F. Sharp

Relation between tissue structure and imposed electrical current flow in cervical neoplasia

BACKGROUND When an electrical potential is applied to human tissue, the pattern of the resulting current flow is determined by the shapes, arrangements, and internal structure of the tissue cells. By measurement of the electrical current patterns over a range of frequencies, and use of an inverse modelling procedure, electrical variables describing the tissue structure can be calculated. We used this method to develop a screening technique for the detection of cervical precancers. METHODS We used a pencil probe (diameter 5 mm) to measure electrical impedance spectra from eight points on the cervix in 124 women with abnormal cervical smears. Variables that should be sensitive to the expected tissue changes were calculated. These were compared with the colposcopic results. FINDINGS The measured electrical impedance changes were those predicted on the basis of the expected tissue structures. Measurements made on normal squamous tissues were well separated from those made on precancerous tissues. We constructed receiver-operating-characteristic curves, comparing measurements made on normal tissue and that showing cervical intraepithelial neoplasia grade 2/3; the area under the curve was 0.951. These groups of women could be separated with a sensitivity of 0.92 and a specificity of 0.92. INTERPRETATION Characteristics of the electrical impedance spectra of tissues can be explained by changes in cell arrangements (layering) and in the size of the nuclei. This relation opens the way to deriving tissue structure from electrical impedance spectral measurements. We show that this approach can be used to give good separation of normal and precancerous cervical tissues.

Anal intraepithelial neoplasia: part of a multifocal disease process

Invasive carcinomas of the anogenital epithelium share a common aetiological factor--human papillomavirus (HPV) type 16. Although genital intraepithelial neoplasia may be multifocal, there have been no studies of the prevalence of anal intraepithelial neoplasia in women with intraepithelial neoplasia of the genital tract. We tested the hypothesis that women with high-grade cervical intraepithelial neoplasia are at higher risk of disease in the anus than are control women of similar age with no history of anogenital neoplasia. 29 (19%) of 152 women with cervical intraepithelial neoplasia grade III had histological evidence of anal intraepithelial neoplasia. Of the 29 patients, 11 had grade III anal lesions; 2 of those women had concomitant invasive anal squamous-cell carcinomas. Only 7% (8/115) women with high-grade lesions of the cervix alone had evidence of anal intraepithelial neoplasia; by contrast, 57% (21/37) of those with more than one focus of intraepithelial neoplasia (cervix plus vulva, vagina, or both) had anal lesions. HPV 16 DNA was identified in 18 (51%) of 35 anal biopsy samples in the study group. No evidence of anal intraepithelial neoplasia was found in the control group (50 women), although 2 patients had grade I cervical lesions. HPV 16 DNA was identified in 12 (24%) of biopsy samples from the cervix and 7 (14%) from the anus in the control group; all 7 women with anal HPV 16 had concomitant cervical infection. The role of anal examination in the assessment of women with any focus of genital intraepithelial neoplasia requires further investigation.

In‐vivo studies of uterine electrosurgery

Objective To study the effects of electrosurgery on the living human uterus.

Anal colposcopy and the diagnosis of anal intraepithelial neoplasia in high-risk gynecologic patients.

