Significant Improvement in Regional Recurrence in Young Patients with Breast Cancer Treated with Comprehensive Nodal Irradiation

Abstract

Materials/Methods: Clinicopathologic data from 438 patients with early breast cancer (clinical stage: 20 T1N0, 124 T2N0, 60 T1N1, 234 T2N1) who received NeoChemo and Mastx from 1985 to 2004 were retrospectively reviewed. In this cohort, 257 (58.7%) patients received adjuvant radiation (RT) while 181 (41.3%) patients did not. The median number of axillary lymph nodes (LN) dissected was 15. The number of pathologically involved lymph nodes (pLN+) was zero pLN+ in 33.8% of patients, 1-3 pLN+ in 42.2%, and $4 pLN+ in 24%. For clinical N0 (cN0) patients, 47.2% had $1 pLN+ after NeoChemo. For cN1 patients, 24.5%had0pLN+afterNeoChemo.ActuarialrateswerecalculatedusingKaplan-Meiermethodandcomparedusinglog-ranktest. Results: With a median follow-up of 66.3 months, there were 17 LRR in the 438 patients. The 5-year local-regional control (5-yr LRC) and overall survival was 96.1% and 87.7%, respectively. Overall, the patients who received RT had worse tumor features includinghigherproportionsofcN1,LVSI,and $4pLN+comparedtothosewithnoRT(allp\0.003,chi-square).The5-yrLRCfor patientswithnoRTwas96.6%andwithRTwas95.7%(p=0.55).Amongthe80T1/T2patientswithcN1whodidnotreceivepostmastectomy RT, the 5-yr LRC was 100% for those who converted to 0 pLN+, 95.3% for those with 1-3 pLN+,and 75.0% for those with $4pLN+(p= 0.049).Inthetotalcohortofpatientswhodidnotreceive RT(n= 181),thosewithpathologically $4pLN+had the worst 5-yr LRC (0 pLN+ 99.0%, 1-3 pLN+ 94.6%, $4 pLN+ 80.0%, p = 0.034). The presence of lymphovascular invasion (LVSI)wasalsoassociatedwithworse5-yrLRC(LVSI98.0%vs+LVSI84.6%,p=0.006).Patientswith $4pLN+whoreceived RThadanon-statisticalimprovementin5-yrLRCcomparedtothosewithnoRT(NoRT80.0%vs+RT95.5%,p=0.12).Asimilar trend for improved 5-yr LRC was observed for patients with LVSI who received RT (No RT 84.6% vs +RT 97.7%, p = 0.074). Conclusions: Patients with clinical stage T1-2/N0-N1 breast cancer appear to have low risks of recurrence after neoadjuvant chemotherapy and mastectomy, with the exception of those with +LVSI or $4 pLN+. These data warrant a prospective clinical trial to more formally test whether radiation can be avoided in selected patients with stage II breast cancer treated with NeoChemo and Mastx.