A look at utilization and cancer detection yield of mammography.

A call for review of its indication and cost-effectiveness.

Reynaldo O. Joson, MD, FPCS

Cathy S. Co, MD

Manila Doctors Hospital

Abstract

In the Philippines, mammography is now frequently requested in the evaluation of patients with a breast cancer concern. The general objective of this study is to take a look at the practice of requesting for a mammography in a health care institution and its outcome in terms of cancer detection in patients with no palpable breast mass. Review of past records was accomplished. A total of 7,323 mammographies was done from 1994 to 2001. Three per cent (192 persons) were done in the 20-29 age group; 13% (966 persons) in 30-39 age group; 37% (2708 persons), 40-49 age group; 33% (2410), 50-59 age group; and the remaining 14% (1047), in those older than 60 years old. The top three

physicians requesting for mammography were obstetrician-gynecologists (32%), general surgeons (18%), and internists and family medicine specialists (10%). Normal findings were reported in 61%; benign, 37%; suspicious for cancer without a clinically palpable mass, 1% (99 patients); and suspicious for cancer with a palpable breast mass, less than 1% (52 patients). A total of 50 patients underwent needle localization biopsy of which 35 had fibrocystic changes (70%); 10 had cancer (20%); and 5 with indefinite results. The overall cancer detection yield of mammography in those without a palpable breast mass, 7271 (7323-52) persons, was extrapolated to be 0.28% (20/7271). The authors deemed the information gotten in this study would be useful to the public, health care administrators, and health care providers in reviewing the indication and cost-effectiveness of mammography.

A look at utilization and cancer detection yield of mammography.

A call for review of its indication and cost-effectiveness.

Reynaldo O. Joson, MD, FPCS

Cathy S. Co, MD

Manila Doctors Hospital

Introduction

Mammography probably started in the Philippines in the early 1990s. Over the past 10 years or so, it has progressively and rapidly become very popular and in the public perception, it has become synonymous with breast cancer screening.

Noting that it is being widely used, the authors, who are general surgeons managing patients with breast problems, raised a question on the status on mammography utilization in the country. They decided to conduct a study to take a look at the practice of requesting for a mammography and its outcome in terms of detection of cancer in patients with no palpable breast mass. They decided to do the study in a private health care institution for a starter.

Specifically, they wanted to gather data on the following:

1. Frequency of requests for mammography

2. Type of physicians requesting for mammography

3. Age distribution of persons undergoing mammography

4. Results of mammography in terms of normal benign, suspicious for cancer with and without clinically palpable mass

5. Frequency of needle localization and its results

6. Overall cancer detection rate of mammography in persons with persons without a palpable mass

Methods

Mammography results were borrowed from the Department of Radiology of the Manila Doctors Hospital. The period covered was from May 1994 to December 2001, the time frame since mammography started in the hospital. The mammography results were tabulated according to the number of mammograms done per year, stratified according to age groups and type of specialty/medical personnel requesting for mammograms.

The results were classified into normal, benign, suspicious for cancer without a clinically palpable mass and suspicious for cancer with a clinically palpable mass. The number of needle localization biopsies was obtained and the histopathology results were followed up in the Pathology Department.

Results

A total of 7,323 mammography results were retrieved. There was an increasing number of mammographies being done from 1994 to 2001 with an average of 1300 per year and 110 per month from 1998 to 2001. (Table 1)

Three per cent (192 persons) were done in the 20-29 age group; 13 per cent (966 persons) in 30-39 age group; 37 per cent (2708 persons), 40-49 age group; 33 per cent (2410), 50-59 age group; and the remaining 14 per cent (1047), in those older than 60 years old. About 53 per cent were done on persons under 50 years old. (Table 2)

With regards to the type of physicians requesting for mammograms, the top three were obstetrician-gynecologists, general surgeons, and specialists in internal medicine and family medicine. (Table 3)

With regards to mammographic findings, majority of mammography results were normal (60.75 per cent); benign, 37.16 per cent; suspicious for cancer without a clinically palpable mass, 1.35 per cent; and suspicious for cancer with a clinically palpable mass, less than 1 per cent. (Table 4)

Of the 99 mammographic results which were suspicious for cancer without a clinically palpable mass, only 50 of the patients underwent needle localization biopsy. Thirty-five (70 per cent) showed fibrocystic change; 10 (20 per cent) showed carcinoma; 5 had indefinite result.

