For Breast Cancer, When to Screen or Not to Screen? That Is the Question Plaguing the Minds of U.S. Women — and Their Clinicians

FORT WASHINGTON, PA—(Marketwired – April 18, 2016) – In 2015, American Cancer Society (ACS) caused a stir in the oncology community — and among women in general — with the updated recommendation that women of average risk for breast cancer should commence annual mammography at age 45. Previously, ACS recommended that mammography begin at 40 years, which is the same age recommended within the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Breast Cancer Screening and Diagnosis. Moreover, the U.S. Preventive Services Task Force (USPSTF) recommended age 50. 

Because breast cancer is the most prevalent cancer as well as the second leading cause of cancer death in U.S. women, the community wants answers.[1]

To shed light on the screening conundrum, the National Comprehensive Cancer Network® (NCCN®) brought together experts from the three leading guidelines organizations to discuss the screening controversies during its 21st Annual Conference on April 2, 2016.

Facilitated by Mary Lou Smith, JD, MBA, Co–Founder, Research Advocacy Network, and 21–year member of the NCCN Guidelines® Panel for Breast Cancer, the panel included Therese Bevers, MD, The University of Texas MD Anderson Cancer Center, representing NCCN; Kirsten Bibbins–Domingo, MD, PhD, MAS, University of California, San Francisco, representing USPSTF; and Kevin Oeffinger, MD, Memorial Sloan Kettering Cancer Center, representing ACS.

Following are citations for the three organizations' recommendations:

  • ACS: Oeffinger KC, Fontham ET, Etzioni R, et al. Breast Cancer Screening for Women at Average Risk: 2015 Guideline Update from the American Cancer Society. JAMA 2015;314:1599–1614
  • NCCN: NCCN Clinical Practice Guidelines for Breast Cancer Screening and Diagnosis (Version 1.2015) © 2015 National Comprehensive Cancer Network, Inc. Available at NCCN.org. Accessed [March 28, 2016].
  • USPSTF: Screening for Breast Cancer: U.S. Preventive Services Task Force Recommendation Statement. Ann Intern Med 2016; 164:279–296.

The panel agreed that indeed there are benefits to breast cancer screening. However, there is debate over whether those benefits outweigh potential negative effects and as to where the value lies in cancer screening. And the conclusions vary by one's point of view.

In establishing treatment guidelines, experts consider not only reduction in breast cancer mortality, but in treatment–related morbidity, as well, said Dr. Bibbins–Domingo, who is the Lee Goldman, MD Endowed Chair in Medicine and Professor of Medicine and of Epidemiology and Biostatistics at UCSF School of Medicine.

According to Dr. Bibbins–Domingo, USPSTF has relied on randomized controlled trials and more than 200 observational studies to develop models for their evidence–based guidelines. She noted that observational studies are necessary to capture data on the newest screening techniques.

With old film screens from the 1970s and 80s, the randomized clinical trials for breast cancer screening showed about a 20% reduction in mortality, explained Dr. Oeffinger, Primary Care Physician and Director of the Cancer Survivorship Program at Memorial Sloan Kettering Cancer Center. Today's observational studies, in contrast, show that mammography is reducing mortality by closer to 30–35% in certain populations. The ACS recommendations are influenced by the burden of disease and the potential benefits and harms associated with screening, focusing on 5–year increments in age, he said.

The NCCN Guidelines Panel for Breast Cancer Screening and Diagnosis considers both the randomized clinical data and the data from modern screening used in the observational studies, noting that women who are screened are less likely to be diagnosed with an advanced stage cancer, said Dr. Bevers, Professor of Clinical Cancer Prevention, and Medical Director, Cancer Prevention Center and Prevention Outreach Programs, at The University of Texas MD Anderson Cancer Center.

She added that an often neglected, yet important measurement, is the life years gained. While, as a group women in their 40s show a lower number of deaths averted, they also have the highest number of years of life gained when cancer is found and treated.

With regard to earlier screening for breast cancer, there is controversy surrounding the belief that earlier breast cancer screening leads to overdiagnosis and greater incidence of false positives.

“How do you weigh false positives, overdiagnosis, and anxiety?” asked Ms. Smith.

“False positives mean two things,” said Dr. Oeffinger. The first is a call back for imaging, which typically takes place the same day as mammography. Second, in a smaller percentage of women (6–7%), a core biopsy will be performed, he explained. “While there is anxiety related to having a false positive finding or a biopsy, this remains an understudied area in the U.S.,” Dr. Oeffinger said.

