The mammography has a great ability to detect cancer in situ: Is it a good thing?
Nearly all breast cancers are born inside the channels leading breast milk. When cancer cells proliferate outward invading surrounding tissue, it’s called invasive cancer. The in situ cancer is not a cancer but a precancerous lesion developed within the channels. These lesions contain cancerous cells appearance that will rarely grow outside channels to invade surrounding tissue, they will no longer life threatening. In other words, only a few cancers in situ, will become invasive cancers.
Lesion in situ malignant cells in the canals
Invasive Cancer: spans of malignant cells invading the surrounding tissues
But all women diagnosed for cancer in situ, will be operated either by surgically total removal of the breast, or by removal of the lesion with sometimes radiotherapy.
The detection of lesions in situ can be an advantage for those with a lesion become invasive. But this may have a major disadvantage for those who will be treated surgically and with a lesion would not become invasive.
A large study of women in their sixties who participated in mammography screening has shown that the risk of having a diagnosis of in situ lesions were multiplied by 4 compared to women not undergoing a simple routine clinical examination. But the same number of deaths from breast cancer had been warned that it is among women subjected to screening mammography or among those subject to simple clinical breast examination. Thus the interest of detecting lesions in situ by mammography is not clear.
If 10000 women 40 years undergo a mammogram annually over 10 years, 40 to 50 will be diagnosed with cancer in situ.
If 10000 women 50 years undergo a mammogram annually over 10 years, 70 to 120 will be diagnosed with cancer in situ.
If 10000 women 60 years undergo a mammogram annually over 10 years, 110 to 120 will be diagnosed with cancer in situ.
If 10000 women 70 years and undergo a mammogram annually over 10 years, 95 to 150 will be diagnosed with cancer in situ.
The probability that a woman of 40 years of age and older who had a diagnosis of cancer in situ Treaty, has died of an invasive breast cancer within 10 years is about 2% (approximately 2 for every 100 women)
References
M Nielsen, Thomsen JL, Primdahl S, Dyreborg U, Andersen JA.Br J Cancer. 1987 Dec; 56 (6) :814-9. Breast cancer and atypia among young and middle-aged women: a study of 110 medicolegal autopsies
Ernster VL, Barclay J, Kerlikowske K, Grady D, Henderson IC. Incidence of and treatment for ductal carcinoma in situ of the breast. JAMA 1996; 275:913-918.
Kerlikowske K, J. Barclay Outcomes of modern screening mammography. Monogr Natl Cancer Inst 1997; 22:105-111
Ernster VL, Barclay J, Kerlikowske K, Wilkie H, Ballard-Barbash R. Mortality among women with ductal carcinoma in situ of the breast cancer population in the SEER Program. Arch Intern Med 2000; 160:953-958.
May DS, Lee NC, Nadel MR, Henson RM, DS Miller. The National Breast and Cervical Cancer Early Detection Program: report on the first 4 years of mammography provided to medically underserved women. Am J Roentgenol. 1998; 170:97-104
Kerlikowske KM, Grady DG, Barclay J, Sickles EA, Eaton A, Ernster V. Positive predictive value of screening mammography by age and family history of breast cancer. JAMA 1993; 270:2444-50.
Miller AB, To T, Baines CJ, Wall C. Canadian National Breast Screening Study-2: 13-year results of randomized trial in women aged 50-59 years. JNCI 2000; 92:1490-9.
