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Low White Blood Count? Freaking out


I am more than six months past chemo and two months out of radiaiton.

I have been taking letrozole (Femara) for five weeks.

I have been having a little lightheadedness, which I reported to my MO because it's not uncommon with AIs.

At the same time, my PCP was doing my annual blood work, and my WBC is down to 2.7. (The bottom of the range is 3.4.) She sent me a note saying everything was normal. I just happened to notice myself that the lab company flagged it as low.

A month after chemo, my WBC was 3.7. Before cancer, back in 2015, it was 4.8. So, clearly I don't have a typically high count. But still.

AIs don't cause low white blood counts, right?. What could cause it? I'm freaking out about chemo-induced leukemia or MDS or a blood clot or I don't know what.

I see the MO's PA on Monday, but there is not enough Xanax in the world to help me make it until then.



  • Michelle_in_cornland
    Michelle_in_cornland Member Posts: 1,233
    edited February 2017

    The effects of bc treatment are cumulative. You just finished radiation and are taking letrozole. Letrozole can cause low wbc. Now that you know you are on the lower side, you can just be aware and do whatever you can to raise it. I did no have chemo, but imagine it is a matter of time for things to "settle down" in your body. Eating healthy, upping your red blood cell count, exercise and hydration should all yield benefits. Someone else with more knowledge of your situation will chime in soon. Don't let your mind wander. Work on a small project to keep yourself occupied.

    Femara Side Effects


    Common side effects of Femara (Letrozole) include weight gain, joint pain, light sensitivity, disorientation, headaches, dizziness and vomiting. Aromatase drugs are those medications that are used in the treatment of breast cancer and ovarian cancer in females, which can help prevent cancer. Aromatase is what synthesizes estrogen, an essential hormone for women.

    Common Femara Side Effects

    Certain common Femara side effects can occur in some patients. Do not hesitate to contact your doctor if you display any of the following symptoms after taking Femara:

    • Joint pain
    • Nausea
    • Weight decrease
    • Weight gain
    • Skin sensitivity
    • Headaches
    • Dizziness

    Most of these side effects are temporary, if they occur in the patient at all. The side effects can be severe, however, if women who are pre-menopausal begin taking Femara. It is not usually prescribed to women in this age range unless they are producing an excess of estrogen.

    Serious Femara Side Effects

    femaraThe side effects of Femara can be very serious in some cases. This usually only occurs if the patient deviates from their prescribed dosage or suffers from an allergic reaction to the drug. If any of the following side effects sound like something you have experienced, contact your healthcare professional immediately:

    • Fatigue
    • Dizziness
    • Drowsiness
    • Decreases in white blood cell counts
    • Increase in cholesterol
    • Decrease in bone density
    • Weakness
    • Irregular pregnancy

    The following side effects are not necessarily associated with an allergic reaction, but still should require medical attention:

    • Extreme Weakness
    • Disorientation
    • Nausea
    • Vaginal Irritation
    • Blood clots
    • Heart Attack
    • Endometrial Cancer
    • Bone fractures
    • Osteoporosis

    As with any of the other side effects, these symptoms can be a sign of a more serious, underlying health issue. Please contact a healthcare professional if you display any of the above signs. Doing so can prevent permanent damage or, in some cases, death.

    Femara and Impairment

    Letrozole may induce severe adverse symptoms in those who are hypersensitive to the drug. In some extreme cases, impairment or permanent damage may occur. Such damage may include blood clots, heart attacks, forms of cancer, bone weakness, fractures, and inability to operate machinery due to disorientation and dizziness and pain in the extremities. Although the medical significance of white cell blood count loss is not known, it is also one of the bolder side effects.

    Patients may also experience sudden weight decrease while taking Femara. The rise of cholesterol in the blood gives rise to the chance of contracting a heart attack.

    Other Medications

    Femara is often combined with other medications, but there are a few prescriptions that should never be mixed with Letrozole. One of these drugs is Birth Control. Birth Control pills contain estrogen, which Femara works to inhibit.

    Some drugs that will interact with Femara are conjugated estrogens, anastrozole, tamoxifen, ethinyl estradiol, and any drug that contains any trace of estrogen. You should also inform your doctor about any prescription drugs, herbal products, or non-prescription drugs that you are taking before you begin consuming Femara.

    Femara in the Elderly

    Femara is not often used in the treatment of elderly patients. Older women do not produce as much estrogen as those who are newly post-menopausal, but there are always exceptions to such cases. Limiting the production of estrogen in an elderly female can result in many of the same side effects as previous listed. However, side effects tend to be more violent in the elderly. Such indications of an adverse reaction include pain, swelling, vision changes, dark urine, vomiting, slurred speech, weakness on only one side of the body. Chest pain, jaw pain, pain in the upper areas of the left or right arms, numbness, skin sensitivity, and swelling of the throat, tongue, and cheeks.

