Colposcopy of Actinic Light

The New Colposcopic Technique in the Prevention of Cervical Cancer

Summary

Cervical cancer is one of the most common tumors in women. An estimated 500,000 cases of invasive cancer are diagnosed worldwide each year. The high incidence reflects the deficiency of early detection programs used.

From 1990 to nowadays a plethora of new diagnostic methods have been tried.

Cervical Intraepithelial Neoplasias CIN) induced by the Human Papilloma Virus (HPV) frequently are not diagnosed by means of the usual techniques. In many medical consulting offices the lack of optimal equipment and of a simple test to diagnose this disease force gynecologists to use laboratory tests that need long waiting time.

The aim of this page is the introduction of a new colposcopic system knows as: actinic light colposcopy that solves the above problems.

The new instrument is specifically for diagnose the Cervical Intraepithelial Neoplasia. In addition, its results are obtained at the same moment that the procedure is performed.

Introduction

The growing incidence of sexually transmitted diseases worldwide due to the human papillomavirus (HPV) is closely related to the increase in cervical intraepithelial neoplasias (CIN) and cervical cancer .

In order to detect and control CIN, the gynecologist must employ laboratory tests which often take long and perhaps increase the patient’s anxiety, in addition to elevating costs.

Since the middle of the last century, the Pap smear test has aided in the prevention of cervical cancer worldwide, but is not as reliable as one would hope .At times it is necessary to use more sophisticated resources like the fluorescence spectroscopy or the polymerase chain reaction with their associated waiting times and elevated costs.

In a medical center, it is not easy to diagnose CIN due to a lack of procedures, equipment and tests that easily facilitate a reliable diagnosis. For this reason, more than 4,000 articles about detection techniques were reviewed.

Is important to report that the design and the construction of this colposcope always respected Hinselmann’s stereoscopic optical principles . Although this new colposcopy has nothing to do with longitudinal bands of actinic radiation, it was named “Actinic Light Colposcopy” to differentiate it from the other colposcopes and likewise ophtalmologists, in order to visualize cornea lesions, use a lamp that is commonly known as “Actinic Light” because it possesses a cobalt filter. It’s a reliable technique, reasonably priced, quick to apply and patients receive results quickly. In this way it is ideal for programs of control of reproductive health as well as for routine use by gynecologists either publically or privately.

Human Papilloma Virus

The viral classification Papilloma belongs to the very extensive Papovaviridae family; they are DNA viruses that infect many species of animals including man. There exist more than 100 types that infect the man, and 30 of them are capable of infecting the lower female genital tract. It is named papilloma because it causes warts.

Interest in this kind of virus has been gradually on the rise since 1970, when for the first time it was found to participate in the etiology of cervical cancer.

Some of the viruses are of the benign type called “low risk” (primarily type 6 and 11) that cause genital warts or condyloma, but there are others that are oncogenic or malignant, known as “high risk” (primarily types 16, 18, 30, 31, 33, 35, 45, 51, 52, 58). The the most common high risk HPV virus in America has been HPV 16 found in up to 50% of the cases HPV is considered to be the most significant risk factor for cervical intraepithelial neoplasias that can be a cause of cervical cancer.

Cervical Cancer

Cervical Cancer is common among women; it is estimated that worldwide there are 500,000 cases a year, 80% in developing countries where close to 200,000 perish. In the United States the incidence of Cervical Cancer is 8 out of every 100,000 women, 4.2:100,000 in Israel, compared with Peru and Mexico where the figures are 54.6 and 50 respectively. Among the causes of mortality due to neoplasias in the Mexican female population, cervical cancer ranks first with 12 to 16 deaths per day; in the year 2000, 4,604 deaths were registered according to the Health Secretary .

Cervical Cancer initiates with changes of the cervical epithelial cells, that gradually become abnormal cells called Koilocytes , that stain differently due to the presence of keratin; its presence is an indicator of HPV infection and is known by the term dysplasia or cervical intraephileal neoplasias .

Advances in science and technology from the past century up until today have permitted a decrease in the epidemiological window, the period between the initial presence of the etiological agent—HPV in this case—and the appearance of the disease. Detailed observations carried out over a long period of time demonstrated that cervical cancer does not appear spontaneously as a lesion of a “novo”, and that the cervix epidermis is a tissue that is constantly undergoing predictable changes both in its state of health as well as as a disease.

There exists three significant advances in the diagnosis of the disease; modification in cytology techniques, diverse molecular biology tests, digitalizing images and the fluorescence spectroscopy . However, the diagnostic method most widely used until now has been the exfoliative cytology (Pap Test) through the staining of Papanicolaou smear testing.

Using the colposcopy to perform the taking of a biopsy continues to be considered as the Criterion Standard or “” .

Colposcopy

The colposcopy was invented in Altona, Germany in 1925 by Dr. Hans Hinselmann who, unsatisfied with the means of exploration then employed and trying to discover the initial forms of the disease, combined a powerful light source with a stereoscopic increase to improve the observation of the cervix.

