A multicentre validation of Metasin: a molecular assay for the intraoperative assessment of sentinel lymph nodes from breast cancer patients

Aims: Treatment strategies for breast cancer continue to evolve. No uniformity exists in the UK for the management of node‐positive breast cancer patients. Most centres continue to use conventional histopathology of sampled sentinel lymph nodes (SLNs), which requires delayed axillary clearance in up to 25% of patients. Some use touch imprint cytology or frozen section for intraoperative testing, although both have inherent sensitivity issues. An intraoperative molecular diagnostic approach helps to overcome some of these limitations. The aim of this study was to assess the clinical effectiveness of Metasin, a molecular method for the intraoperative evaluation of SLNs. Methods and results: RNA from 3296 lymph nodes from 1836 patients undergoing SLN assessment was analysed with Metasin. Alternate slices of tissue were examined in parallel by histology. Cases deemed to be discordant were analysed by protein gel electrophoresis. There was concordance between Metasin and histology in 94.1% of cases, with a sensitivity of 92% [95% confidence interval (CI) 88–94%] and a specificity of 97% (95% CI 95–97%). Positive and negative predictive values were 88% and 98%, respectively. Over half of the discordant cases (4.4%) were ascribed to tissue allocation bias (TAB). Conclusions: Clinical validation of the Metasin assay suggests that it is sufficiently sensitive and specific to make it fit for purpose in the intraoperative setting

Metasin — An Intra-Operative RT-qPCR Assay to Detect Metastatic Breast Cancer in Sentinel Lymph Nodes

Nodal status is one of the most important prognostic factors in breast cancer. Established tests such as touch imprint cytology and frozen sections currently used in the intra-operative setting show variations in sensitivity and specificity. This limitation has led to the development of molecular alternatives, such as GeneSearch, a commercial intra-operative real-time quantitative Polymerase Chain Reaction (RT-qPCR) assay that allows the surgeon to carry out axillary clearance as a one-step process. Since GeneSearch has been discontinued, we have developed the replacement Metasin assay, which targets the breast epithelial cell markers CK19 and mammaglobin mRNA and identifies metastatic disease in sentinel lymph nodes. The optimised assay can be completed within 32 min (6 min for RNA preparation and 26 min instrument run time), making its use feasible in the intraoperative setting. An analysis by Metasin of 154 archived lymph node homogenates previously analysed by both parallel histology and GeneSearch showed concordance for 148 cases. The sensitivity and specificity of Metasin compared with GeneSearch were 95% (CI 83%-99%) and 97% (CI 91%-99%) respectively; compared with histology they were 95% (CI 83%-99%) and 97% (CI 91%-99%), respectively. The sensitivity and specificity of GeneSearch compared with histology were 90% (CI 77%-96%) and 97% (CI 93%-99%) respectively. The positive predictive value of Metasin was 90% and negative predictive value was 98% for both histology and GeneSearch. The positive predictive value of GeneSearch was 92% and the negative predictive value was 97% compared to histology. The discordance rates of Metasin with both GeneSearch and histology were 3.89%. In comparison, the discordance rate of GeneSearch with histology was 4.5%. Metasin's robustness was independently evaluated on 193 samples previously analysed by GeneSearch from the Jules Bordet Institute, where Metasin yielded comparable results

Sexual history: its importance in averting detrimental misdiagnosis and delayed diagnosis

Two cases where the sexual history proved important in reaching the diagnosis are presented. Case 1 concerns a 37-year-old HIV positive homosexual man, who presented with symptoms of rectal pain associated with bleeding. He was unsuccessfully treated for Crohn disease. A subsequent review of his sexual history led to investigations for venereal infections. A final diagnosis of proctitis secondary to lymphogranuloma venereum was made. The patient was successfully treated with doxycycline and spared an unnecessary colectomy. Case 2 concerns a 22-year-old Caucasian woman under investigation for possible lymphoma. However, the doctor carrying out the biopsy experienced a needle stick injury and the ensuing investigations revealed the patient’s HIV positive status and thus the explanation for her hitherto undiagnosed lymphadenopathy. A prior review of her sexual history could have hastened the diagnosis and prevented the need for invasive tests

CT Review of ovarian fibrothecoma

Objectives: The aim of this study was to investigate the CT imaging characteristics of ovarian fibrothecoma which may aid in the differentiation from early stage epithelial tumours. Methods: Comparison of 36 patients (41 lesions) with pathologically proven ovarian fibrothecoma tumours and 36 (52 lesions) serous papillary carcinomas (SPC) lesions. We noted their laterality, size, density, calcifications, Hounsfield units (HU) and introduced a novel HU comparison technique with the psoas muscle or the uterus. Patients’ clinical findings such as ascites, pleural effusion, CA125 levels, and lymphadenopathy findings were also included. Results: Average age was 67.8 and 66 across the fibrothecoma and SPC cohort respectively. Fibrothecoma tumours had diameters ranging from 24 to 207 mm (Median: 94 mm). 80.6% of the fibrothecoma cohort had ascites which was comparable to the 72.2% in the SPC cohort. 70.7% of fibrothecoma tumour favour a purely to predominantly solid structural configuration (p < 0.001). The average HU value for the fibrothecoma solid component was 44 ± 11.7 contrasting the SPC HU value of 66.8 ± 15. The psoas:tumour mass ratio demonstrated a median of 0.7 whereas SPCs shows a median of 1.1 (p < 0.001). Conclusions: Suspicion of ovarian fibrothecoma should be considered through interrogation of their structural density configuration, low psoas to mass HU ratio and a presence of ascites. Advances in knowledge: CT imaging can be a useful tool in diagnosing fibrothecoma tumours and subsequently reducing onco-gynaecological tertiary centre referrals, financial burden and patient operative morbidity and mortality