2 months on Orgovyx and Zytiga - 60% through radiation

For me, during chemo treatments, my white blood cells would drop, but come up some when it was time for next treatment. I'm not sure how often you get tested, I was tested once a month. Yes, you have to be aware that you are susceptible to infections, so you need to act accordingly. Best to you.

My friend took a lot of precautions when he was on chemo for lymphoma, but his immunity seemed to come back quickly every time. It was during the COVID emergency, so he took all the recommended precautions (most of them also make sense for avoiding flu, colds, or even mpox).

I’m also a stage 3 PCa patient. I had the exact same thing when I went thru radiation. I never had an issue with infection.

Good luck on your journey.

I was interested in this as well when my first lymphocyte count came back at 710 /μL ("grade 2" lymphopenia). This was halfway thru RT and I asked the doctor on site about it. He told me, it is so common they don't test for it.

In a new test yesterday it was 490 (borderline Grade 2/3). My doctor told me there was nothing to worry about at 710, anything above 500 is fine 🙂

From a paper on the subject:
Radiation-induced lymphopenia (RIL) has long been observed in radiation therapy patients (1–3) and develops in up to ~70% of patients undergoing external beam radiation therapy (4–8).

I found this in one study:
Lymphocyte LD50 (lethal dose required to reduce the surviving fraction of lymphocytes by 50%) is 2 Gy and LD90 (lethal dose required to reduce the surviving fraction of lymphocytes by 90%) is 3 Gy (Nakamura et al., 1990).
Given I had 65 Gy dose, it is hardly surprising a few were killed 🙂

You may be interested in this Danish study https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6211632. In here you can see the elevated risk of infection (Fig 4) and death from infection (Fig 9) vs lymphocyte count.

In my case it seems I have a 1.8 times higher chance of infection and 2.5 times higher chance of death once infected compared with what I had before. (this is my interpretation of the graphs, please correct me if I am wrong)

Another older retrospective study found no increased risk (but the Danish study was probably of higher quality). I can find the older study if you are interested.

Unfortunately, from what I understand, it will take a few years to get back to normal, so I plan to be a bit careful.

You’ve done quite a bit of research on this - thanks for sharing. My measurements are different in that they’re .32 10*3/ul. I’m unaware of how this translates into the levels you noted

Here’s my table of results
Aug 15, 2024
0.3210*3/uL
Jul 11, 2024
0.9210*3/uL
May 23, 2024
1.2110*3/uL
May 2, 2024
1.210*3/uL

Any further thoughts? Thanks

Blood cells are measured in number per volume. Mostly it is count per micro-litre (which is a pretty small volume), I guess your lab is giving the figures with a multipler. Are all you figures formatted OK – maybe 1200, 1200, 920 and 320?

If 0.3210*3/uL is
0.32 x 10^3 lymphocytes per microlitre (=300 per microliter). I had a superscript for the 3 but it was removed when I posted 🙁
(uL is microlitre, also µL or mcL)
What are their reference ranges at you lab? Mine gives 1200-3500. (=1.2 x 10^3 - 3.5 x 10^3)

In the previous study I posted before they use “count per nanoliter” which is a thousand times smaller so the count in your case that would be 0.3.

As to actual risk of infection – I’m not sure – studies are contradictory. Personally, I will be a little more cautious but won’t worry too much about it.
I have a followup appointment (6 weeks post RT) next week and intend to discuss it then (with my new results).
I suggest you talk with your Doctor, but the two I have asked were pretty relaxed about it (at 710).

This study says in the conclusions (and is PCa specific) that there was no additional risk.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9375833/
As a result, there is no significant difference between those that did and did not have radiation. Immunocompromised patients are known to have an increase in opportunistic infections. We could detect no long-term difference in opportunistic infection between those that did and did not receive radiation. We have shown that pelvic radiation has minimal lasting effects on lymphocyte and granulocyte counts. In addition, patients receiving radiation do not appear to be significantly immunocompromised.

However this one found some additional risk. Typical contradictionary conclusions 🙂
This study does have a good graph of lymphocyte count over time which I had not seen elsewhere, but I did not understand their second graph at all (nor how they reached those conclusions)!
https://academic.oup.com/ofid/article/4/suppl_1/S702/4295665?login=false

The lab has a reference range of 1.1 - 2.7. Based on the information you provided and the fact that my radiation oncologist has stated he’s not alarmed I’ll be cautious but not alarmed. I’ll see the medical oncologist in two weeks and ask him his thoughts. Thank you for the information

In case it's helpful, my lymphocytes (measured in 10^9/L) dipped to 1.1 a month after 20 sessions of SBRT to my prostate (total 60 gy), but were back at the bottom of the normal range 3 months later, and had recovered to their normal, pre-radiation level 6 months after treatment.

My lab's expected range was 1.2–4.0 10^9/L

Yeah I think it's not a big issue, this is helpful to understand the (absolute) risk rather than the relative risk (2 * a small risk is not a big deal for example).

In my case 63 years old, male and non smoker. My risk of hospitalisation in the next 2 years with an infection is 3 in 100. With my grade 2/3 lymphopenia (490/mcL) it is 7 or 8.