Hi Bev,
The radiation side effects might not even PEAK until 8-10 weeks after the last treatment. Sure was true with my son the zombie. He's pretty peppy now.
Best wishes!
Sarah
www.abta.org:
Early Delayed (Sub Acute) Reactions
This group of reactions occurs a few weeks to a few months after completion of therapy, most commonly between one and three months. Symptoms include loss of appetite, sleepiness, lack of energy, as well as an increase in pre-existing neurologic symptoms.
Some of these reactions are thought to be due to a temporary disruption of myelin formation (demyelination). Myelin is a substance that insulates the nerves and speeds up nerve impulses. The symptoms are usually temporary lasting about six weeks, the length of time it takes for myelin to repair itself. In some cases, however, recovery may take several months.
Since the brain lacks an effective lymph system, dead tumor cells are cleared away very slowly. A rapid build-up of dead cells can lead to swelling which might produce a temporary increase of symptoms. CT scans taken shortly after treatment might show changes that are difficult to distinguish from tumor growth. Repeat CT or MRI scans are often necessary to clarify the cause of the symptoms.
Management of early delayed reactions
Notify your radiation oncologist or your primary doctor if you notice any of the symptoms listed. Early delayed reactions are usually treated with steroids and most of these reactions are self-limiting, going away with minimal treatment. However, they can become life-threatening if they aren't treated properly. It is very important for you to tell your doctor if you have any of these reactions so that he/she can properly monitor and treat you.
Leukoencephalopathy is a type of early delayed reaction affecting the white matter (mylenated tissue) of the brain. It can occur when dead tumor cells, radiation therapy, or chemotherapy drugs irritate the white matter. The severity of the symptoms increases with the amount of damage. Leukoencephalopathy may be reversible and is usually treated with steroids. Some researchers are attempting to treat this effect with hyperoxygenation therapy in the hope that increasing the amounts of oxygen in the brain will aid in healing brain cells which may not be as seriously damaged as others.
Late Reactions
These reactions are due to changes in the white matter and death of brain tissue caused by radiation-damaged blood vessels. Symptoms can occur months to years after therapy is completed. These long-term effects are permanent and can be progressive. Symptoms vary from mild to severe and include: decreased intellect, memory impairment, confusion, personality changes, and alteration of the normal function of the area irradiated.
It is sometimes difficult to diagnose late delayed reactions. CT and MRI scans are often unable to distinguish between new tumor growth and radiation changes. PET scanning might be helpful, but is not totally accurate. A biopsy of the area may be the only way to determine whether you have radiation changes to your brain or new tumor growth.
Management of late delayed reactions
Mild reactions may be treated with steroids. Severe reactions such as tumor necrosis may require surgery to remove the dead tissue. Some researchers are investigating the possible benefits of hyperoxgenation therapy in the hope that increasing the amounts of oxygen in the brain will aid in healing brain cells which may not be a seriously damaged as others. Still other researchers have attempted to treat the brain with blood thinners, such as heparin, but this has not proven successful.