Lower Platelet count after HDR Brachytherapy

[PopCubby]

I am 76 and have had a low platelet count for at least the past 30 years. My results had usually been in the 125,000 range, with 140,000 to 150,000 being the minimum value to be considered normal.

I had HD Brachytherapy for prostate cancer in November 2021, and ever since then my platelet count has dropped to around 105,000. I don't have any issues with bruising or bleeding, but my primary care physician is concerned that the recent drop may be an indicator of another problem; possibly spread of my cancer.

I follow up with the radiation oncologist and urologist every 6 months, and my PSA was <0.1 in April, but I don't think they are aware of my platelet count results, so this has never been an issue.

I am wondering if anyone else, who has had radiation treatment, has experienced a drop in platelet count. I have read that radiation can sometimes cause a low platelet count, but couldn't find anything directly related to Brachytherapy for prostate cancer.

[Tall_Allen]

Did you have Brachy Boost Therapy (with whole pelvic external beam therapy) or just monotherapy? Depression of bone marrow is a known side effect of whole pelvic radiation.

[PopCubby in reply to Tall_Allen]

I did not have the Boost external beam therapy. Just 2 treatments of Brachytherapy, a week apart.

[Tall_Allen in reply to PopCubby]

You can ask your RO what the dose to pelvic bones and femur were on the dose/volume histogram.

[PopCubby in reply to Tall_Allen]

Thanks. Will do.