If an asymptomatic patient requires a delay up to a week before starting chemotherapy for Stage III lung cancer, do you also push back the radiation start date?

Typically, the reason for B12 and folate prior to chemotherapy is related to the drug that will be used, pemetrexed. Giving the premedication reduces hematologic and gastrointestinal toxicity to tolerable levels.

One week typically will not make a difference and I would usually wait to start. However, there is no clear data or rule that states chemo and radiation should start concurrently on day 1 unless on a clinical trial. Therefore, I think it is still OK to start the radiation first if there...

I would first ask the medical oncologist why they are planning on giving Vitamin B and folate and why that has to delay chemotherapy initiation by a full week. If there is a good reason for this, if the patient is asymptomatic, and if the kinetics of disease growth is relatively slow, then a 1-week delay in starting radiation would not likely make a large difference and I would probably wait to start RT concurrently with the chemo. However, if there is significant clinical urgency to starting tr...

I agree with my colleagues. My presumption in this case is that this is a definitive treatment for stage III. Stage III patients requiring urgent symptomatic relief by RT are not patients I would have been entertaining concurrent therapy to begin with. Since one of the (presumed) benefits of the addition of chemotherapy to radiotherapy is sensitization, I would not start the RT and would wait for a concurrent start. Typically trials allow for RT to start within 24hrs after the CHT but not before...

While I do not see tremendous harm in delaying therapy for a week, I do not really feel the delay is necessary and would avoid it.

B12 and folate are given to minimize toxicity of pemetrexed. While I do not typically use this regimen for stage III NSCLC, it is certainly a reasonable one. Vitamin supplementation is important. In the randomized phase III trial of cis/pem vs cis in mesothelioma, B12/folate supplementation was mandated midway through the study and you can see a clear impact on both h...