The role of postmastectomy radiotherapy in different molecular subtypes of breast cancer patients with T1 - T2 and one to three positive axillary nodes / 中华放射肿瘤学杂志

ABSTRACT

ObjectiveTo analyze the role of postmastectomy radiotherapy in different molecular subtypes of breast cancer patients with Stage T1 -T2 and one to three positive axillary nodes. MethodsA total of 436 breast cancer patients with T1 -T2 and one to three positive axillary lymph nodes treated with mastectomy and axillary dissection were retrospectively analyzed. Patients were grouped as the following four subtypesLuminal A, Luminal B, Her2+ and triple-negative. The local recurrence (LR), distant metastasis ( DM ), disease free survival (DFS) and overall survival (OS) rates were compared between paitents with or without radiotherapy in univariate analyses. Multivariate analyses for LR were performed. Results The follow-up rate was 86. 0％. In patients with Luminal A subtype, radiotherapy decreased the 5-year LR rate (4.6％ vs 15.8％ ,x2 =5.74,P=0.017) but had no influences on DM, DFS or OS rates (17.2％ vs 19.7％,x2 =0. 17,P=0.682;77.0％ vs 67. 1％ ,x2 =1.99,P=0. 158 or87.4％85. 5％ ,x2 =0. 12,P=0. 733 ). In patients with Luminal B subtype, radiotherapy decreased the 5-year LR rate (3.7％ vs 12. 1％,x2 =4. 13, P =0. 042), increased DFS and OS ( 84. 0％ vs 57.6％ ( x2 =14.61, P =0. 000) and 91.4％ vs 70. 7％ ( x2 =11.87, P =0. 001 ), but had no influence on DM ( 12. 3％ vs 22. 2％, x2 =2. 97, P =0. 085).In patients with Her2+ subtype, radiotherapy decreased the 5-year LR rate (5. 6％ vs 31.0％ ,x2 =4. 31,P=0. 035) , increased DFS (61. 1％ vs 13. 8％ ,x2 =11.44,P=0.001 ) ,but had no influence on DM and OS (27.8％ vs 41.4％, x2 =0. 89, P =0. 345 and 66. 7％ vs 48. 3％, x2 =1.52,P =0. 218 ). In patients with triple-negative subtype, radiotherapy had no influence in LR, DM, DFS or OS (8. 7％ vs 26. 1％ ,x2 =2.42,P=0.120;39.1％ vs47.8％,x2=0.35,P=0.552;52.2％ vs 26.1％ , x2 =3. 29, P =0. 070 or 65.2％ vs 56. 5％ ,x2 =0. 37 ,P =0. 546). Tumor size and radiotherapy were independent prognostic factors for LR rate in multivariate analyses ( x2 =4. 76, P =0. 029 and x2 =8.06, P =0. 005 ). ConclusionsFor patients with stage T1 -T2 and one to three positive axillary nodes, patients with all molecular subtypes except triple-negative can benefit from postmasteetomy radiotherapy.