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Mammography : A Boon for Early Cancer Breast Detection

 

Ashok Kumar R Shukla*, Ashwini Bhalerao Gandhi**

 

Introduction
Breast cancer is the most frequently diagnosed
malignancy among American women, accounting for 32% of all cancers in this population.1 It is the second leading cause of cancer deaths (after lung cancer) among women of all ages and the leading cause of cancer deaths among women aged 40 to 59 years.1 Mammography has been shown to be efficacious in detecting breast cancer before it becomes clinically evident,2 and screening of asymptomatic women has become widespread as a means of achieving early detection. Routine screening with mammography is now generally accepted as a valuable tool for decreasing mortality from breast cancer. Increased life expectancy, Western oriented lifestyle have also led to increase in incidence of Ca breast in urban areas.

Aims and Objectives
Tools like mammography are not yet easily available in India. Very few centres are well equipped with these facilities and also the level of awareness in general population regarding these sophisticated but important investigations is very low. Thus not much data pertaining to Indian population with reference to mammography is available at present. We have tried here to find sensitivity of detecting breast carcinoma, incidence of breast carcinoma and its relation with age and parity in women above 40 years of age.

Material and Methods
We evaluated successive 200 women attending Well Women clinic at PD Hinduja Hospital from Jan. 2002 to Dec. 2003 and the results, mainly Mammography, are analyzed here. Well women health check package is for women who are postmenopausal, want to know and start HRT, already on HRT, h/o irregular and heavy menses, lump in breast, family h/o breast cancer, ovarian cancer or uterine cancer, persistent or chronic white discharge per vaginum, early menopause, h/o early hysterectomy, or are above 40 years of age.

All cases in our study have voluntarily opted for this package. All cases undergo BMD, Mammography, USG pelvis, X-ray chest, ECG and other basic investigations.

Observations and Analysis
All 200 cases of our study group were analyzed according to their age group as follows:

Maximum number of women enrolled in this package was between age group 45-50 years

Only 4% of women were above 65 years of age. None of the women in our study was on HRT.

The breast imaging reporting and data system (BI-RADS) lexicon was developed by the American College of Radiology (ACR) to standardize mammographic reporting.3

In the study group, after assessing mammograms categorized according to BI-RADS Lexicon.

Total 06 mammograms were categorized as suspicious requiring further evaluation like FNAC and Biopsy. 2 were fibroadenomas, 2 had malignancy, 2 were lost to F/U. There were no women in category 0 and 5. 2.5% of patients were advised to repeat after 6 months.

Profile of Women Diagnosed to have Malignancy on FNAC

Both patients were above 45 years of age and had first child-birth (at around 30 yrs of age).

Both age and late first child-birth are important factors increasing the incidence of breast cancer.

Discussion
In India breast cancer is the second common malignancy after cervical cancer and is detected in 20 per 1,00,000 women. The incidence is increasing in most countries at the rate of 1 to 2% annually and soon nearly one million women will develop this disease every year throughout the world.4 In our study out of 200 women who underwent mammography 2 had breast carcinoma detected in early stage. Incidence is 1%.
The positive predictive value was found to be :

No. of cancers documented = 02 x 100 = 34%
No. of individuals that undwerwent biopsy 06

In three published series the frequency of carcinoma was significantly higher for BI-RADS category 5 (suggestive of malignancy) than for category 4 (suspicious), ranging from 81% to 97% for category 5 versus 23% to 34% for BI-RADS category 4.5

The two strongest risk factors for breast cancer are age and family history of breast cancer. The other risk factors like late age at first child birth, nulliparity, diet, obesity, no breast feeding, hormones account for 20-29% of breast cancers.6 Breast cancer increases in frequency with increasing age.

In our study both women whose FNAC had come positive for breast malignancy had no family history of Ca, were about 45 years of age and had late 1st child birth. Nulliparity and late age at first childbirth, both increase the lifetime incidence of breast cancer.7

Evidence for the benefit of screening mammography in reducing mortality from breast cancer largely derives from several large randomized controlled trials (RCTs) conducted in North America and Europe beginning in the 1960s and involving a combined total of nearly 500,000 women.8,9 In addition to decreasing mortality from the breast cancer, the use of screening mammography has been shown to result in the diagnosis of smaller and more node-negative tumours.9 In a recent update of the experience of the Swedish two country screening trial, Tabar et al10 reported that 50% of screening detected cancers were in good prognostic category (generally stage 0 or 1, depending on histological type) as opposed to 19% in the clinically detected group.

