ORLANDO, FL-Absolute rates of local breast cancer recurrence in women who undergo lumpectomy have sharply declined as a result of multimodality treatment and personalized oncology, a researcher noted at the American Society of Breast Surgeons (ASBrS) Annual Meeting.
Advances in multimodality lumpectomy treatment have resulted in historically low recurrence rates at the original tumor site over 5 years, according to Heather Neuman, MD, FACS, Associate Professor of the University of Wisconsin School of Medicine and Public Health, Madison.
Overall, the study found a 4.2 percent local recurrence rate for women who had breast-conserving surgery and modern era chemotherapy or other systemic therapies, along with radiation treatment-more than half the historic rate.
"This compares with the generally accepted figure of about 5-10 percent for lumpectomy recurrence, which is typically based on older treatment protocols," said Neuman, noting that the rate was even lower for some tumor types.
She and her colleagues examined data on more than 6,900 women with stage I or II breast cancer, in nine clinical trials over 14 years, who underwent breast-conserving surgery between 1997 and 2011.
"While survival rates are equal, lumpectomy traditionally carries a greater risk of local recurrence than mastectomy, and many women face a difficult trade-off when making treatment decisions. This more positive, contemporary data may make their choice a little easier," Neuman told a press briefing.
Study Methods
The researchers examined recurrence rates in clinical trials conducted by the Alliance for Clinical Trials in Oncology, and compared age, tumor size, lymph node status, and molecular tumor subtype. They found that over the last decade, breast cancer therapies have become more effective and personalized, but data on recurrence is rare because of the difficulty of tracking women over time.
Among the 6,000 women, recurrence was lowest among ER/PR+ HER2/neu+ cancers (3%), followed by ER/PR- HER2/neu+ (4.7%) disease. The highest rate was for ER/PR- HER2/neu- cells (6.9%).
Noting that the molecular characteristics of breast tumors can widely differ, this information is very important in helping better understand the course and treatment of the disease, including whether a cancer is likely to return, she noted. "Because of the challenges in obtaining data, this is perhaps the only study to examine the relationship of recurrence and receptor subtype in the era of modern breast cancer therapy."
In addition to greater surgical precision, advances in breast conservation therapies also include more effective radiation therapy and chemotherapy, often optimized for a patient's specific tumor characteristics. This targeted therapy has probably had the greatest impact in preventing recurrence, she said. In addition, specialized drug therapies targeting more aggressive HER2+ cancers have significantly improved outcomes and minimized tumor recurrences.
In terms of tumor size, 57 percent were 0-2 cm; 39 percent were 3-5 cm; and 3.4 percent for larger tumors. In all, 71.5 percent of nodes were negative; 22.4 percent were 0-3+; and 6.1 percent were greater than 3+.
"Clearly this new data shows that recurrence with breast conservation has diminished significantly overall," Neuman stated. "Additionally, in today's age of multimodality, personalized breast cancer therapy stratifying recurrence risk by cancer subtypes helps women and their physicians make more informed decisions. This study absolutely has added important new information to my conversations with patients about the relative risks and benefits of lumpectomy and mastectomy."
Commentary
"By analyzing a large group of patients treated in the modern era, this study provides physicians with more current information to provide patients regarding local recurrence rates following breast-conserving therapy," said Carla Fisher, MD, Associate Professor and Director of Surgical Oncology, Indiana University School of Medicine, Indianapolis.
"These findings, along with the recent changes in the American Joint Committee on Cancer Staging, further emphasize the importance of biologic factors in patient outcomes. Additionally, the study provides support for patients choosing breast-conserving therapy who are treated with modern, multimodal therapy."
Kurt Samson is a contributing writer.