Post-mastectomy radiation tends to be overused in the USA. For example, women who have stage I or II disease with spread to no more than three lymph nodes and who did not undergo radiation therapy, have the overall locoregional recurrence rate of just 2.3% at 10 years. A 2005 meta-analysis looked at randomized trials conducted between 1964 and 1984. The analysis determined that postmastectomy radiation in these women resulted not only in about a 66% reduction in locoregional recurrence compared with no radiation, but also about a 5% survival advantage. However, the overall recurrence rate in those studies ranged from 20% to 25%, much higher than observed in the present.
Certainly, locoregional PMRT is recommended for women with an advanced primary tumour (tumour size 5 cm or greater, or tumour invasion of the skin, pectoral muscle or chest wall) or with 4 or more positive axillary lymph nodes. However, the role of PMRT in women with 1 to 3 positive axillary lymph nodes is unclear. Locoregional PMRT is generally not recommended for women who have tumours that are less than 5 cm in diameter and who have negative axillary nodes. Other patient, tumour and treatment characteristics, including age, histologic grade, lymphovascular invasion, hormone receptor status, number of axillary nodes removed, axillary extracapsular extension and surgical margin status, may affect locoregional control, but their use in specifying additional indications for PMRT is currently unclear.
Pauline T. Truong,Clinical practice guidelines for the care and treatment of breast cancer: 16. Locoregional post-mastectomy radiotherapy CMAJ April 13, 2004 vol. 170 no. 8
Sharma R, et al “Present day locoregional recurrence rates (LRR) in patients with T1 and T2 breast cancer (BC) with zero and one to three lymph node (LN) metastases following mastectomy without radiation” SSO 2010; Abstract 47
Taylor ME, Haffty BG, Rabinovitch R, Arthur DW, Halberg FE, Strom EA, White JR, Cobleigh MA, Edge SB, Expert Panel on Radiation Oncology-Breast. ACR Appropriateness Criteria® postmastectomy radiotherapy. [online publication]. Reston (VA): American College of Radiology (ACR); 2008. 17 p. [96 references]
Postmastectomy Radiotherapy: Clinical Practice Guidelines of the American Society of Clinical OncologyJournal of Clinical Oncology, Vol 19, Issue 5 (March), 2001: 1539-1569
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