For those women whose cancer is detected by screening mammography before it becomes palpable mass, needs less aggressive therapy options like lumpectomy followed by radiation therapy rather than mastectomy and decreased need for systemic chemotherapy.11

In both the patients from our study group, FNAC came as invasive duct carcinoma and hence underwent mastectomy with radiation and their nodes were negative.

The US Preventive Services Task Force and American Medical Women’s Association and ACS recommend screening mammography, with or without clinical breast examination every 1-2 year for women aged 40 and older. Mammography can detect approximately 85% of breast cancers.

Screening Recommendations
Screening mammography, despite its limitations, remains the best means for diagnosing breast cancer in asymptomatic women. Regarding the continuing controversies concerning the age at which screening should start, evidence supports beginning regular screening at age 40 in women at average risk.12 Similarly evidence suggests that the screening interval should be yearly, especially in your women.13 Rather than an arbitrary age at which screening should stop, the decision on screening elderly women should be made on individual basis, taking into account level of health and life expectancy. More work to be done on determining the optimum screening strategies for high-risk women. The impact of double reading and computer aided detection in the interpretation of screening mammograms warrant further evaluation in terms of efficacy and cost effectiveness.

Despite these continuing controversies, mortality from breast cancer in the United States has been decreasing steadily for the past 25 years.13 The magnitude of the decrease has been reported anywhere in the range from 8% to 25%.14 Although some amount of decrease may be attributable to improvements in the treatment of breast cancer, early detection through screening mammography has undoubtedly played a role in this mortality reduction. The controversies that surround the issue of screening should not detract from the fact that screening mammography has proved to save lives.15

References

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  3. American College of Radiology. Illustrated breast imaging reporting and data system (BI-RADSTM) Reston, VA: American College of Radiology; 1998.
  4. Liberman MA, Mitchell D, Hollingworth AB. Positive predictive value of the breast imaging reporting and data system. J Am Coll Surg 1999; 189 : 34-40.
  5. Nichols DH. The epidemiologic characteristics and breast cancer. Clin Obstet Gynecol 1994; 37 : 925-32.
  6. White E. Projected changes in breast cancer incidence due to the trend of delay in childbearing. Am J Public Health 1987; 77 : 495-7.
  7. Miller AB, Bainer CJ, To T. Canadian national breast screening study: 1: Breast cancer detection and death rates among women aged 40 to 49 yrs. Can Med Assoc J 1992; 147 : 1459-76.
  8. Miller AB, Bainer CJ, To T. Canadian national breast screening study: 2 : Breast cancer detection and death rates among women aged 50 to 59 yrs. Can Med Assoc J 1992; 147 : 1477-88.
  9. Change HR, Cole B, Bland KI. Nonpalpable breast cancer in women aged 40-49 yrs: a surgeon’s view of benefits from screening mammography. Monor Natl Cancer Inst 1997; 22 : 145-9.
  10. Tabar L, Vitak B, Chen H-H, Duffy SW, Yen MF et al. The Swedish two countries trial. Twenty years later. Radiol Clin North America 2000; 38 : 625-52.
  11. Jain AK. Fundamentals of digital image processing. Prentice hall; 1988.
  12. Kerlikowske K. Efficacy of screening mammography

    among women aged 40 to 49 years and 50 to 69 yrs.: Comparison of relative and absolute benefit. Monogr J Natl Cancer Inst 1997; 22 : 79-86.
  13. Committee opinion number 247. Washington, DC: American College of Obstetrician and Gynaecology, December 2000.
  14. Chu KC, Tarone RE, Kessler LG, Reis LAG, Hankey BF, et al. Recent trends in US breast cancer Incidence, survival and mortality rates. J Natl Cancer Inst 1996; 88 : 1571-9.
  15. Petro R, Boreham J, Clarke M, Davies C, Bereal V. UK and USA breast cancer deaths downs 26% in year 2000 at ages 20-69 yrs. Lancet 2000; 355 : 1822.

 


*Registrar; **Consultant Gynaecologist; Department of Gynaecology, PD Hinduja Hospital, Mumbai.

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