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how soon can you tell if the chemotherapy is working?

Posts: 74
Joined: Sep 2012

Just wondering how soon can you tell if the chemotherapy is working?
My daughter will be starting soon. I am wondering if they check often and
how they check, thanks

Posts: 1170
Joined: Sep 2012

If there is a tumor that can be seen from a scan it is easy to monitor. They usually do a scan every eight weeks (after four chemo sessions). If the chemo is working the tumor should be smaller after four chemo sessions. If no cancer can be seen from a scan it is more difficult to know if the chemo is working because you don't know if anything is shrinking. This is how they seem to do things at my husbands cancer clinic. When there is no area of visible cancer to monitor, I think they just give twelve sessions of chemo and hope for the best (and then monitor every two or three months).


Posts: 1961
Joined: Aug 2003

My experience is similar. I have a scan (usually PET, sometimes MRI) after every 4 chemo cycles. I also have a blood test before each chemo cycle - which includes CEA (the blood marker for colorectal cancer). CEA is not reliable for some people -- for others, it can be a pretty good indicator of what is going on. But scans are the 'gold standard' as CEA can do strange things (go up as tumours are disappearing, etc).

As Chelsea says, this is for when you have a tumour or tumours. When I have had 'mop up' chemo (ie after surgery, to try to attack any invisible 'micrometasteses'), I have had scans less frequently -- perhaps after all planned cycles (eg 8) or maybe even after 6 mos (sorry can't remember - chemobrain!)


steveandnat's picture
Posts: 887
Joined: Sep 2011

Usually after 3 months I would get ct scans to see what is going on with the tumor. Pray everything goes smoothly with your daughter. Jeff

JayhawkDan's picture
Posts: 206
Joined: Apr 2012

CEA tests and scans gave my doctors a good indication that things were going in the right direction. CEA started at 44, then 43, then 12, and several more drops to right around 1 after 9 months of tx. But my best indicator was they told me I would start feeling better right away after starting chemo. The colonoscopy that started this whole thing showed 90% blockage of the rectum, which was causing considerable pain and discomfort, and prompted me to find out what was wrong. Within 2 weeks of chemo, I could tell the primary tumor in the rectum was shrinking because I felt much, much better. So for me, it was how I actually felt, along with the tests. Good luck and Godspeed. Dan

Annabelle41415's picture
Posts: 4560
Joined: Feb 2009

My doctor didn't schedule any follow up scans until after done with treatment and no follow up colonscopy until 18 months after diagnosis so it depends on the doctor.


herdizziness's picture
Posts: 3649
Joined: Apr 2010

It is my CEA count, after my first chemo last month, my CEA count went down 5 points so I have confidence the chemo is working, but CEA has been a good indicator for me, my onc gets my blood done along with CEA each chemo. After a few rounds then a CT scan is done. This time also I noticed a pain had disappeared in my left side of chest, I thought it was my heart stent that had been the source of pain, but a few days after chemo the constant pain I've had for 3 months went away, so I'm thinking it must have been that pesky lung tumor (apparently now shrinking) that had been the source of pain after all, I've really got to start paying attention to these annoying pains in my body, obviously they've been trying to tell me something.
Winter Marie

Posts: 372
Joined: Aug 2006

They are all right the CEA and scans if they read them right can indicate if the chemo is working on what they can detect. My advise don't get caught up in the numbers and scans. Generally they work and suggest to the ONC what is working for your situation and in that their value may exist. Best of luck Lou

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