Courdi Adel, Chamorey Emmanuel, Ferrero Jean-Marc, Hannoun-Lévi Jean-Michel
Radiotherapy Department, Centre Antoine-Lacassagne, Nice, France.
Radiother Oncol. 2013 Aug;108(2):259-65. doi: 10.1016/j.radonc.2013.06.028. Epub 2013 Jul 25.
There is no general consensus concerning irradiation (RT) of internal mammary nodes (IMN) in axillary node-negative breast cancer. Based on a large series of patients treated in a single institute and followed up for a long period of time, we looked at the influence of IMN RT on late outcome of these patients as well as the development of contralateral breast cancer (CBC).
The study was based on 1630 node-negative breast cancer patients treated in our institution between 1975 and 2008 with primary conservative surgery and axillary dissection or sentinel node examination. All patients received post-operative breast RT. IMN RT was more frequent in inner or central tumours. Kaplan-Meier (K-M) overall survival (OS), cancer-specific survival (CSS), and disease-free survival (DFS) according to IMN RT were calculated for all patients and for patients with inner/central tumours. The K-M rate of contralateral breast cancer (CBC) was also analysed and correlated with IMN RT.
Prognostic variables such as tumour size, histological grade, and hormone receptors were not significantly different in the groups having received IMN RT or not. Considering all patients, OS was strictly comparable in the 2 groups: 10-year values were 85% (IMN RT) and 86% (no IMN RT), respective values at 20 years were 66.6% and 61.0% (p=0.95). However, in patients presenting with inner/central tumours, OS was significantly improved in the IMN RT group with respective values of 92.5% and 87.2% at 10 years, and 80.2% and 63.3% at 20 years: Hazard ratio (HR)=0.56 (0.37-0.85); p=0.0052. Again, CSS was improved in patients with inner/central tumours having received IMN RT, with 20-year rates of 89.5% versus 79.1% in patients not receiving IMN RT (p=0.047). No difference in DFS was noticed. The actuarial rate of CBC development was comparable between patients having received IMN RT and other patients. However, considering only patients alive 10 years after primary breast surgery, the K-M rate of CBC at 20 years was 5.3% in patients without IMN RT and 7.2% in patients with such RT; HR=2.47 (1.23-4.95); p=0.008.
IMN RT in node-negative tumours was associated with increase in OS and CSS in patients with inner or centrally located lesions. An increase in CBC development was also noticed in long-survivors of IMN RT patients; however, these findings have to be interpreted with caution because of the difference in follow-up between the 2 groups. Further studies are warranted to investigate the potential role of IMN irradiation in the development of CBC.
关于腋窝淋巴结阴性乳腺癌患者内乳淋巴结（IMN）的放疗（RT），目前尚无普遍共识。基于在单一机构治疗并长期随访的大量患者，我们研究了IMN放疗对这些患者远期预后以及对侧乳腺癌（CBC）发生情况的影响。
本研究基于1975年至2008年间在我院接受治疗的1630例淋巴结阴性乳腺癌患者，这些患者均接受了保乳手术及腋窝清扫或前哨淋巴结检查。所有患者均接受术后乳房放疗。IMN放疗在位于内侧或中央的肿瘤患者中更为常见。计算了所有患者以及内侧/中央肿瘤患者根据IMN放疗情况的Kaplan-Meier（K-M）总生存（OS）、癌症特异性生存（CSS）和无病生存（DFS）情况。还分析了对侧乳腺癌（CBC）的K-M发生率，并将其与IMN放疗情况进行关联。
接受或未接受IMN放疗的两组患者在肿瘤大小、组织学分级和激素受体等预后变量方面无显著差异。考虑所有患者，两组的OS严格可比：10年生存率分别为85%（IMN放疗组）和86%（未进行IMN放疗组），20年生存率分别为66.6%和61.0%（p = 0.95）。然而，对于内侧/中央肿瘤患者，IMN放疗组的OS有显著改善，10年生存率分别为92.5%和87.2%，20年生存率分别为80.2%和63.3%：风险比（HR）= 0.56（0.37 - 0.85）；p = 0.0052。同样，接受IMN放疗的内侧/中央肿瘤患者的CSS有所改善，20年生存率为89.5%，而未接受IMN放疗的患者为79.1%（p = 0.047）。DFS未发现差异。接受IMN放疗的患者与其他患者之间CBC发生的精算率相当。然而，仅考虑初次乳腺癌手术后存活10年的患者，未接受IMN放疗的患者20年CBC的K-M发生率为5.3%，接受IMN放疗的患者为7.2%；HR = 2.47（1.23 - 4.95）；p = 0.008。
淋巴结阴性肿瘤患者的IMN放疗与内侧或中央病变患者的OS和CSS增加相关。在IMN放疗患者的长期存活者中也注意到CBC发生率增加；然而，由于两组随访情况不同，这些结果必须谨慎解读。有必要进一步研究IMN放疗在CBC发生中的潜在作用。
