乳腺X射线摄影筛查中心

It has been proven that large numbers of women can be screened efficiently and effectively to detect breast cancers earlier resulting in lives saved, but to be efficient and effective, screening needs to be highly organized.In order to have a successful screening program the following components need to be optimized.

WHAT SERVICES WILL BE OFFERED

The singular, most important function for breast evaluation, is the early detection of breast cancer.  Screening is fundamental and the main reason for developing centers.  Nevertheless, it is critical, once a problem is detected, that the system is organized to efficiently provide the necessary follow-up care with diagnostic services and ultimately treatment services linked.

CONTINUITY OF CARE IS FUNDAMENTALLY IMPORTANT

Ideally a screening center will also have diagnostic capability so that when something is found at screening, whatever needs to be done to determine its significance can be performed expeditiously.  

If diagnostic services are not included in a screening center, then the center needs to identify diagnostic facilities to which women who are found to have a problem at screening can be referred.  It is even better if the screening center is linked to diagnostic services and also linked to therapeutic centers for complete, expeditious care.

Computerized records are fundamentally important to ensure continuity of care and the follow-up of patients.  This is important so that once a woman is in the system, her care and results can be monitored to ensure they are appropriate and complete.  Furthermore, those involved in the screening center need to be able to follow-up on their interpretations to check their accuracy, and to make changes when needed to insure “continuous quality improvement”.

REMINDER SYSTEM

It is important to determine what ages women should be screened and at what interval (time between screens).  The data show that the most lives are saved by annual screening starting at the age of 40.

Ideally each center, or the system to which it belongs, develops a database of women who use the system.  In addition to many critical measures that the system provides, the database can then be used to send out reminders for women when it is time for their annual screening.  

SCHEDULING

The overall organization should be designed to permit examining the maximum number of women efficiently and effectively.  Cancer detection rates commensurate with the age of the patients should be monitored.  Monitoring is also needed to ensure that cancers are being detected at a smaller size and earlier stage than in the absence of screening.

Each facility needs to determine how many women can be screened each hour and the hours of operation.

It is best to have patients make scheduled appointments so that screening can be planned and organized.

Ideally, if women schedule their appointments ahead of time, a reminder system is advised.  Women who schedule an appointment and then do not appear for that  appointment (“no shows”) take up valuable time and space and depending on the way that screening is funded, can be an economic problem.  Ideally a screening program will remind women several days in advance of their scheduled appointment.  If they are unable to attend women seeking earlier appointments can be added in.

Once a screening program is up and running, it will be easier to determine how much time is needed for each study.  The goal should be to have all the rooms occupied all the time, with little backup of women waiting for their study.

PREPARATION FOR SCREENING

Patients should be advised to not use any antiperspirant to their screening appointment since the components of these may show up on mammograms and simulate microcalcifications.

Women should be advised to wear separate clothing to facilitate removal of everything above the waist for the screening study.

THE DAY OF THE STUDY

Once a woman has checked into the screening center there should be two waiting areas.  

a. The first waiting area should have seating for women (and anyone who may accompany them) while they wait to move to the second area.  

b. Once called, each patient will move to the second waiting area where she will be able to remove her clothing from above the waist and be provided with either a disposable, or a cloth top (that can be laundered).  These tops should facilitate the exposure of each breast for imaging.  Lockers with keys are helpful.  Otherwise, women can bring their clothes and belongings into the screening room for the few minutes needed for the study.

Women are escorted from the “gowned waiting area” into the mammography room for the mammogram. 

Since the screening study is the only opportunity to detect an early cancer and reduce deaths, the screening study needs to be the highest quality possible.  The mammography devices used for screening need to provide the highest image quality possible.  It makes no sense to try to use less expensive, suboptimal systems since, if as a result, a cancer is missed, the opportunity will have been lost.  Having higher quality diagnostic systems will be of little importance if the cancer is not detected at screening.

The screening examination is the most important study.  The technologist should be highly skilled in positioning the breast and should be able to work with the patient to insure that the maximum amount of breast tissue is included on each study.

