I found the attached documents from BC Cancer agency internet and want to share.
I wish I found the links earlier. (10 years after her 1st time breast cancer) My mom first felt abnormal tired and was diagnosed anemia by her young family doctor. She prescribed iron injections for my mom and said no side effect, excess iron would get out of body automatically through bowel movement. After 1st time injection, my mom felt pain and her stomach grew quite a lot but all these symptoms subsided in few days. 2 weeks later after the 2nd injection, my mom felt so much pain and her stomach grew like a balloon. We took her to emergency, physician found serious blockage in the colon and immediate surgery. Metastatic to colon and surrounding blood vessels. A large tumor at colon wall was removed but a tennis ball size on nearby blood vessel was inoperable. Though my mom lived a good 2 years after surgery , I am still thinking if there was no those iron injections, the tumors might not be so exaggerated in only a few days and chemo might extend her life for bit longer.
ps. the older version has more information on Anemia