Monitoring disease response in chronic-phase chronic myeloid leukemia: the age of molecular assays?

An 80-year-old man has newly diagnosed chronic myeloid leukemia. His BM and blood examination at diagnosis confirms chronic-phase disease, with the Philadelphia chromosome as the sole cytogenetic abnormality. He has intermediate Sokal and Hasford risk,(1) and is started on imatinib 600 mg once daily. He lives 5 hours away from the nearest specialist hematology service and prefers followup with his local physician, who cannot perform BM examinations. In patients such as this, is it acceptable to monitor his therapeutic response solely with molecular studies of his peripheral blood?