JNM: PET sensitivity increases with paraaortic lymph node metastasis
The diagnostic performance of PET or PET/CT for the assessment of paraaortic lymph node (PALN) metastasis is acceptable only when it is performed in the population with a greater than 15 percent prevalence of PALN metastasis, according to an article published on Feb. 11 in the Journal of Nuclear Medicine.

Sokbom Kang, MD from National Cancer Center in Goyang, South Korea and colleagues assessed the diagnostic performance of 18F-FDG PET in detecting PALN metastasis in patients with cervical cancer.

Through a search of MEDLINE and EMBASE (1980 to March 2009), the researchers performed a random-effects meta-analysis, regression meta-analysis and a summary receiver-operating-characteristic curve and analyzed 385 patients.

Although specificity of 18F-FDG PET was consistent--97 percent, sensitivity was low and heterogeneous among the studies--34 percent.

Regression metaanalysis revealed a trend of increasing sensitivity according to an increase in the prevalence of PALN metastasis. Kang and colleagues found that PET performed acceptably only in populations with a relatively high probability of PALN metastasis. In the five studies with prevalence greater than 15 percent, estimated sensitivity and specificity were 73 percent and 93 percent, respectively.

“In the population with a low prevalence such as patients with stage I–II disease or negative prior test results, there is not enough evidence yet to convince clinicians to substitute PET or PET/CT for PALN node dissection. The limitations of PET in assessment of PALN metastasis should be seriously considered in designing future clinical trials for high-risk patients with locally advanced cervical cancer,” concluded Kang and colleagues.