Should decisions on internal mammary lymph node irradiation be based on current lymphoscintigraphy techniques for sentinel lymph node identification?
BACKGROUND
Treatment of internal mammary lymph node (IMN) metastases remains controversial because of the difficulty in predicting involvement, potential treatment-related morbidity, and questionable efficacy. Lymphoscintigraphy with sentinel lymph node biopsy offers a means to identify occult involvement of IMN, allowing appropriate patient selection for IMN treatment.


METHODS
The authors retrospectively reviewed 262 lymphoscintigraphies (LS) of 248 patients treated at the University of Florida (Gainesville, FL) between 1998 and 2002. Tumor characteristics were assessed for their value in predicting IMN drainage and their association with IMN radiation.


RESULTS
Lymph flow to the IMN was documented with LS in 23 of 262 tumor specimens (9%). Flow to the IMN was not correlated with any of the five factors: tumor location, tumor size, lymphovascular invasion, pathologic lymph node status, and laterality of the involved breast (right vs. left breast). Identification of IMN flow increased from 5.7% to 10.1% with the use of a deep injection technique. IMN radiotherapy was used more frequently in patients with larger tumors (15 of 188 in Tis/T1 vs. 31 of 70 in T2-T4; P<0.0001) and positive lymph nodes (17 of 91 in lymph node-negative patients vs. 28 of 66 in lymph node-positive patients; P<0.0001). In patients with T2N0 tumors (n=32), IMN radiotherapy was used more frequently with medial tumors (5 of 11 [45%]) than with lateral tumors (4 of 21 [19%]).


CONCLUSIONS
The incidence of flow to the IMN documented with the current LS technique was low compared with other LS and extended radical mastectomy series. Histopathologic information was obtained for the sentinel IMN when IMN flow was identified on the LS. In the absence of histopathologic information, treatment decisions should continue to be based on clinical factors known to be correlated with occult IMN involvement.
Benda
Rashmi K
RK
Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, Florida 32610-0385, USA. bendark@shands.ufl.edu
Cendan
Juan C
JC
Copeland
Edward M
EM
Feezor
Robert J
RJ
Lind
D Scott
DS
Morris
Christopher G
CG
Mendenhall
Nancy Price
NP
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy*; D015331:Cohort Studies; D004322:Drainage / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology*; D015182:Lymphatic Irradiation / Q000592:standards* / Q000639:trends; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009367:Neoplasm Staging; D011336:Probability; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy; D016019:Survival Analysis; D016896:Treatment Outcome