Lay Summary: Not much is known about PET scans in endometrial cancer. The bladder can interfere with visualizing the uterus.
Restaging is an integral part of treatment for metastatic disease. The issue is whether PET/CT is a SOC restaging modality for endometrial cancer. PET scan is coming into wider use for endometrial cancer, either for diagnosis, staging or restaging. It has been shown that endometrial cancer is generally highly FDG-avid and that it is feasible to detect the primary tumor, as well as regional nodal and distant metastases, with FDG-PET. As with other types of malignancies, FDG-PET is unable to detect small tumor volumes, and the sensitivity of tumor detection by FDG-PET is reduced in poorly controlled hyperglycemia. The intense activity of FDG excreted in the urinary bladder may impair visualization of adjacent FDG-avid disease, such as primary endometrial cancer or locoregional nodal metastases. Bladder irrigation has been suggested as one method of overcoming this potential problem.
NCCN on p. ENDO-3 says MRI/ CT/PET for initial staging , and there is literature that suggests that PET is useful in post-therapy surveillance for localizing suspected recurrences. A study showed that in the detection of recurrence and the evaluation of treatment response, FDG-PET, implemented by CT and/or MRI, performed better (sensitivity 100%, specificity 88.2%, and accuracy 93.3%) than CT and/or MRI (sensitivity 84.6%, specificity 85.7%, and accuracy 85%) and tumor markers, ie, CA125, CA19-9, CEA, and sialyl TN antigen (sensitivity 100%, specificity 70.6%, and accuracy 83.3%). The results of FDG-PET correlated well with the clinical outcome of the patients, with patients having negative PET results tending to show disease-free courses.
A recent review by Must et al concludes: “ we may highlight that in “T” staging of uterine malignancies FDG PET/CT is a secondary technique compared with CECT and MRI. In some series, FDG PET/CT results have matched MRI. The most promising role of metabolic imaging may be its ability to quantitatively predict DFS, OS, and TTR by assessing “N” status with SUVmax, MTV, and TLG.
For endometrial cancer, these techniques could be used to select patients who do not require surgical staging, thus sparing unhelpful lymphadenectomies. There is an important limitation regarding the staging of very small lymph nodes (<0.5 cm). FDG PET/CT is generally superior to CECT and MRI for detecting distant metastasis in advanced stage patients. PET/CT is recommended for detecting distal metastases in current clinical practice guidelines.4,5 PET/CT may change the management in a significant percentage of patients regarding recurrence monitoring and follow up, resolving uncertain findings of CECT and MRI. In addition, there is growing interest in PET and MRI fusion imaging for the evaluation and follow-up of uterine and cervical cancers“.
Chung HH, Kang WJ, Kim JW, et al. The clinical impact of [(18)F]FDG PET/CT for the management of recurrent endometrial cancer: correlation with clinical and histological findings. European Journal of Nuclear Medicine & Molecular Imaging 2008; 35(6):1081-1088.
ACR Appropriateness Criteria ® 8 Endometrial Cancer of the Uterus 2010
Kitajima K, Murakami K, Yamasaki E, et al. Performance of FDGPET/ CT in the diagnosis of recurrent endometrial cancer. Annals of Nuclear Medicine 2008; 22(2):103-109.
Park JY, Kim EN, Kim DY, et al. Clinical impact of positron emission tomography or positron emission tomography/computed tomography in the posttherapy surveillance of endometrial carcinoma: evaluation of 88 patients. International Journal of Gynecological Cancer 2008; 18(6):1332-1338.
Koyama K, Okamura T, Kawabe J, et al. Evaluation of 18F-FDG PET with bladder irrigation in patients with uterine and ovarian tumors. J Nucl Med. 2003;44:353-358
Alessandra Musto et al, Role of 18F-FDG PET/CT in the Carcinoma of the Uterus: A Review of Literature. Yonsei Med J. 2014 Nov 1; 55(6): 1467–1472.
Kitajima K1, Murakami K, Kaji Y, Sakamoto S, Sugimura K.
Established, emerging and future applications of FDG-PET/CT in the uterine cancer. Clin Radiol. 2011 Apr;66(4):297-307