    Femara and the Liver

    Femara side effects may affect the liver. This specific organ does not particularly welcome any synthetic medication, and all wreak a certain amount of damage on the liver. Taking Femara over a prolonged period of time may cause liver toxicity. It is important, therefore, to compliment Femara consumption with eight to ten glasses of water every day. Liver or kidney failure is also a risk when taking Femara.

    Femara side effects are usually few and far between. However, in the event that you experience any of the above symptoms, do not hesitate to seek medical attention immediately.

    Source: Femara Side Effects (Letrozole) -

  • AnotherMichelle
    AnotherMichelle Member Posts: 3
    edited February 2017

    Michelle in Cornland, thank you. I swear I have looked at 20 different sites listing the side effects of this drug, and none of them are the same, and I had not seen this one or seen any of them mention WBC. And how can a side effect (dizziness, say) be both "Common" and "Serious" at the same time? (That's a rhetorical question. I'm just expressing frustration.)

    I so appreciate your time tonight. You have been a light in a dark and scary time for me.


  • KBeee
    KBeee Member Posts: 695
    edited February 2017

    Radiation can lower white counts too

  • Michelle_in_cornland
    Michelle_in_cornland Member Posts: 1,233
    edited February 2017

    The common and serious depends on why you are experiencing the dizziness. You are going to get through this and call your doctor on Monday. In the meantime, visit my thread called...Uplifting and Positive Messages.....under the hormonal section. Hang in there. ThumbsUp

  • yellowb
    yellowb Member Posts: 102
    edited June 2019

    I'm having the same from Tamoxifen -- another known but rare SE. I got through dd Taxol and AC without blood counts anywhere near this low!

  • wised
    wised Member Posts: 184
    edited June 2019

    I finished chemo 3 years ago for colon cancer and my white blood count is still only 2.5. My oncologist is not at all concerned about it.

  • lrubenstein
    lrubenstein Member Posts: 1
    edited November 2021

    THANK YOU so much for this post. I am 2.5 years on aromatase inhibitors and again my WBC is low. A year ago it was down to 3.3 and when I brought the issue up to my oncologist he said it could be a problem with my bone marrow which is not curable and fatal. He suggested I go off the anastrozole for a month to see what happens. It was a month from hell, but my WBC when up to 5.1. He said it was not the bone marrow and he put me on exemestane which gave me insomnia, so then I went on to letrozole. During my last visit to the oncologist, he noticed my WBC was 3.2. AGAIN he said it could be terminal bone marrow issue or it could be a liver issue. WHAT?? Now I'm freaking out again and back on the Xanax. I think it's the Letrozole. But he is running blood tests and is suggesting a liver scan and a bone marrow punch test. This is so frustrating and frightening. But this post let me know that others are having this issue with aromatase inhibitors. I'm willing to live with a low WBC for another 2.5 years, but I can't keep going through this fear. It's bad enough that my cancer was in the high category for returning without adding more stress to my life.

  • cbk
    cbk Member Posts: 323
    edited November 2021

    I am just about 4 years out post final chemo ACT regime and my WBC has been consistently low. It toggles btwn 3.8 to 4.0. But earlier out of chemo it was even lower.

    Most likely a product of Arimidex consumption. I even sought a second opinion from a hematologist at a top cancer center who ran extensive blood work on me to find nothing. He said if you aren’t experiencing symptoms of compromised immune system just don’t worry about it.

    I just got my 6month follow up bloodwork from Oncology and it’s yep..3.8 again.

  • margun
    margun Member Posts: 385
    edited January 2022

    CBK- what your oncologist said about your 3.8wbc. I Have low wbc and rbc also. I

    finished chimio 2.5 years ago. I was diagnosed January 2019 with triple positive ductal grade 3 1.5 Cm tumor no positive nodes. Chimio ac &taxol then goldilocks mastectomy. Since October 2019 on Letrozole. After bc my wbc and rbc was always borderline low but the latest was even lower than the normal range 3.9wb and 3.88rbc. Someone told me that letrozole can reduce wbc. I prefer that from recurrence but what if letrozolés damage to wbc continues?My doc appointment is in 8 days. I hope by then I hear your opinions I am worried . Thanks

  • threetree
    threetree Member Posts: 1,471
    edited January 2022

    Margun - I responded under the "Femara" thread.