Breast cancer is a type of cancer that develops from breast cells. This type of cancer usually starts off in the inner edge of milk ducts or the lobules that supply them with milk. A malignant tumor can spread to other parts of the body.
A breast cancer that started off in the lobules is known as lobular carcinoma, while one that developed from the ducts is called ductal carcinoma.
Breast cancer is the most common invasive cancer in females worldwide. It cause for 16% of all female cancers and 22.9% of invasive cancers in women.18.2% of all cancer deaths worldwide, including both males and females, are from breast cancer. Breast cancer rates are much higher in developed nations compared to developing ones.
Three prime national cancer organizations today fixed a consensus guideline for physicians treating women who have ductal carcinoma in situ (DCIS) treated with breast-conserving surgery with total breast irradiation. The new guideline has the potential to save many women from unnecessary surgeries while reducing costs to the healthcare system.
The National Cancer Institute of USA suggests that in 2016 an estimated 246,660 new cases of breast cancer are expected to be identified in United States women, and more than 40,450 American women will die from breast cancer in 2016.
Presently three main national cancer organizations in the USA -- the Society of Surgical Oncology (SSO), the American Society for Radiation Oncology (ASTRO)and the American Society of Clinical Oncology (ASCO) - together published the new instruction of breast surgery in their respective journals, the Annals of Surgical Oncology, Practical Radiation Oncology and the Journal of Clinical Oncology.
Determining whether breast cancer has spread to sentinel lymph nodes (SLN) is the key to prognosis and treatment,making SLN mapping critical. The blue dyes commonly used to identify SLNs spread quickly to other nodes and is poorly retained by the SLNs (less than five minutes). This requires the surgeon to identify SLNs quickly. Allergic reaction to the dyes has also been a concern. ‘A new SLN radio tracer, Tc-99m-rituximab, which is well retained by sentinel lymph nodes (SLNs), has been demonstrated as safe and effective.’
The researchers said, "The use of a two millimeter margin as the standard for an adequate margin in DCIS treated with whole breast radiation therapy (WBRT)is associated with low rates of recurrence of cancer in the breast and has the potential to decrease re-excision rates, improve cosmetic outcome, and decrease health care costs. Clinical judgment should be used in determining the need for further surgery in patients with negative margins less than two millimeters.Margins more widely clear than two millimeters do not further reduce the rates of recurrence of cancer in the breast and their routine use is not supported by evidence."
Supported by a grant from Susan G. Komen, SSO spearheaded the guideline initiative and established a panel of experts from the three organizations, including clinicians,researchers and a patient advocate to create the new guideline to provide clarity regarding the optimal negative margin width for ductal carcinoma in situ.
Gain to determine the margin width, a pathologist paints the outer surface of the tissue that's been removed with ink. A clear,negative, or clean margin means there are no cancer cells at the outer inked edge of tissue that was removed, while a positive margin means that cancer cells extend to the inked tissue. A 2010 survey found that 42 percent of surgeons recommended a two millimeter margin, while 48 percent favored larger margins.
At present, approximately one in three women who are treated surgically for DCIS undergo a re-excision, due in part to the lack of consensus on what constitutes an adequate negative margin. Re-excisions have the potential for added discomfort,surgical complications and compromise in cosmetic outcome, additional stress for patients and families, and increased health care costs. They have also been associated with patients choosing to have double mastectomies.
"An important finding from the review of the published literature performed to provide evidence for this guideline is that margin widths greater than two millimeters (approximately 1/8th of an inch) don't reduce the risk of cancer recurring in the breast in women with DCIS who're treated with lumpectomy and whole breast radiation therapy," said Monica Morrow, MD, past SSO President and panel co-chair, Memorial Sloan Kettering Cancer Center, Breast Service, Department of Surgery.
The team established by SSO, ASTRO and ASCO to establish the consensus guideline relied on a review examining the relationship between margin width and cancer recurrence in the breast that included 30 studies involving 7,883patients, as well as other studies relevant to this topic.
"With this guideline, it is our two-pronged goal to help physicians improve the quality of care they provide to women undergoing surgery for DCIS and ultimately improve outcomes for those patients. We hope the guideline also translates into peace of mind for women who will know that future surgeries may not be needed," said Mariana Chavez-Mac Gregor, MD, University of Texas MD Anderson Cancer Center and panel member representing ASCO.
Dr. Morrow advised that if a woman with a negative margin is told to have a re-excision, she needs to inquire what factors are prompting the surgeon to recommend that re-excision.
Bruce G. Haffty, MD, immediate past chair of ASTRO's Board of Directors, said this new guideline builds on previously published standards and will benefit clinicians who have struggled with margin width in women with DCIS. "This important cooperative guideline generated by these societies involved a multidisciplinary panel of surgical, medical and radiation oncologists, as well as pathologists and statistical experts. While the guideline appropriately allows for some flexibility and clinical judgment in interpretation, the conclusion that a two millimeter margin width is adequate in patients with DCIS will be helpful and reassuring to clinicians and patients in clinical decision-making."
"This guideline is another important step in our collective work to ensure that women are receiving the best and most appropriate breast cancer care," said Susan G. Komen President and CEO Judy Salerno, MD, MS."We were pleased to support the panel, both through funding and by lending the patient perspective to these discussions, and hope it empowers both patients and physicians to make well-informed treatment decisions that will reduce the likelihood for re-excisions.”
This study was conducted by the panel co-chaired by Dr. Morrow and ASTRO representative Meena S. Moran, MD, Department of Therapeutic Radiology, Yale School of Medicine, Yale University. This guideline has also been endorsed by the American Society of Breast Surgeons.