Question regarding carboplatin and alimta - 1289874

kcarn0927
Posts:48

My husband: Stage IV NSCLC with micro brain mets, liver met, spine mets (treated with photon radiation in 2013), EGFR, Exon 21, L858R. Tagrisso was started in December of 2015. Lost T790M in June 2016. Carboplatin/Alimta was added in September of 2016.

Chemo combo was started due to pain he was having and the Tagrisso was not reaching those areas (i.e. pleural effusion was causing rib pain, sneezing was a problem and spasm in abdominal area). All have since went away once he started systemic chemo. He finished up Cycle 4 and will start maintenance Alimta. By the way, he is stable at this point both neck down and brain. He has tolerated this combo very well with very little issues.

Also as a side note, he was treated with SBRT radiation in September 2016 on one liver met and the primary lung mass was treated with SBRT radiation in July 2016). Everything has shrunk and/or disappeared and no pain.

On this chemo combo he has had to delay it every 4 weeks due to low platelets (below 100). The oncologist did mention being off carboplatin may improve platelets.

My question: is there any data regarding stopping carboplatin at Cycle 4 or going the whole distance to Cycle 6 as far as effectiveness??? I did not know that there was a Cycle 5 and 6 at the time of the visit (learned it later after the visit). My only comment to the oncologist was that I was concerned if the carboplatin was stopped would progression be sooner. He said it was protocol to stop at Cycle 4 and to go to maintenance as there is a risk of allergic reactions by staying on carboplatin. Thanks!

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JimC
Posts: 2753

Hi cc1990,

It's good to hear that your husband has responded so well to Carbo/Alimta. The majority of oncologists do tend to cease treatment with this regimen after 4 cycles. There are two major reasons for this. First, the greatest response (tumor shrinkage) tends to occur with the first two cycles, with continued response in cycles three and four, but additional cycles beyond that point do not tend to produce much added response. Second, platinum agents such as carboplatin tend to cause cumulative side effects, in particular a reduction in bone marrow function, which can make future chemotherapy problematic. There are instances, though, when adding the two additional cycles may be beneficial.

Dr. Weiss has addressed this previously: "There is controversy regarding the optimal number of cycles in 1st line. A trial was done comparing four cycles of carboplatin-based therapy to indefinite carboplatin-based therapy; survival was similar, but toxicity was worse with indefinite therapy. A comparison of four cycles to five or six has never been done.

I base my daily decision on 4 vs 6 cycles based on response and on patient tolerance after 4 cycles. If a patient is tolerating therapy beautifully and the tumor has continued to shrink, I'm more inclined to give the 5th and 6th cycles. If the patient has issues with tolerance and the tumor is no longer shrinking, then I think to stop carboplatin and consider either maintenance or active surveillance." - http://cancergrace.org/forums/index.php?topic=4142.msg24444#msg24444

And there have been other discussions regarding the length of treatment:
http://cancergrace.org/lung/2007/12/16/duration-of-first-line-chemo-in-…
http://cancergrace.org/forums/index.php?topic=464.0

Finally, Dr. West has discussed the concept of continuing the non-platinum agent as maintenance therapy here: http://cancergrace.org/lung/2011/12/24/beyond-4-cycles-1st-line/

JimC
Forum moderator

kcarn0927
Posts: 48

JimC, thank you very much for your response... I have another question. My husband was due for Cycle 5 to start Alimta maintenance on Thursday, 1/26 (week 4), but due to low platelets was canceled. Instead of platelets rebounding, they decreased even more. Platelets went from 69 to 29. He has always rebounded just making it to over 100. Tagrisso was also stopped until Thursday. Right now he is waiting it out until next Thursday, 2/2 to try again; hopefully, platelets will have increased... but, if platelets were really 29, with his history so far, I don't think they will make it to over 100 unless this was lab error. Otherwise, he feels very well, no symptoms.

Could this be lab error?

Thanks!

JimC
Posts: 2753

Hi cc1990,

I suppose it's possible, but it would be more likely that the cumulative effects of chemotherapy have caused such a drop in platelets. Delaying chemo in such circumstances is not at all uncommon, and I hope your husband's counts rebound soon (also not uncommon).

JimC
Forum moderator