During my treatments with Cisplatin and Gemcitabine, I had some swelling in the calf of my left leg. The oncologist examined it and said we'd watch it. 3 months after completion of the chemo, my leg swoll up much more, and cramping and pain were pretty intense. Diagnosed at the ER as blood clots. I got on blood thinners and it is under control.
I have been told by the oncologist and radiologists that such clots are fairly common in chemo patients. If you notice swelling or pain, my advice would be to get after it ASAP! Clots can be life-threatening if the clots travel to the lungs/heart.