Introduction: Breast cancer is a disease with a very variable progression. Primary tumour size and metastatic lymph node involvement are the best indicators of the likelihood of relapse. However, their value in predicting progression following relapse is not clear.
Aim: The aim of this study was to asses whether the relationship between tumour size and the number of lymph nodes involved had any value as predictive factors of post-relapse progression.
Method: We established an index defined as the quotient between the number of diseased lymph nodes and the tumour size (in cm).
Results: Applying this index in 230 consecutive patients with metastatic breast cancer, we observed that there was a significant inverse relation between the index and post-relapse progression.
Conclusion: We conclude that, at the time of initial diagnosis, the quotient of tumour size and the number of diseased lymph nodes could be a good predictor of time-to-progression following the diagnosis of the metastatic disease.