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"Ask Dr. Cook" is a series of questions and answers regarding endometriosis. The current subject and answer can be found on Current Ask Dr. Cook web page. The questions may represent a summary of questions I have been asked by several different patients. I hope you find this information helpful. If you have a question you would like answered, please Submit A Question.
Question: Answer: OVERVIEW OF CLASSIFICATION SYSTEMSFirst, let's clear up some terminology. Classification is defined as "arrangement according to some systematic division into classes or groups". Stage is defined as "the level or degree in a process of development, growth or change". The endometriosis classification system contains four stages (Stage I, Stage II, Stage III, & Stage IV) of disease severity. The purpose of a classification system is to identify the relative the severity of a disease process. The more severe the disease, the greater the health risk to the patient. Mild disease would be less serious than severe disease. The ramifications of increasing disease severity is obvious when used in staging cancer. The more severe the stage, the more likely that the disease has spread and the less likely the patient will survive. Endometriosis is not a cancer and it does not threaten your physical survival. Although those of you who have dealt with endometriosis personally, either yourself or others in your life, understand the toll it can take on your life in so many different ways.The two primary problems women experience with endometriosis are infertility and pelvic pain. An ideal endometriosis classification system would determine the severity of disease based upon the degree of infertility or pelvic pain and would predict the probability of success of any given treatment. The difficulty arises in the fact that we, as a medical profession, do not have a level of understanding of this disease to know how to measure these parameters. If we knew exactly how endometriosis effected fertility, then we could create a test that would measure the amount of this change. The same goal applies to endometriosis related pelvic pain. This approach would determine the severity of endometriosis as it relates to infertility or pelvic pain. The current classification system was created with the goal of predicting
a patients future fertility based on her stage of endometriosis. Unfortunately,
at this time the current endometriosis classification system does not
predict a woman's chance of pregnancy. The pregnancy rate of a woman treated
with Stage IV endometriosis is the same as a woman treated for Stage I
disease. This classification system was not intended to, nor is it successful
in, predicting the amount of pain a woman experiences. It does not predict
the chance of pain relief following treatment.
HISTORY OF THE ENDOMETRIOSIS CLASSIFICATION SYSTEMMany different endometriosis classification systems have been proposed since the initial system of Wicks and Larson (1949), which was based on the microscopic appearance of endometriosis. In 1951, Huffman proposed a classification system, similar to the staging system used for cervical cancer, which was based on the size and location of the endometrial implants. The current classification system is, by and large, an evolution of this Huffman's staging system. During the 1970's multiple endometriosis classification systems were proposed. These numerous classification systems led to confusion and a lack of consensus. This prompted the American Fertility Society (AFS) to appoint a committee with representatives from many of the previous classification systems to create an a uniformly acceptable endometriosis classification system.The original AFS classification system was published in 1979. The stated goal of this classification system was to predict the chance of conception after treatment of endometriosis. This classification system was never intended to predict the amount of pain a patient experienced as a result of endometriosis, nor the chance of pain relief after treatment of the endometriosis. The AFS classification system used a point system for staging endometriosis. A certain number of points were assigned in various categories. These categories included the degree of endometriosis present on the ovaries, peritoneum, cul-de-sac obliteration, etc. The cumulative number of points determined the stage (mild, moderate, severe or extensive) of endometriosis. Dr. John Rock and colleagues published a couple of studies in the early 1980's which evaluated the AFS classification system. They felt that there were two major limitations of this system. They were concerned that the weighting of the various categories did not correctly reflect the impact on fertility. Second, the cutoff points of the total AFS score for each stage were arbitrarily assigned. It was felt that these factors limited the ability of the AFS classification system to predict the chance of pregnancy after treatment of the endometriosis. The revised AFS (R-AFS) classification was approved in 1985. This included
changes that attempted to correct the limitations of the initial classification
system. This is a more detailed system which recognizes the difference
between superficial and invasive disease and changed the terminology of
the four stages to minimal, mild, moderate and severe. The American Fertility
Society was renamed the American Society for Reproductive Medicine (ASRM)
in 1995. The Endometriosis Classification for Infertility Subcommittee
of the ASRM collected data from several centers to evaluate the the R-AFS
classification system and pregnancy rates. The study was published in
the May issue of Fertility and Sterility. The authors concluded that there
was no correlation between stage of endometriosis as determined by the
R-AFS classification system and pregnancy rates. The last sentence of
the article states "At the very least, our results suggest that fine-grained
distinctions between patients with respect to point scores, although useful
for documentation, are not clinically useful with respect to the prognosis".
(chance of pregnancy) There was data accumulating that suggested that
the appearance of the endometrial implants might correlated with their
biologic activity and thus pregnancy rates. The additional recommendation
of recording the appearance of the endometrial implants was made in 1996.
CURRENT ENDOMETRIOSIS CLASSIFICATION SYSTEMThe "Revised American Society for Reproductive Medicine Classification of Endometriosis: 1996" is currently the most widely used system to stage endometriosis. Figure 1 is the chart of this classification system produced by the American Society for Reproductive Medicine. This is what your physician uses when calculating you stage of endometriosis. Figure 2 provides examples and guidelines for use of the classification system. This material is reprinted by permission from the American Society for Reproductive Medicine (Fertility and Sterility, 1997, Vol. 67, No. 5, Pages 819 - 820). Figure
1. Revised American Society for Reproductive Medicine Classification System:
1996 Figure
2. Examples and Guidelines for the R-ASRM 1996 Endometriosis Classification
System
This classification system is basically the R-AFS system based upon the size, location, depth of invasion of endometrial implants and the amount of scar tissue involving the ovaries and fallopian tubes. In addition the appearance of the endometrial implants are classified as red, white and black. The red lesion category includes red, red-pink and clear lesions. The white lesion category includes white, peritoneal defect and yellow- brown lesions. The black lesion category includes both black and blue lesions. Perhaps the addition of the physical appearance of the endometriotic lesions will help improve the accuracy of the classification system in predicting the chance of pregnancy following treatment of endometriosis. The classification system does not apply to patients with endometriosis related pain. As the mechanisms by which endometriosis causes infertility and pain are better understood, a more refined and useful classification system will be possible. Until that time, the classification system provides a means to concisely document the surgical findings. A video tape of the surgery will provide the most accurate record and should be included as a part of the medical record of all patients undergoing laparoscopic evaluation and treatment. This will allow "re-staging" of a patient's endometriosis as the current classification system is refined and future classification systems are created.
Updatede October 29, 2005
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