Breast conservation therapy is usually best for local treatment for stage II breast cancer-and biology, as well as stage, drives patient outcomes.
Breast conservation therapy (BCT) is usually best for local treatment for stage II breast cancer-and biology, as well as stage, drives patient outcomes, Thomas A. Buchholz, MD, of the University of Texas MD Anderson Cancer Center in Houston, said at the 34th Annual Miami Breast Cancer Conference, held March 9–12 in Miami Beach, Florida.
“In both high-risk and low-risk settings, BCT is the preferred local treatment for stage II disease,” said Buchholz “I think stage II disease is the most dynamic area of breast cancer-it is the one area that’s really changed over time.”
Positive lymph nodes are “one of the most powerful prognostic variables in breast cancer,” he said-understandably leading patients to seek radical surgical interventions like mastectomy. But clinical trial experience shows that survival outcomes following BCT and whole-breast irradiation are similar to those following mastectomy for patients with stage I or stage II breast cancer.
“T1, 2N1, stage II disease has changed over time,” Buchholz said, noting that improved levels of awareness and mammographic screening have led to more patients being diagnosed with stage II disease without clinical nodal involvement.
Nodal involvement is also more likely to be detected when it is present, he noted. Preoperative ultrasonographic axilla assessments have also improved sensitivity and specificity, and serial sectioning of nodes are better at detecting small metastases than standard nodal bifurcation. Serial section has yielded an increased detection of node positivity by 10% to 33%.
“The more we search, the more we find,” he said. “Multiple levels of sections allow a better measurement of micromets.”
New therapies for stage II breast cancer have included improved systemic therapies like prolonged hormonal therapy and dose-dense chemotherapy, Buchholz noted. Neoadjuvant systemic therapies are now in wider use. Improved surgery has led to less reliance on axillary lymph node dissection and regional lymph node irradiation might improve disease-free survival (DFS) in patients with up to three positive lymph nodes, he said.
Sentinel lymph node (SLN) surgery has rendered stage II breast cancer-pN1 with 1–3 positive nodes-a “more heterogeneous” disease, Buchholz said. “For example, a patient with solitary micrometastasis found on serial sectioning of a SLN has a better prognosis than a patient with cN1 disease who has multiple, grossly evident lymph node metastases.”
BCT “remains the preferred approach” for stage II disease in either case, he emphasized.
For higher-risk stage II breast cancer, research suggests that regional lymph node irradiation can improve DFS. “Therefore, radiation should play a role as adjuvant therapy after either BCT or mastectomy.”
For BCT, adding regional radiotherapy is simply a matter of adding more fields and does not increase inconvenience or costs for patients, he said. But for mastectomy, radiotherapy can be a “huge deal,” involving “big changes” for patients, and significant costs.
Mastectomy followed by radiotherapy has important cost and complication risk concerns for reconstruction, he said. Patient satisfaction with breast reconstruction outcomes are higher for autologous reconstruction (with or without radiotherapy) and implant reconstruction without radiation, than for implant and radiation, he noted.
Management of stage II breast cancer is also changing with improved appreciation for the importance of tumor biology, Buchholz noted.
For example, postmastectomy radiotherapy is associated with improved overall survival in patients with hormone receptor-positive and human epidermal growth factor receptor 2-negative disease.
“It’s not just about anatomic stage, anymore-it’s also biology,” he said. “We should not think of stage II disease as one entity. It really represents a spectrum of disease. The biology is very diverse.”