David Garner

Sputum Screening by Quantitative Microscopy A Reexamination of a Portion of the National Cancer Institute Cooperative Early Lung Cancer Study

OBJECTIVE To investigate the hypothesis that image cytometry of sputum specimens can detect squamous carcinoma without requiring visually abnormal cells. DESIGN The sensitivity and specificity of image cytometry were evaluated in a case-control study. MATERIAL AND METHODS Seventy-three sputum slides from the Mayo portion of the National Cancer Institute Cooperative Early Lung Cancer Study were restained by a modified Feulgen method. We examined 40 slides from 9 patients in whom squamous carcinoma developed and 33 slides from 11 patients in whom no cancer developed during a follow-up of at least 5 years. Images of normal epithelial nuclei were collected by using an automated image cytometer. Discriminant analysis was used to determine differences in DNA distribution of normal nuclei in sputum specimens from noncancer patients versus normal nuclei in sputum samples from patients in whom carcinoma developed. RESULTS By using features based on DNA distribution, 74% correct classification of nuclei was possible without human review of the material and without the use of visually abnormal nuclei. A receiver operating characteristic curve demonstrated sensitivities and specificities, including 40% sensitivity and 90% specificity. CONCLUSION Although this study was limited to 20-year-old slides and squamous cell carcinoma, automated image cytometry detected a substantial proportion of patients with squamous cell cancer without using visually abnormal nuclei.

Malignancy associated changes in bronchial epithelial cells and clinical application as a biomarker

A total of 74 bronchial brushing specimens, 24 from patients with advanced stage cancer, eight from patients with CIS, 31 from patients with atypical metaplasia and 11 from normal subjects were examined for the existence of malignancy associated changes (MAC). Conventional fiberoptic bronchoscopy and fluorescence endoscopy was carried out on every case. Each case was classified according to the highest grade of abnormality diagnosed by bronchial biopsy of the suspect areas. During the endoscopy examination, a bronchial brushing specimen was obtained from a visually normal area very remote from the abnormal area as possible such as the opposite lung or another lobe. The bronchial brushing specimens were fixed, mounted and stained by a DNA specific method and approximately 1500 images of individual nuclei per case were captured by an automated high resolution image cytometry. For each of these images, more than 100 nuclear features such as size, shape and chromatin spatial organization were calculated. Discriminant function analysis revealed nuclear features which differentiated between normal bronchial cell nuclei from the normal subjects and ostensively normal nuclei (MAC cell nuclei) from the lung cancer patients. The best discrimination was achieved when the frequency of individual cells expressing MAC was 50% or greater. With this threshold, 75% of the patients with invasive cancer and CIS were correctly classified. Fifty percent of those with severe or moderate atypia and 35% with mild atypia were also MAC positive. The frequency of cells expressing MAC also increased as the degree of abnormality of the groups increased. MAC may be a useful criterium to determine biological behavior of the intra-epithelial (pre-invasive) neoplasia.

DNA-cytometry of progressive and regressive cervical intraepithelial neoplasia.

A retrospective analysis was performed on archival cervical smears from a group of 56 women with cervical intraepithelial neoplasia (CIN), who had received follow‐up by cytology only. Automated image cytometry of Feulgen‐stained DNA was used to determine the differences between progressive and regressive lesions. The first group of 30 smears was from women who had developed cancer after initial smears with dysplastic changes (progressive group). The second group of 26 smears with dysplastic changes had shown regression to normal (regressive group). The goal of the study was to determine if differences in cytometric features existed between the progressive and regressive groups. CIN categories I, II and III were represented in both groups, and measurements were pooled across diagnostic categories. Images of up to 700 intermediate cells were obtained from each slide, and cells were scanned exhaustively for the detection of diagnostic cells. Discriminant function analysis was performed for both intermediate and diagnostic cells. The most significant differences between the groups were found for diagnostic cells, with a cell classification accuracy of 82%. Intermediate cells could be classified with 60% accuracy. Cytometric features which afforded the best discrimination were characteristic of the chromatin organization in diagnostic cells (nuclear texture). Slide classification was performed by thresholding the number of cells which exhibited progression associated changes (PAC) in chromatin configuration, with an accuracy of 93 and 73% for diagnostic and intermediate cells, respectively. These results indicate that regardless of the extent of nuclear atypia as reflected in the CIN category, features of chromatin organization can potentially be used to predict the malignant or progressive potential of CIN lesions.

Detection of malignancy associated changes in cervical cell nuclei using feed-forward neural networks

Normal cells in the presence of a precancerous lesion undergo subtle changes of their DNA distribution when observed by visible microscopy. These changes have been termed Malignancy Associated Changes (MACs). Using statistical models such as neural networks and discriminant functions it is possible to design classifiers that can separate these objects from truly normal cells. The correct classification rate using feed‐forward neural networks is compared to linear discriminant analysis when applied to detecting MACs. Classifiers were designed using 53 nuclear features calculated from images for each of 25,360 normal appearing cells taken from 344 slides diagnosed as normal or containing severe dysplasia. A linear discriminant function achieved a correct classification rate of 61.6% on the test data while neural networks scored as high as 72.5% on a cell‐by‐cell basis. The cell classifiers were applied to a library of 93,494 cells from 395 slides, and the results were jackknifed using a single slide feature. The discriminant function achieved a correct classification rate of 67.6% while the neural networks managed as high as 76.2%.

