Health services research in patients with breast cancer (CAMISS-prospective): study protocol for an observational prospective study oleh Susana García-Gutierrez, Miren Orive, Cristina Sarasqueta, Maria Jose Legarreta, Nerea Gonzalez, Maximino Redondo, Amado Rivero, Pedro Serrano-Aguilar, Xavier Castells, Jose Maria Quintana, Maria Sala, on behalf of REDISSEC-CaMISS group