Is there a survival benefit to screening mammography and what is the optimal screening and diagnostic algorithm?

OVERVIEW: For years, mammography has been widely accepted as the gold standard for breast cancer screening. The main controversies surrounding mammography have been issues such as what age to begin screening or what type of mammography is best (screen-film versus digital), rather than whether or not to screen women. Indeed, the largest open breast cancer screening clinical research trial in the United States today compares the screening and diagnostic value of digital mammography to screen-film mammography. In 2000, a Cochrane review challenged the value of screening mammography stating there was no reliable evidence that breast cancer screening reduced mortality. Other imaging modalities, such as ultrasonography and MRI, are being considered for screening. At this time, however, they are utilized only in specific patient populations or clinical trials. In addition to screening controversies, there are numerous questions about the most effective way to biopsy a suspicious lesion. Once a breast abnormality is discovered, numerous diagnostic modalities exist including, but not limited to: diagnostic mammography, ultrasound, MRI, fine needle aspiration, Mammotome, core biopsy, needle localization and surgical excision. Image-guided interventional procedures offer high accuracy for the diagnosis of nonpalpable suspicious lesions, generally without any lasting post-procedure changes on follow-up mammography.

Do you believe that screening mammography significantly lowers the chance of dying from breast cancer?

Do you believe that screening mammography significantly lowers the chance of requiring mastectomy to treat breast cancer?

Which biopsy technique(s) are used most often for palpable breast masses suspected to be cancer?

Which biopsy technique(s) are most commonly used for nonpalpable microcalcifications that are negative on ultrasound?

Which biopsy techniques are most commonly used for a nonpalpable mass that on ultrasound is identified to be a solid lesion?

THE SCREENING MAMMOGRAPHY DEBATE

There is no evidence that clinical examination, breast ultra sonography, or teaching self examination of the breast are effective tools for early detection. However, randomised controlled trials have shown that screening by mammography can significantly reduce mortality from breast cancer by up to 40% in those who attend. The benefit is greatest in women aged 50-70 years. Published data from the combined Swedish trials showed an overall reduction in breast cancer mortality of 29% during 12 years of follow up in women aged over 50 who were invited for screening.

—Blamey RW et al. BMJ 2000;321(7262):689-93.
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In 2000, we re p o rted that there is no reliable evidence that scre e n i n g for breast cancer reduces mortality. As we discuss here, a Cochrane review has now confirmed and strengthened our previous findings. The review also shows that breast-cancer mortality is a misleading outcome measure. Finally, we use data supplemental to those in the Cochra n e review to show that screening leads to more aggressive treatment . . . We have provided detailed evidence on the mammography screening trials, and hope that women, clinicians, and policy-makers will consider these findings carefully when they decide whether or not to attend or support screening programmes. Any hope or claim that screening mammography with more modern technologies than applied in these trials will reduce mortality without causing too much harm will have to be tested in large, well-conducted randomised trials with all-cause mortality as the primary outcome.

—Olsen O, Gøtzsche PC. Lancet 2001;358(9290):1340-2.
Abstract

Sir Ole Olsen and Peter Gøtzsche’s full report ... is riddled with misrepresentation, inconsistency in the treatment of the randomised trials, and errors of method and fact...

The [report does] not inspire confidence in Olsen and Gøtzsche’s judgment of study quality or for the notion that all-cause mortality is an appropriate endpoint. As if deaths from road-traffic accidents or hip fractures were in some way indicative of the effect of breast-cancer screening. We believe that Olsen and Gøtzsche referring readers to a website for details of why they were right all along, is a clever and convenient way of subverting the peer review process and shielding their work from proper scientific scrutiny. The full report is not the official Cochrane review, despite its misleading title. Olsen and Gøtzsche’s review is of poor quality, and, therefore, unreliable. Given this poor quality, Horton’s uncritical commentary is at best ill considered. Nothing in the report or commentary disproves the finding of millions of person-years of experimental research, and dozens of previous expert reviews, that mammographic screening significantly reduces mortality from breast cancer.

