International journal of radiation oncology, biology, physics 2005-07-15
Locoregional recurrence rates and prognostic factors for failure in node-negative patients treated with mastectomy: implications for postmastectomy radiation.
Abstract
Purpose
Postmastectomy radiation therapy (PMRT) reduces locoregional recurrence (LRR) of breast cancer. Survival appears improved in patients at higher risk for LRR. This study addresses whether subsets of node-negative patients with sufficiently high risk of LRR might benefit from PMRT.
Methods
Retrospective analysis of a cohort of 877 cases of node-negative breast cancer treated with mastectomy, without adjuvant radiation, from 1980 to 2000.
Results
Median follow-up was 100 months. Ten-year cumulative incidence of LRR as first event was 6.0%. Size greater than 2 cm, margin less than 2 mm, premenopausal status, and lymphovascular invasion (LVI) were independently significant prognostic factors. Ten-year LRR was 1.2% for those with 0 risk factors, 10.0% for those with 1 risk factor, 17.9% for those with 2 risk factors, and 40.6% for those with 3 risk factors. The chest wall was the site of failure in 80% of patients.
Conclusion
Postmastectomy radiation therapy has not been recommended for node-negative patients because the LRR rate is low in that population overall. This study suggests, however, that node-negative patients with multiple risk factors, including close margins, T2 or larger tumors, premenopausal status, and LVI, are at higher risk for LRR and might benefit from PMRT. Because the chest wall is the most common site of failure, treating the chest wall alone in these patients to minimize toxicity is reasonable.
Related Questions
Would you offer RNI for young patient with cT3N0 triple negative breast cancer that had progression of disease during neoadjuvant chemotherapy, followed by mastectomy and sentinel node biopsy?
Yes, without hesitation. The primary randomized data suggesting an improvement in overall survival (OS) with PMRT in the T3N0 setting included RNI (e.g. Overgaard et al., PMID 9395428). There is also a study of +/- PMRT (including regional nodes) in T3 patients (about 40% of which were T3N0), that a...
Would you recommend PMRT for a patient with a right breast mastectomy with closest margin less than 0.1cm?
I would consider this if there were other high risk factors like T2 disease, high grade or LVSI. In absence of these factors, favor systemic treatment alone. Here is one reference.
Would you give PMRT to a young woman with a T1-2 breast cancer with a micromet on SLNB?
No great data as far as I know. In general, I treat micromets as ~pN0. @Dr. First Last and colleagues reported on LRR rates and prognostic factors for failure in pN0 patients treated with mastectomy to identify subsets of node-negative patients with sufficiently high risk of LRR who might benefit fr...