Dr. Bevers explained the importance of differentiation between prevalent false positives (those found on the first mammogram) and incident false positives (those found on subsequent mammograms) in understanding the true incidence of false positives for women in their 40s and women in their 50s. More false positives are found on the initial screening mammogram; this occurs because there are no prior mammograms for comparison to reassure the radiologist that a finding is benign. She went on to explain that the higher incidence of false positive screenings in women in their 40s is due, in part, to the fact that screening typically commences in this decade. 

“If we move the initiation of screening to 50, we will see an increase in prevalent false positives in women in their 50s and a jump in the overall false positive incidence for women in this decade,” she said.

Overdiagnosis is a screen–detected cancer that would not have led to symptomatic breast cancer if undetected by screening, resulting in overtreatment. However, there remains much uncertainty about how common overdiagnosis is, the panel noted.

All things considered, “it comes down to understanding a woman's values and preferences and having a conversation with her physician about whether to start screening earlier,” said Dr. Bibbins–Domingo.

Dr. Bevers agreed that there is some level of overdiagnosis that accompanies earlier screening, but that it's very difficult to quantify, and it doesn't speak to when to start screening or how often, but only whether to screen and when to stop screening.

“Overdiagnosis is a harm of screening that is incurred regardless of the age screening starts or the screening interval as the mammographic finding — be it a calcification or other finding — will not go away unless it is treated,” she noted. “To address the issue of overdiagnosis, we need to know which lesions won't progress,” she added.

The patient population that is most negatively affected by overdiagnosis, said Dr. Bevers, is the older women because of their likelihood for competing comorbidities.

Dr. Bevers argued that harms of screening should be weighed against the harms of not screening, rather than comparing the harms of screening to no harms. Women who do not get screened can incur significant harms, including breast cancers diagnosed at a later stage that require more intensive treatments and are more likely to recur, and they also are more likely to die of their breast cancer than women who get routine screening mammograms, she said. Often the discussion of the harms of screening does not mention the harms of not screening, making it falsely appear that there are no harms associated with not screening, added Dr. Bevers.

Ms. Smith asked the panel to consider the harms of biennial screening — every two years — opposed to annual screening, which is another area of the mammography controversy.

As mentioned earlier, higher rates of screening — at any interval — leads to higher incidence in false positives, said Dr. Bibbins–Domingo. The USPSTF has found that there is a small incremental benefit to screening annually but the harms of annual screening are higher.

Dr. Oeffinger explained that there is a significant difference in the benefits of annual versus biennial screening in premenopausal women compared to postmenopausal women because of tumor biology and the aggressiveness of the disease. But by the time women are postmenopausal — on average after age 55 — biennial screening is effective.

He added that ACS believes it is very important for women to have the opportunity to continue annual screening after age 55 if that is in their best interest based on their personal preferences and values, he added. His fellow panelists agreed.

For NCCN, there were several factors considered in recommending annual screening, said Dr. Bevers. First, there are fewer cancer deaths in the annually screened population than those undergoing biennial screening; second, while there are fewer deaths from breast cancer averted for women in their 40s, their years of life gained are significantly greater, she said. The NCCN Panel strongly felt these benefits far outweighed the possibility of a recall and possible biopsy.

The fact that three groups have different recommendations based on the same data shows there is no consensus on what constitutes a harm and where the benefit/harm threshold lies, Dr. Bevers said.

To address this, a Breast Cancer Screening Consensus Conference was held in Washington, DC in January 2016, to start the process of formulating a consensus statement. The group is working toward a manuscript that will identify points on which all eight participating organizations can agree, as well as detailing where and why they disagree, Dr. Bevers said. These organizations are USPSTF, ACS, NCCN, American College of Radiology, American Academy of Family Physicians, American College of Physicians, American College of Surgeons and American College of Obstetricians and Gynecologists. Stakeholders from more than 22 other women's organizations and patient advocates also attended.

For more coverage of the NCCN 21stAnnual Conference, visit NCCN.org/news.

(NOTE: The recommendations discussed in this panel are specifically for women of average risk for breast cancer. Specific recommendations have been published for women with higher risk due to familial or genetic pre–disposition as well as atypical hyperplasia or lobular carcinoma in situ.)

About the National Comprehensive Cancer Network

The National Comprehensive Cancer Network® (NCCN®), a not–for–profit alliance of 27 of the world's leading cancer centers devoted to patient care, research, and education, is dedicated to improving the quality, effectiveness, and efficiency of cancer care so that patients can live better lives. Through the leadership and expertise of clinical professionals at NCCN Member Institutions, NCCN develops resources that present valuable information to the numerous stakeholders in the health care delivery system. As the arbiter of high–quality cancer care, NCCN promotes the importance of continuous quality improvement and recognizes the significance of creating clinical practice guidelines appropriate for use by patients, clinicians, and other health care decision–makers.

