Is elective nodal irradiation beneficial in patients with pathologically negative lymph nodes after neoadjuvant chemotherapy and breast-conserving surgery for clinical stage II-III breast cancer? A multicentre retrospective study (KROG 12-05).
BACKGROUND
To evaluate the effects of elective nodal irradiation (ENI) in clinical stage II-III breast cancer patients with pathologically negative lymph nodes (LNs) (ypN0) after neoadjuvant chemotherapy (NAC) followed by breast-conserving surgery (BCS) and radiotherapy (RT).


METHODS
We retrospectively analysed 260 patients with ypN0 who received NAC followed by BCS and RT. Elective nodal irradiation was delivered to 136 (52.3%) patients. The effects of ENI on survival outcomes were evaluated.


RESULTS
After a median follow-up period of 66.2 months (range, 15.6-127.4 months), 26 patients (10.0%) developed disease recurrence. The 5-year locoregional recurrence-free survival and disease-free survival (DFS) for all patients were 95.5% and 90.5%, respectively. Pathologic T classification (0-is vs 1 vs 2-4) and the number of LNs sampled (<13 vs ≥13) were associated with DFS (P=0.0086 and 0.0012, respectively). There was no significant difference in survival outcomes according to ENI. Elective nodal irradiation also did not affect survival outcomes in any of the subgroups according to pathologic T classification or the number of LNs sampled.


CONCLUSIONS
ENI may be omitted in patients with ypN0 breast cancer after NAC and BCS. But until the results of the randomised trials are available, patients should be put on these trials.
Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul 135-710, Republic of Korea.
J M
JM
Noh
Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul 135-710, Republic of Korea.
W
W
Park
Department of Radiation Oncology, Yonsei Cancer Center, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Republic of Korea.
C-O
CO
Suh
Department of Radiation Oncology, Yonsei Cancer Center, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Republic of Korea.
K C
KC
Keum
Department of Radiation Oncology, Yonsei Cancer Center, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Republic of Korea.
Y B
YB
Kim
Proton Therapy Center, Research Institute and Hospital, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769, Republic of Korea.
K H
KH
Shin
Department of Radiation Oncology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul 110-799, Republic of Korea.
K
K
Kim
Department of Radiation Oncology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul 110-799, Republic of Korea.
E K
EK
Chie
Department of Radiation Oncology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul 110-799, Republic of Korea.
S W
SW
Ha
Department of Radiation Oncology, Asan Medical Center, University of Ulsan, College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea.
S S
SS
Kim
Department of Radiation Oncology, Asan Medical Center, University of Ulsan, College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea.
S D
SD
Ahn
Department of Radiation Oncology, Bundang CHA Hospital, School of Medicine, CHA University, 59 Yatap-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 463-712, Republic of Korea.
H S
HS
Shin
Department of Radiation Oncology, Dongsan Medical Center, Keimyung University School of Medicine, 56 Dalseong-ro, Jung-gu, Daegu 700-712, Republic of Korea.
J H
JH
Kim
Department of Radiation Oncology, Dong-A University Hospital, Dong-A University School of Medicine, 26 Daesingongwon-ro, Seo-gu, Busan 602-715, Republic of Korea.
H-S
HS
Lee
Department of Radiation Oncology, Korea Medical Center, Korea University School of Medicine, 73 Inchon-ro, Seongbuk-gu, Seoul 136-705, Republic of Korea.
N K
NK
Lee
Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul 135-710, Republic of Korea.
S J
SJ
Huh
Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul 135-710, Republic of Korea.
D H
DH
Choi
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000473:pathology / Q000628:therapy*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D015182:Lymphatic Irradiation / Q000379:methods*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D012189:Retrospective Studies; D055815:Young Adult