Many women are anxious so that everyone, especially the technologists, need to be understanding and supportive.

a. Women are anxious because they are “looking for breast cancer”

b. Their breasts are being exposed to a stranger

c. They are concerned that squeezing their breast will be painful or even harmful.

Technologists need to be highly skilled so that positioning and imaging can be accomplished rapidly, accurately, and with minimum of discomfort for the patient. 

Patients should be positioned to image as much breast tissue as possible.  Generally, it is most efficient to begin with the Mediolateral Oblique (MLO) of one breast followed by the Craniocaudal (CC) view of the same breast followed by the MLO of the other breast and finishing with the CC view of the second breast. 

Symmetrical positioning is critical since the breasts are symmetrical organs and will be view as mirror images.  An asymmetry can indicate a problem. 

When possible, the nipple should be in profile on all basic projections, but if this means that the deep tissues may not be imaged, the first image should be to image the maximum amount of tissue, and then, if needed, an additional image should be obtained with the nipple in profile.  This latter image is to be certain that a subareolar mass is not, falsely, dismissed as an out-of-alignment nipple or an out of alignment nipple is not misinterpreted as a subareolar mass.

Each image should be labeled with patient identifiers, date of the study, the side being imaged, as well as the projection used (MLO, CC, etc.)

Specific markers should be placed on the skin as needed to identify raised skin lesions such as using a semi-radiolucent circle for seborrheic keratoses or epidermal inclusion cysts.  Simply being pigmented does not mean that a skin lesion will appear on a mammogram so flat nevi or other non-raised skin lesions should not be marked to avoid cluttering the image.

Although women with clinically evident lumps should be evaluated in a diagnostic setting with a radiologist monitoring the study as it progresses, should a woman present with clinically evident lesion, this should be marked with a radio opaque “BB”.  The “BB” should be moved between images so that the x-ray beam goes through the “BB” and the lesion so that its location is directly under the “BB” on all views.

Working with the patient, the breasts should be positioned to maximize the tissues imaged without hurting the patient.  

Each breast should be compressed until the skin of the breast between the compression paddle and detector is “taut”.  Compression should not be painful.  Compression beyond “taut” will not add to the image quality since once the skin is tight the tissues will not be spread any further by additional compression, and this will only cause pain for the patient. 

The technologist should be certain that the skin is not pinched since this can be very painful.

Women with large breasts may require multiple images in each projection (tiling) to ensure that each breast is completely evaluated.

QUALITY CONTROL

Once the images have been obtained, they should be reviewed by the technologist while the patient is in the room (assuming digital imaging) to be certain that the positioning, compression, and exposure values are optimal.  On the MLO, the lower portion of the pectoralis major should be visible down to the axis of the nipple and the inframammary fold should be evident.  These provide the best evidence that visualization of the breast tissues has been maximized.

There should be no motion evident on the images.

All dense tissues should be penetrated to ensure that a lesion cannot be hidden. 

When possible, the nipple should be in profile, but if this means that the deep tissues may not be imaged, the first image should be obtained to image the maximum amount of tissue, and then if needed an additional image obtained with the nipple in profile.  

Once the images have been quality controlled by the technologist they should be sent for interpretation.  The patient leaves the examination room, dresses, and leaves the center.  Interpretation of the study may be done immediately if resources allow.  I do not think, however, that immediate reads are a good idea since they may be rushed, and, as a result, lesions overlooked.  Delayed – “batch reading” is the most efficient method allowing the radiologist undistracted time for careful review.  “Double reading” can also be facilitated to reduce the chance that a lesion will be missed by a single reader.

IMAGE INTERPRETATION

Interpretation of the studies should be done by skilled radiologists who interpret more than 500 screening cases a year (more is better).

Succinct, clear, and accurate “action oriented” reporting of the studies should be the rule.

A system is needed to store the interpretations.  It is also needed to efficiently convey the results to the referring physician, and to the patient in lay terms.

A system is needed for following up on all patients to be certain additional care, if needed, has been rendered and to determine outcomes.

A database that permits the results to be tabulated and reports issued to determine the accuracy of the studies and the results of the program so that, if needed, changes can be made to improve the system.