The overall cancer detection yield of mammography in those without a palpable breast mass, 7271 (7323-52) persons, was extrapolated to be 0.28 per cent (20/7271). If all the 99 patients with suspicious for cancer were to undergo needle localization biopsy, assuming a 20% positivity rate, then a total of about 20 in the population of persons without a palpable breast mass would have a diagnosis of cancer.

Table 1. Frequency of mammography done in Manila Doctors Hospital, 1994-2001.

Year	Number
1994	101
1995	633
1996	372
1997	872
1998	1409
1999	1548
2000	1111
2001	1277
Total	7323

Table 2. Age distribution of persons undergoing mammograms.

Age	Number	Per cent	Per cent
20-29	192	2.62	52.80
30-39	966	13.19
40-49	2708	36.98
50-59	2410	32.90	47.20
60-92	1047	14.30
	7323

Table 3. Type of physicians requesting for mammography.

Type of Persons	Number	Per cent
Obstetrician-Gynecology	2337	31.90
Unknown specialization	2107	28.77
General Surgery	1348	18.40
Not indicated	694	9.48
Internal Medicine	453	6.19
Family Medicine	353	4.82
Radiology	12	0.16
Pediatrics	5	0.07
Opthalmology	5	0.07
Anesthesiology	4	0.05
Pathology	2	0.03
Rehabilitation Medicine	2	0.03
Otorhinolaryngology	1	0.01
	7323

Table 4. Mammographic results.

Mammographic Results	Number	Per cent
Normal	4449	60.75
Benign	2721	37.16
Suspicious for cancer without clinically palpable mass	99	1.35
Suspicious for cancer With clinically palpable mass	54	0.74
	7323

Table 5. Histopathology results of needle localization biopsy of suspicious mammographic findings without clinically palpable mass.

Histopathology result	Number	Per cent
Fibrocystic changes	35	70
Cancer	10	20
Indefinite result	5	10
	50

Discussion

The data thus gathered have given the authors a glimpse on the status of mammography utilization in a private health care institution in Metro Manila. Whether it is reflective of the status in other health care institutions throughout the country is a question that the authors are interested in pursuing. The authors plan to embark on a multicenter study to gather more data to get a wider picture, nationwide if possible, on mammography utilization and its outcome in terms of cancer detection yield in patients with no palpable breast mass.

As they are, the data gathered so far show a rampant usage of mammography among those persons less than 50 years old (about 53 per cent) which should not be if the present universally accepted cut-off of 50 years old is to be followed. The data also show a very low yield of cancer (less than 1 per cent). The authors believe these findings call for a review of the guidelines in the usage of mammography and its cost-effectiveness.

The authors while completing this study came across an unpublished paper on mammography utilization in a health care institution in Cebu (1). The findings were practically the same – increasing utilization; 68 per cent done in persons less than 50 years old; same top three kinds of physician-prescriber; and low 5 per cent suspicious for cancer findings. The report did not include needle localization and overall cancer detection yield in those with no palpable breast mass.

The use of mammography is still fraught with a lot of uncertainties, starting from whether it really is beneficial in terms of reducing mortality from breast cancer to whether it really is cost-effective, and if it is, at what age group, 40-49, 50-59, or 60 and older.

Prior to the turn of the century, 2000, there seems to be a universal consensus in believing that mammography is beneficial and is cost-effective in persons 50 years and older. What is not settled during this time is the question whether mammography is cost-effective even in persons 40-49 and those older than 60 years old. Most recently, 2001, a report seriously questions whether mammography really reduces mortality from breast cancer or not (2).

In view of this newest finding questioning the usefulness of mammography, all the more the authors feel that mammography utilization in the Philippines should be reviewed and guidelines put up to promote a rational usage.

At any rate, even without a more representative and extensive data yet, the authors feel that the information produced by this study will already be useful to the public, health administrators, and health care providers. The laypeople can benefit by becoming aware of the percentage of cancer detection by mammography in nonpalpable breast masses. The health administrators, such as the Department of Health, local medical sectors, and medicare providers, will be made aware of the issue of cost-effectiveness of mammography in detecting cancer in nonpalpable breast masses and may be prompted to review current policies and formulate new guidelines if needed. Lastly, the health care providers can benefit from the information by being able to educate and inform their patients with evidence-based data, determine the cost-effectiveness of mammography, and to be more aware of the use and advantage of mammography in relation to their practice.

References:

1. Atilano AA, Siguan SS, Medalle ER. Patterns of mammogram utilization and clinical profile of patients who underwent mammography at Cebu (Velez) General Hospital, Cebu City, Philippines. 2001.

2. Olsen O, Gøtzsche PC. Cochrane review on screening for breast cancer with mammography. Lancet 2001;358:1340-1342.