The objective of this study was to define the colposcopic features of the normal anal canal and of anal human papillomavirus (HPV)-associated lesions, including anal intraepithelial neoplasia (AIN), and to correlate the colposcopic impression with the final histopathologic diagnosis. A controled colposcopic screening study of women considered at risk for HPV-associated anal epithelial abnormalities was carried out. All colposcopic assessments included a biopsy with matching histopathologic diagnosis. The study group consisted of 213 women who were considered at risk of anal HPV infection and AIN. A further group of 50 women, who had no previous history of ano-genital HPV infection or AIN and whose recent cervical smear was negative were recruited as controls. Informed consent was obtained from all patients, and the study was approved by the local ethical committee. In the control group of 50 women no AIN was detected. Normal histology was obtained in 45/50 (90%) biopsies where normality had been predicted on colposcopy. Histologic diagnosis in the at-risk group was normal in 143 (67%), subclinical papillomarvirus infection (SPI) in 24 (11%), and AIN of all grades (including three cases of early invasive squamous cancer in a field change of AIN III) in 46 (22%) patients. Nineteen of 24 (79%) cases of SPI were incorrectly predicted as normal on colposcopy, and another one (4%) as AIN I–II. Only four (17%) cases of SPI were correctly predicted at colposcopy. Of the 46 cases of histologically proven AIN, 26 (56%) were AIN I–II, and 20 (44%) were AIN III. Some 50% of AIN I–II were incorrectly predicted as SPI on colposcopy. Of the 20 AIN III lesions, 15 (75%) were correctly predicted by colposcopy. Three (20%) of these lesions contained foci of early invasion, of which in only one case (33.3%) was invasive disease suspected at colposcopy. Some 25% (5/20) of AIN III lesions were incorrectly diagnosed as AIN I–II at colposcopy. As is the experience with colposcopic assessment of the cervix, anal colposcopy predictions correlated well with the final histologic diagnosis, at the normal and high-grade AIN ends of the spectrum. The colposcopic predictive distinction between SPI and low-grade AIN (I–II) was less accurate. It was difficult to distinguish early invasive lesions within a field change of AIN III, from pure AIN III. In these studies there were three cases of early anal squamous carcinoma arising in AIN III lesions, two of which were unsuspected clinically.

The management of multiple pregnancy in women with a lower‐segment caesarean scar. Is a repeat caesarean section really the ‘safe’ option?

Summary. Multiple pregnancy occurring in a patient who has previously had a lower‐segment caesarean section is an unusual sequence of events. Retrospective analysis over an 11 ‐year period in Sheffield from 1975 to 1985, revealed 25 cases, a rate of 1 in 3300 deliveries. The caesarean section rate in this group of women rose from 20% (3/15) in the first six years to 70% (7/10) in the latter years for no obvious reason. This change in management did not produce any improvement in fetal outcome but there was an increase in maternal morbidity. This analysis and a review of available literature suggest that multiple pregnancy is not in itself an indication for elective repeat caesarean section.

Conclusions and recommendations from the Helene Harris Memorial Trust Fifth Biennial International Forum on Ovarian Cancer, May 4-7, 1995, Glasgow, UK.

The Fifth Biennial International Forum on Ovarian Cancer was held by the Helene Harris Memorial Trust in Glasgow, UK. The main points of the presentations given by the invited speakers, together with the fruits of extensive discussions are presented here as a series of conclusions and recommendations which should be given consideration by all those having an interest in researching or treating ovarian cancer. The individual points are grouped into topics considering whether there is an identifiable ovarian pro-cancer, whether ovarian cancer is preventable, advances in familial ovarian cancer, its molecular genetics, ways of optimizing treatment, obstacles to successful treatment and approaches to gene therapy.

Endoscopic localization of the squamocolumnar junction before cervical cone biopsy in 284 patients

A preoperative examination of the endocervical canal was performed in 284 patients scheduled for excisional cone biopsy because of abnormal cervical cytology and unsatisfactory colposcopy. The information obtained regarding the depth of the new squamocolumnar junction (SCJ) was used to tailor the length of the cone specimen in an attempt to remove the entire transformation zone (TZ), and was associated with a low rate of incomplete disease excision. An analysis of the data generated by this study indicates that the position of the new SCJ is influenced by age, menopausal status, and the use of estrogen‐containing medication.

Conclusions and recommendations from the Helene Harris Memorial Trust Fourth Biennial International Forum on Ovarian Cancer 11-14 May 1993, Toronto, Canada.

The Helene Harris Memorial Trust organizes biennial international meetings of leading clinicians and scientists to discuss progress in the understanding and treatment of ovarian cancer. The conclusions of this meeting, together with recommendations for future research are published as a guide to others working in this field. The 107 conclusions and recommendations presented cover the full range of current topics in ovarian cancer research including the biology of early and borderline tumors, the relationship of benign to malignant tumors, in vitro models, the role of cytokines, genetic epidemiology, oncogenes and tumor suppressor genes, allele loss, localization of the BRCA1 gene, DNA ploidy in prognosis, the therapeutic use of interferon, platinum and taxoid drugs, screening with panels of tumor antigensm immunotherapy and potenial for gene therapy.