The instrument that is used to perform a colposcopy, increases the size of the image as a stereoscope microscope while taking advantage of viewing with both eyes thus creating three-dimensional images, through two separate lenses, forming an angle similar to that formed between the axis of our eyes (between 7 and 12 degrees) which gives two different images, one for each eye, and the perception of three-dimensions.

Technique and colposcopic procedure

The colposcopic technique consists in the insertion of a vaginal specula with the patient in the correct gynelcological position and placing the colposcope a few centimeters (from 20 to 40 centimeters) from the vaginal introito through which the instrument never touches the woman. Carefully focusing the device, an observation of the tissue of the lower female genital tract, its morphology and its vascular patterns are made using the acetic acid technique and the Schiller Test. Currently, colposcopes can record images with a photographic or video camera or even send them to a computer through a digital camera, obtaining the written diagnosis to be stored in a clinical file.

Introduced in 1928, the Schiller Iodine Test improved observation. Another improvement of the coloscopy from an optical point of view was the introduction of a green filter in 1939 carried out by Kraatz in Germany to evaluate vascular patterns of cervix tissue .

The Acetic Acid Test

The application of acetic acid when the mucous tissue is affected by HPV produces a coagulation of proteins, the intracellular keratin, that makes the tissue less transparent in approximately 40 seconds. The whitening that appears in these sick ephithelial cells is called acetowhite; the more it has been exposed to keratin the more visibly white it will become. The coloscopy takes into account the degree of whitening, the size, the shape of the edge of the lesion as well as the pattern that determines the degree of severity, named the coloscopic index.

Schiller Test

The Schiller Test or the idodine test consists in the application of a Lugol solution on the ephithelium: the healthy cells absorb the glucogen in this solution, staining themselves brown, while those infected with HPV are unable to do so.

Colposcopic Index

The degree of pathological signs of the neoplasias observed through the colposcopy are called coloscopic index. There are diverse opinions among the colposcopist depending on their experience as to which schema to use. In Reid’s Schema the thickness, color, shape and vascular abnormalities are studied and the acetic acid and iodine test are used; currently, it has undergone some modifications and is named “The Modified Reid Schema”. The Coppelson Schema/Method to determine the degree of neoplasia is based on the reaction of the acetic acid test .

“Classic” Colposcopy and Actinic Light Colposcopy

One of the limitations of the “classic” colposcopy is the degree of reliability-- false positives fluctuate between 4 and 33% and the false negatives between 40 and 62% due to the observer’s interpretation. There is a substantial number of subtle color differences that are difficult to perceive. Another factor that has an influence on limiting the observer is that there doesn’t exist a standard regarding the lighting technique required. Some sources of light for colposcopies are xenon, halogen, tungsten and LEDs, and as a result of these diverse sources, colors shine distinctively, with greater or lesser contrast, and are more or less saturated. And if you add the lack of uniform light intensity, the quality or clarity of the images will vary from that which is being observed and makes a diagnosis more difficult .

The actinic light colposcopy has up to 3% false positives and 13% false negatives, a difference that is due to the quality of the image from this instrument; this procedure improves the differenciation of image contrasts given that there is a dark or black background, with lesions superimposed in green tones.

Actinic Light Colposcopy

The Actinic Light Colposcopy is specific for viewing neoplasias, utilizing the knowledge of the fluorescence microscopy lens with episcopic lighting which means with incidental light on the focal point observed; using special fluorescent colorants called fluorochromes that make possible the staining of specific parts of the desired tissue cells, and as a result creating a high resolution image that is picked up through a system of specific filters and in this way highlights the image on a dark background (Stokes-Adams Law) .

The new system has a source of lighting similar to that used by microscopists, the Kohler illumination type, in which the filament of the bulb is focused into infinity on the observation plane which provokes the different subtlties to incresase the contrasts and colors and create an image of greater quality.

The technique of the actinic light colposcopy, in the areas of diseased tissue on which the acetic acid acts and through a traditional colposcopy which creates an almost transparent target, this type of coloscopy highlights in a green color on a dark background. A fixing agent like acetic acid faciliates the union of fluorochrome with the infected and injured HPV tissue.

For various reasons, the modification of the acetic acid technique makes possible a better view of the neoplasias. One of the reasons is the absorption of acetic acid with the fluorochrome and another because of the DNA absorption of fluorochrome in the neoplasic cells because they are found in a greater proportion than the healthy cells.

Advantages

This device and method has special and unique characteristics in addition to competitive advantages:

1.It’s portable, ergonomic and easy to use.
2.Light source of low heat intensity that avoids the heating of the colposcope.
3.Works as a common colposcope and as a actinic light colposcopy with a spectral light band with a specific wave length for the fluorochrome necessary for the detection of CINs.
4.The results are obtained at the same time the procedure is being carried out, in the same location where it is being performed.
5.The period of uncertainty is avoided with this procedure, given that the patient can receive information about what she is suffering from and the treatment to follow.
6.It lowers the costs of studies and procedures.

Invention

The device and method have been developed at Mexico City by the Doctors: Joel Gerardo Diaz Sanchez and Jose Gerardo Zertuche Zuani.

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