Stage 1 breast cancer treatment
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Stage 1 Breast Cancer Treatment: Current Research Insights
Introduction to Stage 1 Breast Cancer Treatment
Stage 1 breast cancer, characterized by small tumors confined to the breast with no lymph node involvement, represents approximately 50% of newly diagnosed breast cancer cases. The majority of these cases are hormone receptor-positive (HR+), HER2-negative (HER2-), which significantly influences treatment strategies .
Breast-Conserving Surgery (BCS) and Radiation Therapy (RT)
De-escalation of Breast Radiation (DEBRA) Trials
Recent research has focused on the potential to de-escalate radiation therapy following breast-conserving surgery (BCS) in patients with stage 1 breast cancer. The DEBRA trials (NRG-BR007) hypothesize that BCS alone, followed by endocrine therapy, may be non-inferior to BCS plus radiation therapy (RT) in terms of in-breast recurrence (IBR) and breast preservation . These trials stratify patients by age, tumor size, and Oncotype DX Recurrence Score (RS), aiming to identify those who might safely omit RT without compromising outcomes .
Whole Breast Irradiation (WBI) vs. Partial Breast Irradiation (PBI)
Another significant study, the NSABP B-39/RTOG 0413 trial, compares whole breast irradiation (WBI) with partial breast irradiation (PBI) in patients with stage 0, 1, or 2 breast cancer. This trial investigates whether PBI, which targets only the tumor bed and can be completed in a shorter timeframe, offers similar outcomes to WBI in terms of in-breast tumor recurrence (IBTR) and overall survival. Preliminary data suggest that PBI may be a viable alternative, potentially reducing treatment burden and improving quality of life.
Long-term Outcomes of Radiation Boost
A 20-year follow-up study on the use of a radiation boost after WBI in early-stage breast cancer patients found that while a radiation boost improved local control, it did not significantly affect long-term overall survival. The study highlighted that the additional radiation dose could be avoided in most patients older than 60 years to reduce the risk of severe fibrosis.
Endocrine Therapy and Chemotherapy
Endocrine Therapy Alone
For HR+ and HER2- stage 1 breast cancer, endocrine therapy remains a cornerstone of treatment. The DEBRA trials emphasize the use of endocrine therapy (tamoxifen or aromatase inhibitors) for at least five years, whether or not RT is included . This approach aims to reduce the risk of recurrence while minimizing treatment-related toxicity.
Addition of S-1 to Endocrine Therapy
A phase 3 trial explored the addition of the oral fluoropyrimidine S-1 to standard endocrine therapy in patients with ER-positive, HER2-negative primary breast cancer. The study found that combining S-1 with endocrine therapy significantly improved invasive disease-free survival compared to endocrine therapy alone, suggesting a potential new treatment option for intermediate to high-risk patients.
Conclusion
Current research in stage 1 breast cancer treatment is increasingly focused on de-escalating therapy to minimize toxicity while maintaining efficacy. The DEBRA trials and other studies are exploring the potential to safely omit radiation therapy in certain low-risk patients, while alternative radiation strategies like PBI offer promising results. Additionally, the combination of endocrine therapy with agents like S-1 may provide enhanced disease control for higher-risk patients. These advancements aim to tailor treatment more precisely to individual patient risk profiles, improving outcomes and quality of life.
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