A Prospective Study to Evaluate FDG-PET, Breast MRI, and Breast Ultrasonography in Monitoring Tumour Responses in Patients With Locally Advanced Breast Cancer (LABC) Undergoing Neoadjuvant Chemotherapy (PETLAB)

Locally advanced breast cancer (LABC) is usually treated with neoadjuvant chemotherapy followed by surgery and radiation. At present, monitoring of tumour responses to chemotherapy is primarily carried out using physical examination at the beginning of each chemotherapy cycle. Differentiating viable tumour tissue from inflammation or fibrotic scar tissue can be difficult. There is a growing body of evidence that newer imaging techniques such as positron emission tomography (PET) and magnetic resonance imaging (MRI) may be better at determining whether or not the tumour is actually shrinking. The purpose of this study is to determine the sensitivity and specificity of PET, MRI and ultrasound in evaluating tumour responses to chemotherapy in patients with LABC and compare this with physical examination, which is the current standard of care.

Two of the objectives of this study are to 1) determine whether PET, MRI or ultrasound have a higher sensitivity/specificity than physical examination alone in determining which LABC patients achieve a complete pathologic response following neoadjuvant chemotherapy, and 2) to investigate whether these additional investigations might lead to changes in clinical management by identifying non-responders earlier than with physical examination alone.

A prospective cohort study design will be conducted. Patients with LABC who receive chemotherapy will undergo physical examination, PET, MRI, and ultrasound at baseline, midway, and at the completion of chemotherapy. Approximately 100 patients will be accrued over a 5-year period.

This study will give clinicians further insight into the usefulness of PET, MRI, and ultrasound in monitoring treatment responses in patients with LABC. This could potentially lead to changes in clinical management of these patients.