Hypermutation Risks of Temodar

Hi all,
I've found great value in this blog and am posting for the first time.

I was diagnosed in march 2016 with grade 2 oligo.  Its a somewhat larger tumor, about 7x6x5cm and unlike most oligo's is not in the frontal lobe, but is left parietal and overlapping motor, sensory and speech areas and nearing midline crossover.  Because of all that it was considered a high risk surgery zone and so I have so far only had a biopsy and have been doing chemo.   I'm IDH1 mt, mgmt meth, 1p19q codel, ATRX normal, p53 normal.

So the broad plan was chemo then RT.  The hope was to shrink the tumor to be able to reduce the RT zone. So far 6 rounds of Temodar but I have now switched over and done 1 round of CCNU after having learned more about hypermutation risks with TMZ.

I've dug thru what published data there is and its all clear as mud.  On the one hand the 2014 Science paper (Johnson et al from the Costello UCSF lab) that seems to have really launched this topic found very clear and scary linkages showing hypermutation and upgrading at recurrance to GBM in about half of the patients treated with TMZ vs none with only RT, on the other hand it was a very small data set, had mixed genetics, was clearly a selected dataset and not randomized, and only looked at TMZ alone or RT alone, not the more common RT+TMZ.  The few other studies I have found add some implications that mutations in TP53 and mismatch repair genes  increase the risk, though some data also shows TMZ driving mutations of TP53 and MSHx which then creates the path to hypermutation.

In simplified terms if chemo mutates the cancer to a point where the 'self check' mechanisms during cell division stop working then the next time the cell gets hit with chemo it will go ahead and replicate in spite of the genetic damage from chemo and create new set of mutations.

To further complicate the picture most of the historical data looking at different chemo options is comparing PCV to TMZ, but procarbazine is a monoalkylating agent that is quite similar to TMZ.  So I've gotten some input from Doc's that CCNU alone may be less mutagenic because it is a bi-alkylating agent and will more effectively stop DNA replication thru double strand breaks.

So Steven or others who are into the science side of cancer, do you have any thoughts on how to unravel all this?  Recommendations on other approaches to consider, or ways to enhance effectiveness of chemo for low grade cases?

Thanks,
Bryan

SW edited this post to include the image below, from a presentation at the 2016 SNO conference in Phoenix Arizona:

Help in moving forward with 20 year old son diagnosed with Grade 2 Astroscytoma

Thank you Stephen for the invite, and thank you to this community for all information gathered here, and Astrocytoma Options, regarding my sons recent diagnosis of a Grade 2 Astrocytoma.

This is all very overwhelming, in processing a lot of information, in a short period of time, while making decisions regarding treatments and such.

My son Brett, had a bad seizure on Christmas eve morning while playing football with his friends. Fast forward, he had surgery the following Friday, December 30th. His tumor was located on his right frontal lobe(cerebral), apparently just over 4 centimeters.

Post-op MRI report stated a full resection, however the Neurologist who preformed surgery said that he feels as though a piece, possible the rim of the tumor remained. When discussed with the tumor board, the over all consensus of the group, agree with him. Being that is it a slower grower tumor, that are allowing his body to heal, and have scheduled his next MRI next week, to further review.

We met with his Neuro Oncologist yesterday to go over his pathology report. Which is where I am seeking advice. Trying to stay positive through all of this, I felt like a UFC fighter kicked my in my stomach when I learned that his tumor is IDH1 negative, 1p/19q not co-deleted(none detected), his TP53 mutation: Present, 60 percent of nuclei stain positively by immunohistochemistry.

We have an appointment at UPenn Thursday afternoon for a second opinion. Do you have any recommended questions, regarding anything? I am starting to feel lost. From what I have read(very carefully), prognosis is quite favorable with IDH1 mutated, co-deletion in tact.

She offered us a treatment of radiation w/ Tremodar, or radiation 5x's a week followed by a restrictive diet chemotherapy, Matulane, Lomustine, Oncovin. She does not lean one way or the other. The choice is ours, however, she stated that statistics back up the second suggestion. I read that combination chemo and radio are best.

Please forgive me for throwing this all out there, I'm writing in my car while picking up my 12 and 14 year old from school. Absolutely and advice would be much appreciated!!

Sincerely,

Marlena

Off label drugs for astrocytoma grade 3

We are looking for repurposed drugs for a family member and since most of the research has been done for GBM that is grade 4 tumor I wonder if there is anything to take into account while treating a grade 3 tumor. I once read somewhere, but can't remember where and how reliable this source was, to be careful with cytotoxic drugs for lower stage cancer as they may cause the tumor to develop to a higher grade. Could you let me know what are your opinions on this? What type of drugs would you chose or have you chosen for lower grade tumors? Thank you.