The NCCN Member Institutions are: Fred & Pamela Buffett Cancer Center, Omaha, NE; Case Comprehensive Cancer Center/University Hospitals Seidman Cancer Center and Cleveland Clinic Taussig Cancer Institute, Cleveland, OH; City of Hope Comprehensive Cancer Center, Los Angeles, CA; Dana–Farber/Brigham and Women's Cancer Center | Massachusetts General Hospital Cancer Center, Boston, MA; Duke Cancer Institute, Durham, NC; Fox Chase Cancer Center, Philadelphia, PA; Huntsman Cancer Institute at the University of Utah, Salt Lake City, UT; Fred Hutchinson Cancer Research Center/Seattle Cancer Care Alliance, Seattle, WA; The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD; Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Chicago, IL; Mayo Clinic Cancer Center, Phoenix/Scottsdale, AZ, Jacksonville, FL, and Rochester, MN; Memorial Sloan Kettering Cancer Center, New York, NY; Moffitt Cancer Center, Tampa, FL; The Ohio State University Comprehensive Cancer Center – James Cancer Hospital and Solove Research Institute, Columbus, OH; Roswell Park Cancer Institute, Buffalo, NY; Siteman Cancer Center at Barnes–Jewish Hospital and Washington University School of Medicine, St. Louis, MO; St. Jude Children's Research Hospital/The University of Tennessee Health Science Center, Memphis, TN; Stanford Cancer Institute, Stanford, CA; University of Alabama at Birmingham Comprehensive Cancer Center, Birmingham, AL; UC San Diego Moores Cancer Center, La Jolla, CA; UCSF Helen Diller Family Comprehensive Cancer Center, San Francisco, CA; University of Colorado Cancer Center, Aurora, CO; University of Michigan Comprehensive Cancer Center, Ann Arbor, MI; The University of Texas MD Anderson Cancer Center, Houston, TX; University of Wisconsin Carbone Cancer Center, Madison, WI; Vanderbilt–Ingram Cancer Center, Nashville, TN; and Yale Cancer Center/Smilow Cancer Hospital, New Haven, CT.

Clinicians, visit NCCN.org. Patients and caregivers, visit NCCN.org/patients. Media, visit NCCN.org/news.

[1] “Cancer Facts & Figures 2016.” American Cancer Society. Web. 7 Apr. 2016.

The following files are available for download:

Excellon Reports First Quarter 2016 Production

TORONTO, ON—(Marketwired – April 18, 2016) –
Excellon Resources Inc.
(TSX: EXN)
(OTC: EXLLF)
(“Excellon” or the “Company”), Mexico's highest grade silver producer, is pleased to announce first quarter 2016 production results from the La Platosa Mine in Durango, Mexico.

Q1 2016 Production Highlights (Compared to Q1 and Q4 2015)

  • Silver equivalent (“AgEq”) production of 363,552 ounces (Q1 2015 – 408,095 AgEq oz), up 40% from Q4 2015
  • Silver production of 211,557 ounces (Q1 2015 – 217,079 ounces), up 39% from Q4 2015
  • Lead production of 1.3 million lb (Q1 2015 – 1.3 million lb), up 57% from Q4 2015
  • Zinc production of 1.6 million lb (Q1 2015 – 2.2 million lb), up 26% from Q4 2015
  • Rodilla Manto accessed in late February, seven months ahead of schedule with significant ultra high grade (over 1,000 g/t Ag, 10% Pb and 10% Zn) mineralization encountered outside of Platosa resource block model
  • Phase II of optimization program commencing with primary dewatering well drilling

“In Q1 2016, we again saw the upside potential of Platosa's exceptionally high–grade massive sulphide mantos and began to see further material benefits from our long–term dewatering efforts,” stated Brendan Cahill, President and Chief Executive Officer. “In late February, we accessed the Rodilla Manto, approximately seven months ahead of schedule as we encountered mineralization outside of the Platosa resource block model and dry mining conditions facilitated rapid development. A significant amount of this 'bonus' mineralization was ultra high grade, with approximately 1,600 tonnes of ore produced from Rodilla during March grading over 1,000 g/t Ag, 10% Pb and 10% Zn. This ore was blended with lower grade and low–cost stockpiles to improve mill recoveries and concentrate payability. We are currently developing into the next level of the Rodilla Manto and expect the continuing optimization program at Platosa to deliver further operational improvements as the year progresses.”

