In that paraneoplastic neurologic disorders occur in some people with cancer — including lung, breast or ovarian cancer — and may develop when cancer-fighting antibodies mistakenly attack cells in the nervous system, often the routine non-invasive oncologic evaluations (such as physical examination, mammography in women, prostate specific antigen testing in men, and other assessments) of these patients may neglect to reveal underlying cancers.    Andrew McKeon, from Mayo Clinic (Minnesota, USA), and colleagues, analyzed the medical records of 56 consecutive patients with suspected paraneoplastic neurologic disorders whose standard evaluations  did not reveal cancer.  The researchers conducted joint positron emission tomography (PET) coupled with computed tomography (CT) scanning.  The combined PET-CT technique detected abnormalities suggestive of cancer in 22 of the patients (39%), of whom 10 (18%) had cancer diagnoses confirmed by biopsy or another method. The team also observed four of the 10 detected cancers using PET-CT that were outside the anatomical scope of CT of the chest, abdomen and pelvis.  Noting that: “Combined data from 2 previous studies using conventional PET alone (123 patients) revealed that 28% of patients had a PET abnormality suggestive of cancer and that 12% had a cancer diagnosis,” the team urges that: “PET-CT improves the detection of cancers when other screening test results are negative, particularly in the setting of seropositivity for a neuronal nuclear or cytoplasmic autoantibody marker of cancer.”