How would you manage a patient with glioblastoma planned for concurrent radiation and chemotherapy but unable to start temozolomide due to underlying comorbities?   

In a patient with glioblastoma who is planned for concurrent radiation and temozolomide (per EORTC/NCIC), but unable to start temozolomide in a timely manner due to comorbidities (e.g. chronic hepatitis, tuberculosis infection), how would you proceed and why? Delay radiation? Begin radiation and add temozolomide once able? Would gross-total versus subtotal resection play a role in this decision?