High intersystem variability for the prediction of additional axillary non-sentinel lymph node involvement in individual patients with sentinel node-positive breast cancer.
OBJECTIVE
To compare the outcomes of the available systems that predict the risk of non-sentinel lymph node (non-SLN) metastasis and to evaluate the variability within a group of SLN-positive breast cancer patients.


METHODS
Predicted probabilities and scores for non-SLN metastasis were calculated with nine predictive systems for 120 SLN-positive patients who underwent a completion axillary lymph node dissection. The number of patients was calculated that were considered low risk or had a probability of ≤ 10% by at least one of the systems. For each nomogram, a box plot was constructed. All patients with a predicted probability of ≤ 10% according to the Memorial Sloan-Kettering Cancer Center (MSKCC) nomogram were selected, and a comparison was made with the probabilities predicted by the other systems.


RESULTS
Nearly two-thirds (64.2%, n = 77) of patients with SLN-positive breast cancer were allocated to a low-risk or low-probability group by at least one of the predictive systems. No patients were uniformly classified as low risk by all nine prediction models. At the group level, a considerable variation in the distribution of the predicted probabilities was observed. At the individual level, calculation of the predicted probabilities for the selected patients who were considered low risk (≤ 10%) according to the MSKCC nomogram, showed even larger variations, ranging from 4 to 94%.


CONCLUSIONS
This study shows that there is an unacceptably high variability in individual predictions when the predictive systems that are currently available are used to predict non-SLN metastasis in patients with SLN-positive breast cancer.
Department of General Surgery, Máxima Medical Centre, Veldhoven, The Netherlands. i.vandenhoven@mmc.nl
Ingrid
I
van den Hoven
Gerrit P
GP
Kuijt
Adri C
AC
Voogd
Rudi M H
RM
Roumen
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis* / Q000601:surgery; D018275:Carcinoma, Lobular / Q000175:diagnosis* / Q000601:surgery; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000601:surgery; D009367:Neoplasm Staging; D049451:Nomograms; D011379:Prognosis; D021701:Sentinel Lymph Node Biopsy