Recent advances: diagnosis and treatment of early breast cancer

Introduction

When this review was commissioned, the topic seemed straightforward: early breast cancer. But I struggled, writing pages of unfocused and confusing material, darting back and forth between invasive and non-invasive disease. The problem stemmed from the fact that there is no universally accepted definition of what constitutes early breast cancer. Should an early lesion be defined by size, by the amount of invasion, by lymph node negativity, by clinical or histologic findings, by how long it has been growing? What was meant by early breast cancer 30 years ago, what is meant by early cancer today, and what will be meant by early cancer five to 10 years from now are all different. In addition, today's biologists, geneticists, and clinicians all define early breast cancer differently.

Defining early breast cancer

In 1971 Gallagher and Martin coined the term “minimal breast cancer.”1 It included ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS) of any size as well as invasive breast carcinoma with a diameter of 5 mm or less. The object was to create a group of lesions with a nodal positivity rate of 5% or less and a survival probability of 90% or more at 10 years. Today, no one should consider grouping these three disparate lesions together. Lobular carcinoma in situ is a risk factor for the later development of invasive breast cancer; the risk is shared equally by both breasts, and most clinicians do not recommend any treatment.2 3 Ductal carcinoma in situ is a heterogeneous group of lesions so diverse and complicated, that a 70 chapter textbook has just been published entirely about it,4 and it should not be grouped with small invasive breast carcinomas.

Thirty years ago, early breast cancer was a palpable lesion, almost always invasive, with a diameter of 2 cm or …