Role of PET/CT in Gynecological Tumors Based on the Revised FIGO Staging Classification

Novel Treatment of Small-Cell Neuroendocrine of the Vagina

BACKGROUND

Primary vaginal small-cell neuroendocrine carcinoma is an extremely rare and highly aggressive malignancy. Eighty-five percent of patients die within one year of diagnosis from metastatic disease despite multimodal therapy. Gene expression profiling of tumor tissue may be useful for treatment options for various malignancies.

CASE

A 34-year-old nulliparous woman was diagnosed with primary vaginal small-cell neuroendocrine carcinoma. Twenty weeks after the initial visit, she was diagnosed with recurrence and started on chemoradiation based on the results of gene expression profile of tumor tissue. She died 34 months after the initial visit and had a 14-month progression-free survival (PFS).

CONCLUSION

Gene expression profile of tumor tissue in the management of primary vaginal small-cell neuroendocrine carcinoma may be helpful in extending progression-free survival.

High Diagnostic Value of 18F-FDG PET/CT in Endometrial Cancer: Systematic Review and Meta-Analysis of the Literature

The aim of this study was to evaluate the diagnostic performance of (18)F-FDG PET/CT for the preoperative assessment of lymph node metastases (LNM) in endometrial cancer patients and for the assessment of endometrial cancer recurrence (ECR) after primary surgical treatment.

METHODS

A comprehensive search was performed on Pubmed/MEDLINE databases for studies reporting the diagnostic performance of (18)F-FDG PET/CT for assessment of LNM and ECR published up to August 15, 2015. Twenty-one studies (13 for LNM and 8 for ECR) were included in the systematic review and meta-analysis. Pooled estimates of sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of the (18)F-FDG PET/CT were calculated along with 95% confidence intervals (CIs). A summary receiver-operating-characteristics curve (SROC) was constructed, and the area under the SROC curve (AUC) was determined along with Q* index.

RESULTS

The overall pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and AUC (with 95% CI) of (18)F-FDG PET/CT for detection of LNM were 0.72 (95% CI, 0.63-0.80), 0.94 (95% CI, 0.93-0.96), 10.9 (95% CI, 7.9-15.1), 0.36 (95% CI, 0.27-0.48), 39.7 (95% CI, 21.4-73.6), and 0.94 (95% CI, 0.85-0.99), respectively, whereas the corresponding numbers for detection of ECR were 0.95 (95% CI, 0.91-0.98), 0.91 (95% CI, 0.86-0.94), 8.8 (95% CI, 6.0-12.7), 0.08 (95% CI, 0.05-0.15), 171.7 (95% CI, 67.9-434.3), and 0.97 (95% CI, 0.95-0.98), respectively. The overall diagnostic accuracy (Q* index) in LNM and ECR were 0.88 and 0.93, respectively.

CONCLUSION

(18)F-FDG PET/CT has an excellent diagnostic performance for detecting LNM preoperatively and disease recurrence postoperatively in endometrial cancer patients.

Usefulness of 11C-choline positron emission tomography for genital chlamydial infection assessment in a BALB/c murine model

PURPOSE

The aim of this study is to explore the feasibility of 11C-Choline PET in the assessment of the degree of inflammation in the Chlamydia muridarum genital infection model.

PROCEDURES

Forty female Balb/c mice received 2.5 mg of medroxyprogesterone acetate i.m. 9 and 2 days prior to the infection: 21 mice were infected by C. muridarum into the vaginal vault, 12 mice were treated with inactivated chlamydiae, and 7 mice were SPG buffer-treated as negative controls. Three healthy control mice were not treated with progesterone. Mice in each category were randomly subdivided in two groups: (1) sacrificed at 5, 10, 15, and 20 days for histological analysis and (2) undergoing 11C-Choline PET at days 5, 10, and 20 post-infection (20 MBq of 11C-Choline, uptake time of 10 min, acquisition through a small-animal PET tomograph for 15 min).

RESULTS

Infected animals showed a significantly higher standardized uptake value than both controls and animals inoculated with heat-inactivated chlamydiae in each PET scan (P<0.05). All organs of the infected animals had scores of inflammation ranging between 2 and 3 at day 5, decreasing to 1-2 at day 20.

CONCLUSIONS

This preliminary result demonstrated that 11C-Choline PET can highlight a specific proliferation mechanism of inflammatory cells induced by C. muridarum, thanks to a very high sensitivity in detecting very small amounts of tracer in inflammatory cells.

The current status of positron emission mammography in breast cancer diagnosis

Mammography is currently the standard breast cancer screening procedure, even though it is constrained by low specificity in the detection of malignancy and low sensitivity in women with dense breast tissue. Modern imaging modalities, such as magnetic resonance imaging (MRI), have been developed in an effort to replace or complement mammography, because the early detection of breast cancer is critical for efficient treatment and long-term survival of patients. Nuclear medicine imaging technology has been introduced in the field of oncology with the development of positron emission tomography (PET), positron emission tomography/computed tomography (PET/CT) and, ultimately, positron emission mammography (PEM). PET offers the advantage of precise diagnosis, by measuring metabolism with the use of a radiotracer and identifying changes at the cellular level. PET/CT imaging allows for a more accurate assessment by merging the anatomic localization to the functional image. However, both techniques have not yet been established as diagnostic tools in early breast cancer detection, primarily because of low sensitivity, especially for sub-centimeter and low-grade tumors. PEM, a breast-specific device with increased spatial resolution, has been developed in order to overcome these limitations. It has demonstrated higher detectability than PET/CT and comparable or better sensitivity than MRI. The ability to target the lesions visible in PEM with PEM-guided breast biopsy systems adds to its usability in the early diagnosis of breast cancer. The results from recent studies summarized in this review indicate that PEM may prove to be a useful first-line diagnostic tool, although further evaluation and improvement are required.