Sue
forgive me only going on your profile but sometimes going back through posts and threads can be really difficult. I had no idea you are no stranger to SCCs poor you.
Calcium and Potassium (and a few other iums) should be tested for every time chemo or blood transfusions are done so yes they should have been picked up if there was an issue. However they can rise or fall pretty quickly so being aware of the symptoms of too much or too little of them can be handy. As your OH is in current chemo treatment the frequency these are checked should be sufficient.
The fact that your Husband has already had an SCC may be a contributory factor to his leg pains if his lumbar spine area was treated post SCC then this sometimes can cause the legs to spasm, cramp and hurt. Maybe the chemo is just bringing that on. Although my Husband Mick was not able to stand or walk after his first SCC he could still wiggle his toes and had some feeling in his legs. The nurses at the hospice swore he played football at night in bed because, despite being in a great central position at bedtime, in the morning his legs would often be as far as way from centre as possible. Having observed him for a while I noticed that he had what looked like resless leg syndrome. He had no idea he was moving his legs, it was a form of muscle/nerve spasms.
I would definitely mention it next time you see the medical team as if he is not already having nerve pain/spasm medication like Lyrica they may try that for a while to see if it helps. I also found that putting a pillow under Mick's knees when he was laying down also helped a little.
So many different things that can happen and no man seems to have an identical journey with this horrid disease. I think sometimes it even confounds the specialists!!
All my best wishes
xx
Mo