Diabetes and Radiation

I finished my chemotherapy (Taxotere and Cytoxan 6 rounds) and my radiation. Hooray! My last radiation treatment was a week and a half ago. I did some research and asked for a shorter, higher dose three week course of radiation. They call it the Canadian Protocol. They said that I had very good results and fewer than average side effects.

I called Minimed about using the continuous glucose monitor (CGM) while undergoing radiation therapy. The continuous glucose monitor is a fairly new device for people with type I diabetes. It automatically checks your glucose levels every five minutes and sends you signals if your glucose is too high or too low.

Apparently no one has asked the manufacturer (Minimed) about this before so I guess I was test subject #1. They have had people with insulin pumps get radiation therapy but not anyone with a pump and a CGM.  

The transmitter is very sensitve to radiation, so I had to remove it off before each dose of radiation. I would disconnect my pump and my CGM transmitter in the car when I parked outside the facility where I got the radiation. ( I would hide it under my chemotherapy wig in the front seat of the car.) It did mean unzipping my pants in the front seat of the car, but early in the morning, there were not a lot of people around.

We were not sure about the sensitivity of the implanted sensor to radiation. Initially, I put the sensor in my thigh to keep it far away from the radiation field. I managed to get a rather impressive bruise when I hit a large blood vessel in my thigh. After some trouble with the insertions of the CGM in the thigh, I called Minimed again and ended up using my lower abdomen. The radiation people put a lead shield over the sensor. The shield might not be necessary, but we were playing it safe since no one has done this before.

After I got the radiation each morning, I would go back to the car, and reconnect everything. You have to re-start and recalibrate the CGM each time after you disconnect the transmitter.  This meant that I would lose data for a couple of hours after each treatment. .

The sensors seemed to work well except for when they pulled out from the multiple times I had to remove the tape. I used more insulin during the radiation theapy. I am not sure of this, but it seemed that I needed more basal and bolus insulin in the morning (I got my radiation at 7:30am) and less in the afternoon. the variations in insulin use were not as dramatic as the variations I experienced when I was on the chemotherapy.

Now that I am finished with the main part of my treatment for the breast cancer, I have to take a hormone pill daily for five years. It is an aromatase inhibitor. I got through menopause without any hot flashes. This medication reduces estrogen levels even lower than menopause, so I am now  finally having the joy of hot the hot flashes that I never had during menopause. Actually they are not so bad. I just keep my office cool and wear cotton. My insulin requirements are going down. They are still higher than before I started treatment, but I am hoping that they will be back to baseline in a few weeks once my body is adjusted to the end of the radiation treatment.

If anyone else has breast cancer and takes insulin, please contact me.  

Carol