Evaluation of Costs and Benefits of Advances in Cytologic Technology

ISSUES Uterine cervical cytology smears are among the most cost-effective cancer prevention interventions available, but they are not infallible, and new or modified technologies have been and will be proposed to improve diagnostic accuracy. Before these new technologies are accepted, their performance attributes will be carefully studied and defined. Equally important in this era of fiscal constraints are cost/benefit analyses, for which we review certain guidelines. CONSENSUS POSITION In an effort to control rising costs in the health care sector, there has been a strong incentive to move toward a market system, and a variety of forces are acting to drive down expenditures. These same pressures will continue to be brought to bear on the providers of cervical cytology services. It must be emphasized that the technical knowledge required to define cost-effective medical practice lies within the medical profession itself, which must recognize the following: (a) Resources are finite; (b) Elimination of fraud, abuse and waste is not enough to bring health care expenditures down to levels considered acceptable to government and business; (c) The medical profession must take the responsibility to identify the health and economic consequences of the services it provides and make wise recommendations for allocation of resources to optimize health consequences. The analysis of costs and benefits must be viewed from a societal perspective and presented in terms of the marginal impact on current practice. This does not mean that new technologies must reduce cost; on the contrary, improvements in health can be expected to come at a price, but at a price commensurate with value gained in lives saved or in added quality adjusted life years. To be of value, a new technology for cervical cytology must be more effective in preventing cervical carcinoma. Dysplasia is considered a precursor of carcinoma, and detection of dysplasia has been a surrogate for prevention of cervical carcinoma, but dysplasia does not always lead to carcinoma, least of all mild dysplasia, and policy makers ultimately will insist that a favorable change in health outcome be effected by new technology before it is allocated resources. Alternatively, new technologies may lower cost, perhaps by modifying screening or rescreening procedures according to known risk; by improved cytopreparatory techniques that simplify, improve or speed screening; or by monitoring devices that minimize screening error. In each case the performance attributes of the instrument or human instrument process should be evaluated in the intended use environment. ONGOING ISSUES While current cervical cytology methodology is one of the most effective means of cancer prevention, there continues to be development of new techniques to increase the sensitivity and specificity of this test. With present fiscal constraints, these will be subject to stringent cost/benefit analyses in which the medical profession must play a key role. Such analyses can be quite complicated, considering the additional costs or cost savings of clinical follow-up procedures and the reliability of dysplasias detected by cytology as a surrogate for cervical carcinoma in calculating quality of life years saved.

Costs of colposcopy services and their impact on the incidence and mortality rate of cervical cancer in Canada.

Objective Organized cervical cancer screening services consisting of conventional Papanicolaou cervical smears, colposcopy, and related treatment modalities are readily available in all provinces. The purpose of this report was to study the impact of colposcopy usage and costs on cervical cancer incidence and mortality rates in several Canadian provinces. Knowledge of such information is essential before newer technology such as liquid-based cytology and human papillomavirus testing is introduced or replaces the traditional systems used. Materials and Methods The Ministries of Health of five provinces were contacted and asked to furnish information on the number of colposcopic services and fee-for-service costs for these and for cryosurgery, carbon dioxide laser vaporization, loop electrosurgical excisions, and cold-knife conizations for the year 2000. Canadian Cancer Society estimates of incidence and mortality rates for cervical cancer were also obtained. Results All provinces had similar incidence and mortality rates for cervical cancer; however, the number of colposcopic services on a per-capita basis varied substantially, with Manitoba and Ontario having rates that were approximately two or three times higher. Fee-for-service payments for colposcopy were similar in the Provinces studied but unit costs for surgical treatment services were highest in Ontario and British Columbia. Conclusions Although both the incidence and mortality rates for cervical cancer in Canada fell dramatically after the Walton Report in 1976, these rates have plateaued over the past decade despite widespread availability of colposcopy and related ambulatory treatment services. Higher rates of colposcopy usage do not seem to result in lower incidence rates for this disease. Unit costs for colposcopy are similar among the provinces reviewed, but substantial difference exists for certain treatment services. Additional studies are recommended before the widespread introduction or replacement of existing methods with newer, more costly techniques.

Specific Changes of Chromatin Structure in Nuclei of Normal Epithelium Adjacent to Laryngeal Squamous Cell Carcinoma

The aim of this study was to confirm the existence of specific nuclear texture feature alterations of histologically normal epithelial borders nearby invasive laryngeal cancer (NC). Paraffin sections of NC and of chronic inflammations unrelated to cancer (CI) were analysed for nuclear texture and for integrated optical density (IOD‐index) and were compared to normal epithelium of patients without evidence of cancer (NE). Several discriminant functions based on nuclear texture features were trained to separate different subgroups. As the most important result, specific nuclear texture feature shifts were only found in NC with high‐density lymphocytic stroma infiltrate (NC+). Classification of nuclei of NE versus NC+ was correct in 70%. The same classifier was correct in only 58% when nuclei of NE were classified versus CI. We also found lower values of IOD‐Index within the NC+ group when compared to NE (p < 0:001).