—Duffy SW et al. Lancet. 2001;358(9299):2166.

ULTRASOUND AND MRI FOR SCREENING

Ultrasonography and magnetic resonance (MR) tomography are helpful tools to evaluate unclear lesions found at screening mammography. Ultrasound is particularly useful to prove the presence of a cyst or to further examine unclear, asymmetrical densities. With MR mammography, carcinomas can be found even when x-ray mammography or ultrasonography are limited due to diffuse, benign, proliferative changes. Ultrasound guidance has greatly facilitated core needle biopsy for suspicious lesions. Additionally, approved devices for MR-guided biopsy are commercially available. As a primary screening tool, ultrasound or MR mammography may be used only in women who are positive for BRCA-1 or BRCA-2 mutations or who are otherwise at high risk for breast cancer.

—Delorme S. Radiologe 2001;41(4):371-8.
Abstract

RADIOLOGICAL INTERVENTIONAL PROCEDURES

Radiological interventional procedures on the breast are still work in progress. Initiation of percutaneous macrobiopsy techniques such as stereotactic or ultrasound-guided core biopsy, mammotomy or Abbi Site-Select procedures allows the physician to expect a high accuracy for the diagnosis of non palpable suspected breast abnormalities, thus eliminating the need for at least half of the surgical biopsies done for this indication. Furthermore, the absence of any lasting post-procedural changes on follow-up mammography contrasts with the scarring associated with traditional surgical open biopsy and obviates confusion in subsequent mammographic interpretation. Recently, development of percutaneous radiofrequency or cryotherapy ablation of breast cancer has been related. All these cost-saving procedures lead to medical and potential medical legal pitfalls.

—Marcy PY et al. Bulletin du Cancer 2001;88(12): 1159-1166.
Abstract

ACRIN-6652: SCREENING AND DIAGNOSTIC STUDY OF DIGITAL MAMMOGRAPHY VERSUS SCREEN-FILM MAMMOGRAPHY IN THE DETECTION OF BREAST CANCER IN WOMEN OPEN PROTOCOL

PROJECTED ACCRUAL: 49,500 patients

Protocol: All patients undergo a two-view digital and a two-view screen-film mammography of each breast. Quality of life assessments are performed in the first 800 patients before mammography screening and 1200 (600 with positive screening results and 600 with negative screening results) after screening.

STUDY CONTACT Etta Pisano, Chair Phone: 919-966-6957 American College of Radiology Imaging Network

UPCC-ACR-6884: SCREENING AND DIAGNOSTIC STUDY OF MAGNETIC RESONANCE IMAGING IN WOMEN WITH SUSPECTED BREAST CANCER OPEN PROTOCOL

PROJECTED ACCRUAL: 420 patients

Protocol: Physical exam, two-view screening mammogram and MRI with gadolinium contrast. All suspicious lesions undergo a core needle or excisional biopsy.

STUDY CONTACT Mitchell Schnall, Chair Phone: 215-662-7238 University of Pennsylvania Cancer Center

COCHRANE REVIEW: ALL-CAUSE MORTALITY IN MEDIUM-QUALITY SCREENING TRIALS AFTER 13 YEARS.

Study	Screened		Not Screened		Relative Risk*
	# of Deaths	# of Women	# of Deaths	# of Women	(95% CI)
Malmö 1976	2537	21088	2593	21195	0.98 (0.93-1.04)
Canada 1980a	418	25214	414	25216	1.01 (0.88-1.16)
Canada 1980b	734	19711	690	19694	1.06 (0.96-1.18)
Subtotal	3689	66013	3697	66105	1.00 (0.96-1.05)

*Fixed effects model Adapted from Olsen O, Gøtzsche PC. Lancet 2001;358(9290):1284-5 Abstract

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