substitute for second-look laparotomy in the follow-up of patients who have had ovarian carcinoma, especially when there is a high risk of recurrence.112 Therefore, FDG-PET can reduce unnecessary invasive staging procedures and save health care costs when used appropriately in the management of patients with recurrent ovarian cancer.113 Furthermore, precise localization of recurrent tumor during surgical treatment is often difficult, owing to limited tumor size and postsurgical anatomic modifications. It has been reported that the use of an FDG-sensitive surgical gamma probe combined with preoperative PET/CT image fusion can help to detect occult metastasis and guide laparoscopic excision in the patient with recurrent ovarian cancer.114

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