- The Early Breast Cancer Trialists’ Collaborative Group (EBCTCG) meta-analysis:
- Found that for patients undergoing breast-conserving surgery for node-negative breast cancer:
- Radiation reduced the risk of any recurrence:
- 16% vs. 31%
- Radiation reduced breast cancer mortality:
- 17% vs. 21%
- Radiation reduced the risk of any recurrence:
- Found that for patients undergoing breast-conserving surgery for node-negative breast cancer:
- The EBCTCG:
- Also found that for patients undergoing mastectomy with 1 to 3 nodes positive:
- Radiotherapy was associated with:
- A reduction in local-regional recurrence (LRR):
- 4% vs. 20%
- A reduction in breast cancer mortality:
- 42% vs. 50%
- A reduction in local-regional recurrence (LRR):
- Radiotherapy was associated with:
- Many practitioners interpreted these findings to mean that all postmastectomy patients with 1 to 3 positive nodes should have postmastectomy radiation therapy (PMRT):
- However, the patients enrolled in those trials were enrolled between 1964 and 1986, and many of them did not receive systemic therapy
- A retrospective study of patients with 1 to 3 positive nodes compared the risk of LRR between the two different eras, before and after the routine use of sentinel node biopsy, taxane therapy, and aromatase inhibitors:
- Use of PMRT reduced the 15-year rate of LRR in the first era:
- From 14.5% to 6.1%
- PMRT did not appear to benefit patients treated in the second era:
- With 5-year LRR rates of 2.8% without PMRT, and 4.2% with PMRT
- Use of PMRT reduced the 15-year rate of LRR in the first era:
- In view of the fact that PMRT significantly increased overall mortality in node-negative patients in the EBCTCG:
- 47.6% vs, 41.6%; rate ratio 1.23:
- Caution should be taken in extrapolating the results to all patients with 1 to 3 positive nodes in the modern era
- 47.6% vs, 41.6%; rate ratio 1.23:
- Also found that for patients undergoing mastectomy with 1 to 3 nodes positive:
- The consensus statement regarding the role of PMRT in women with 1 to 3 positive lymph nodes:
- ASCO / ASRTO / SSO unanimously agreed that PMRT in this subset of patients reduces local-regional failure, any recurrence, and breast cancer mortality:
- In patients with T1 to T2 breast cancer with 1 to 3 positive lymph nodes in the setting of multidisciplinary care
- In some subsets of patients, the risk of local-regional failure may be so low that the absolute benefit of PMRT is outweighed by its toxicities, even if axillary lymph node dissection is omitted in the setting of a positive lymph node
- ASCO / ASRTO / SSO unanimously agreed that PMRT in this subset of patients reduces local-regional failure, any recurrence, and breast cancer mortality:
- When given, PMRT should include the internal mammary, supraclavicular, and apical axillary nodes and the chest wall or reconstructed breast
- All patients with a positive axillary node after receipt of neoadjuvant chemotherapy:
- Should receive PMRT
- Following mastectomy, patients with DCIS generally do not require radiotherapy:
- Childs et al. showed infrequent chest wall recurrences:
- Crude rates of chest wall recurrence was 1.4% for all patients, even though 15% had positive margins, and 16% had close margins (less than 2 mm) in the analysis
- Crude rate of chest wall recurrence for patients with positive margins and close margins was 4.8% and 4.3%, respectively
- Crude rates of chest wall recurrence was 1.4% for all patients, even though 15% had positive margins, and 16% had close margins (less than 2 mm) in the analysis
- Childs et al. showed infrequent chest wall recurrences:
- In the setting of breast-conserving surgery, observation after lumpectomy for DCIS may be appropriate in select settings:
- There is a higher risk of ipsilateral breast event without breast RT:
- As RT decreases the recurrence by roughly 50%
- RTOG 9804:
- Is a prospective randomized trial consisting of women with mammographically detected “good risk” DCIS with low- or intermediate-grade DCIS, less than 2.5 cm with margins greater than 3mm
- They were randomized to RT versus observation after surgery
- With median followup at 7 years:
- The local failure rate was 1% in the RT arm versus 7% in the observation arm suggesting a subset of patients with a small volume of DCIS could be observed given the low failure rates
- There is a higher risk of ipsilateral breast event without breast RT:
- Currently, three prospective randomized clinical trials in the US and UK are evaluating the safety of omitting radiation in highly selected DCIS patients
- References
- Early Breast Cancer Trialists’ Collaborative Group, McGale P, Taylor C, Correa C. Effect of radiotherapy after mastectomy on 10-year recurrence and 20-year breast cancer mortality: meta-analysis of individual patient data for 8135 women in 22 randomised trials. Lancet. 2014;383(9935):2127-2135.
- McBride A, Allen P, Woodward W, et al. Locoregional recurrence risk for patients with T1,2 breast cancer with 1-3 positive lymph nodes treated with mastectomy and systemic treatment. Int J Radiat Oncol Biol Phys. 2014;89(2):392-398.
- Recht A, Comen EA, Fine RE, et al. Postmastectomy radiotherapy: an American Society of Clinical Oncology, American Society for Radiation Oncology, and Society of Surgical Oncology focused guideline update. Ann Surg Oncol. 2017; 24(1):38-51.
- Childs SK, Chen YH, Duggan MM, et al. Impact of margin status on local recurrence after mastectomy for ductal carcinoma in situ. Int J Radiat Oncol Biol Phys.2013;85(4):948-952.
- McCormick B, Winter K, Hudis C, et al. RTOG 9804: a prospective randomized trial for good-risk ductal carcinoma in situ comparing radiotherapy with observation. J Clin Oncol. 2015;33(7):709-715.
Rodrigo Arrangoiz MS, MD, FACS, FSSO 