Monitoring Response After The First Chemotherapy Cycle In Newly Diagnosed Breast Cancer As A Guide For Neoadjuvant Therapy

The use of neo-adjuvant systemic therapy in women recently diagnosed with breast cancer is growing in popularity based on its proven benefit (1). Pre-operative chemotherapy not only can assist in regards to breast conservation therapy (2) but data suggest prognostic benefits in those subset of patient's obtaining complete pathological response (3,4) .

It is imperative for clinicians to detect as early as possible those patients likely to obtain the desired clinical and /or pathologic response, thus identifying those patients who don't benefit from the first line neoadjuvant treatment so that their treatment can be modified accordingly.

Response to treatment based on clinical data or structural imaging, usually requires several chemotherapeutic cycles to establish degree of effectiveness (5). Lately, FDG-PET/CT has been used in different types of neoplasms, breast cancer among them, to establish early response to treatment (6,7). Recent data has established the usefulness of metabolic analysis via FDG-PET, in separating subgroups of chemotherapy. For such analytical approach, sequential estimation of SUVs (Standardized Uptake Value) have been measured along the duration of the treatment. Reduction in SUVs presumes adequate response to treatment (8), while little or no change in metabolic activity presumes sub-optimal response .

However, no definite consensus has been established in regards to what degree of metabolic response is predictive of the desired clinical benefit, particularly early in the treatment . Establishing such criteria could potentially serve as a guideline for monitoring neoadjuvant treatment. Schelling et al, was able to separate a group of patients that eventually showed either progression of the disease or no clinical response as early as the first course of chemotherapy.

The aim of our study is to establish a simple formula using FDG-PET/CT, as early as the first course of chemotherapy, to stratify patients undergoing neoadjuvant chemotherapy for recently diagnosed breast cancer. Those who will benefit from continuing the same treatment will be regarded as responders versus non-responders, which are those in need of changing strategy.