Adoption of research findings in clinical practice tends to evolve over time and can be highly variable. Contrary to this traditionally slow pace, the American College of Surgeons Oncology Group’s Z0011 trial has seemingly changed practice overnight.
The Z0011 study examined the survival impact of axillary lymph node dissection in breast cancer patients with sentinel lymph node metastasis. Axillary lymph node dissection has long been the standard of care for women with breast cancer who have a positive sentinel lymph node biopsy. In the Z0011 trial, women with 1 or 2 positive sentinel lymph node biopsies had the same outcome with or without axillary lymph node dissection. This means that women who are diagnosed with stage T1 or T2 invasive breast cancer no longer need to have their axillary lymph nodes removed.
The phase III trial followed 891 women who underwent lumpectomy, whole-breast radiation, and sentinel lymph node dissection that confirmed metastasis. Patient accrual took place between 1999 and 2004, and trials were conducted at 115 centers across the United States. Trial enrollment was halted early in 2004 when it was determined that accrual of more women in the study would not alter the survival findings, and final follow-up for data analysis was completed in 2010. The results were presented in June 2010 at the American Society of Clinical Oncology Annual Meeting in Chicago, Illinois, and were published this past February in the Journal of the American Medical Association.
The study randomized women to either axillary lymph node dissection (n = 445) or sentinel lymph node dissection alone (n = 446), with adjuvant chemotherapy being administered at the discretion of the treating physician. Patients in the axillary lymph node dissection cohort had a median of 17 lymph nodes removed compared with 2 for women randomized to sentinel lymph node dissection alone.
The results were nearly identical for the 2 cohorts, with 5-year overall survival rates of 91.8% for the women who had axillary lymph node dissection and 92.5% for the women who had sentinel lymph node dissection alone. Five-year disease-free survival rates also showed no significant difference. Patients were followed for a median of 6.3 years.
The researchers noted that forgoing the standard practice of axillary lymph node dissection when sentinel nodes are positive for metastasis constitutes a practice change that could potentially improve the clinical outcomes in thousands of women each year by reducing the complications associated with axillary lymph node dissection. As oncology nurses, we’re familiar with those potential complications—infection, sensory changes, and lymphedema. And even if a complication does not occur, women who have had axillary lymph node dissection need to avoid having their blood pressures taken and IVs started in the arm on the side of the dissection. I would also think that not needing axillary lymph node dissection would allow women to preserve the veins in both of their arms, which may reduce the need for central line catheter or implanted port insertion for chemotherapy.
If you’ve been in practice for a long time, you probably remember the days of caring for women who had radical mastectomies. Then there was a period of time when modified radical mastectomies became the standard of care, and now, breast-conserving lumpectomies are the standard of care. Axillary lymph node dissection has been around a long time, and it is astounding to learn that it may no longer be needed in women with stage T1 and T2 invasive breast cancer. The National Comprehensive Cancer Network’s updated 2011 Guidelines in Breast Cancer now even reference the results of the Z0011 study in a footnote to an invasive breast cancer treatment algorithm. T he Z0011 trial appears to be changing breast cancer treatment virtually overnight.
Giuliano AE, Hunt KK, Ballman KV, et al. Axillary dissection vs no axillary dissection in women with invasive breast cancer and sentinel node metastasis. A randomized clinical trial. JAMA. 2011;305(6):569-575.