how do cancer cells spread to cause leptomeningial disease ? - 1271896

Hi Kempten,

The assumption is that cancer cells reach the CNS through the bloodstream, and recent research supports that hypothesis, although it is also possible for those cells to enter the lymph system.

I'm not aware of any evidence that the presence, lack or extent of brain metastases predicts later development of LC. For example my late wife, as well as a number of other GRACE members, had no brain mets at the time of diagnosis but later developed LC. The frequency of LC diagnoses has increased as some stage IV patients achieve longer survival; my wife's LC appeared about three years after diagnosis.

As far as your hypothetical question, I would say that if you have "somewhat controlled" brain mets and presumably substantial microscopic brain disease, and have never had whole brain radiation, there is good reason to start with that proven therapy rather than relying on the uncertain possibility that a third generation EGFR inhibitor will penetrate the blood brain barrier in sufficient concentrations to successfully treat the disease in the brain or prevent it from causing LC. If you are concerned about LC, choosing the systemic therapy may give the cancer cells in the brain more time to spread to the cerebrospinal fluid.

In addition, since you'd like to get the maximum benefit from each line of treatment, you might not want to begin third generation EGFR therapy until you are certain you need it.

JimC
Forum moderator

As Jim tried to explain, just because you had/have brain mets doesn't mean you're at higher risk for lepto. Many people with brain mets never get lepto and some without do, so there's no way to know who will or won't. Because people are living longer with cancer, lepto becomes a possibility. Your fear is taking over. Talk with your doctors about your concerns and ask these questions if you haven't already. They're the only ones that can agree or not to change your treatment. Take care, Judy
P.S. I am not a medical professional or forum moderator, just a lung cancer survivor.

Kempten,

From personal experience, I understand your concern about LC. I don't think you can assume lepto is a foregone conclusion, just as you can't assume that Tagrisso will be as effective in the CNS as Tarceva seems to have been. Even if it is, there's no way to know if that will delay or prevent lepto.

Although it does happen at times, most patients do not experience significant cognitive side effects from WBR, even when they have had previous treatment with SRT.

JimC
Forum moderator

Kempten, the "what if's" will drive you crazy. You made a decision back then based on the info you had at the time. Second guessing it now, won't change anything. Move forward and continue the fight! If you decide to do WBR, ask for Namenda. It helps been shown to help reduce cognitive changes. You will have short term side effects but not necessarily long term side effects from WBR.
Take care, Judy