Q1 2016 Production Results

    March 2016   Q1 2016   Q1 2015
Tonnes Mined   5,035   12,778   13,920
Tonnes Milled   6,015   14,720   13,828

Grades
           
Silver (g/t)   601   483   533
Lead (%)   6.58   4.80   5.37
Zinc (%)   8.06   6.15   8.83

Recoveries
           
Silver (%)   91.1   91.6   90.5
Lead (%)   86.4   83.6   79.2
Zinc (%)   79.0   79.3   83.7

Metal Production*
           
Silver (oz)   106,643   211,557   217,079
Lead (lb)   755,718   1,318,916   1,252,796
Zinc (lb)   849,805   1,588,778   2,239,313
             
    March 2016   Q1 2016   Q1 2015
AgEq (oz)**   190,557   363,552   408,095

* Subject to adjustment following settlement with concentrate purchaser.

** Silver equivalent ounces established using average metal prices during the period indicated applied to the recovered metal content of concentrates.

Ore production during the first quarter was primarily from the 6A, N1, Guadalupe North and South and Rodilla mantos. In late February 2016, mine operations began accessing ore from the Rodilla Manto, approximately seven months ahead of schedule and at shallower levels than delineated in the resource block model. The Rodilla Manto was significantly below the water table until recently, but mining conditions are now almost entirely dry in this area as ongoing dewatering efforts have lowered water levels below workings and mineralization.

As delineated in the Platosa resource block model, the upper levels of the Rodilla Manto host mineralization grading approximately 800 g/t Ag, 7% Pb and 10% Zn on an undiluted basis. Much of the “bonus” mineralization encountered in Q1 2016 was materially higher grade on a diluted basis, with approximately 1,600 tonnes of ore produced from Rodilla grading in excess of 1,000 g/t Ag, 10% Pb and 10% Zn. Though the deposit is tightly drilled at 15 metre centres, the manto boundaries are generally erratic and additional mineralization is often encountered outside of the resource block model. Additionally, the Company has noted historically that in areas with very high argentiferous–galena content silver and lead grades are underestimated as such mineralization may be washed out and lost during the diamond drilling process.

Approximately 2,300 tonnes of ore milled during the quarter were extracted from historic stockpiles and settling ponds at Platosa at minimal cost with grades of approximately 150 g/t Ag and 1–2% Pb and Zn. High–grade ore produced during the quarter was blended with this lower grade material to improve recoveries and concentrate payability.

As announced on June 2nd and November 2nd, 2015, the Company has developed an optimization program to comprehensively manage water at Platosa through an enhanced pumping system. The second phase of the program, drilling of the primary dewatering wells, is commencing. Further updates on the progress of this program will be provided regularly during the implementation period.

The Company expects to release first quarter financial results prior to market open on May 11, 2016.

About Excellon

Excellon's 100%–owned La Platosa Mine in Durango is Mexico's highest grade silver mine, with lead and zinc by–products making it historically one of the lowest cash cost silver mines in the country. The Company is positioning itself to capitalize on undervalued projects by focusing on increasing La Platosa's profitable silver production and near–term mineable resources.

Additional details on the La Platosa Mine and the rest of Excellon's exploration properties are available at www.excellonresources.com.

Forward–Looking Statements

The Toronto Stock Exchange has not reviewed and does not accept responsibility for the adequacy or accuracy of the content of this Press Release, which has been prepared by management. This press release contains forward–looking statements within the meaning of Section 27A of the Securities Act and Section 27E of the Exchange Act. Such statements include, without limitation, statements regarding the future results of operations, performance and achievements of the Company, including potential property acquisitions, the timing, content, cost and results of proposed work programs, the discovery and delineation of mineral deposits/resources/reserves, geological interpretations, proposed production rates, potential mineral recovery processes and rates, business and financing plans, business trends and future operating revenues. Although the Company believes that such statements are reasonable, it can give no assurance that such expectations will prove to be correct. Forward–looking statements are typically identified by words such as: believe, expect, anticipate, intend, estimate, postulate and similar expressions, or are those, which, by their nature, refer to future events. The Company cautions investors that any forward–looking statements by the Company are not guarantees of future results or performance, and that actual results may differ materially from those in forward looking statements as a result of various factors, including, but not limited to, variations in the nature, quality and quantity of any mineral deposits that may be located, significant downward variations in the market price of any minerals produced [particularly silver], the Company's inability to obtain any necessary permits, consents or authorizations required for its activities, to produce minerals from its properties successfully or profitably, to continue its projected growth, to raise the necessary capital or to be fully able to implement its business strategies. All of the Company's public disclosure filings may be accessed via www.sedar.com and readers are urged to review these materials, including the technical reports filed with respect to the Company's mineral properties, and particularly the July 9, 2015 NI 43–101–compliant technical report prepared by Roscoe Postle Associates Inc. with respect to the Platosa Property. This press release is not, and is not to be construed in any way as, an offer to buy or sell securities in the United States.

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