Diabetes, insulin and breast cancer

sweetlady2

Diabetes, insulin and breast cancer

sweetlady2

I was recently diagnosed with T1c estrogen positive, Elston Grade II, node negative IDC. I also happen to have well-controlled Type I Diabetes, using an insulin pump and a continuous glucose monitor. Depending on a few more tests, they may recommend chemo before the radiation. Anyone else been through breast cancer treatment while on insulin?

sweetlady2

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. Apparently no one has asked them 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 CGM.

The transmitter is very sensitve to radiation, so you need to take it off before you get the radiation. I would disconnect my pump and my CGM transmitter in the car when I parked outside the facility where I got the radiation. 

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. 

Occasionally the implanted sensor would pull out when I removed the tape. This meant that I went through more than the usual number of sensors each week. Luckily insurance was covering the sensors. Since I generally get more than three days out of each sensor, I had enough extra sensors to  make up for the extra ones that I used during radiation .

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.

 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. 

Carol  

sweetlady2

I finished my radiation (used the Canadian protocol--only 3 weeks!) and then started Arimidex. The Arimidex caused some hot flashes and bone pain but nothing that would make me want to stop it. Unfortunately for me there was another apparent side effect--it seems to have affected my glucose control. I am not completely sure tha tthe Arimidex is the culprit--I supposed that it might be a long term side effect of the chemotherapy--but my glucose was better when I temporarily stopped the Arimidex for three weeks. The bone pain and the hot flases went away too. My oncologist put me on another amomatase inhibitor, Aromasin. The bone pain and the hot flashes are much better than with the Arimidex, but I had another bad hypoglycemic episode.  Even with the continuous glucose monitor, my sugars jump around.   I have had to arrange my work schedule so that I have more breaks so that I can check my blood glucose a lot.

My tumor was 95-100% estrogen positive, so I am probably stuck with the aromatase inhibitors, but I think that they affect glucose control. Unfortunately there is minimal published data on this subject.