- QTc prolongation (defined as a QTc interval ) > 480 msecs using Bazett's formula) or other significant ECG abnormalities d. Symptomatic, untreated, or uncontrolled CNS metastases or seizure disorder. Patients with CNS metastases treated with whole brain radiation (WBRT)or gamma knife may be enrolled after completion of WBRT or gamma knife. Patients may begin chemotherapy as early as the next day after completion of WBRT or gamma knife.