Tamoxifen - can it cause pelvic discomfort

wheatfields

I am taking Tamoxifen being a second choice over Aridimex because of my already low bone density. I have a mild cramp like feeling in the low pelvic area after about 10 days of taking Tamoxifen but don't really read that anywhere in it's "side effects". I did go in to my gynecologist who says everything looks fine and not to worry, but it could be the Tamoxifen since it's a estrogen blocker. However, I'm thinking 5 years of a mild feeling of pelvic discomfort? Does anyone else have this kind of side effect?

gb2115

I get that but I think I get cysts that come and go.

sm627

Hi Wheatfields,

I have been on Tamoxifen for 2 years and have had the pelvic discomfort you are talking about. For me it has felt like mild period cramps, but everyday and not just around my period. I too talked to my GYN and she said that it could be Tamoxifen because of the extra estrogen it gives the uterus and ovaries. What she suggested to help with the pain/ discomfort is a heating pad which has worked for me. However the discomfort became to annoying/painful for me because it never went away, so I talked to my MO and asked if I could lower my dosage to 10mg instead of 20. She said yes! I have been taking 10mg for about a month now and have noticed a big differences the pain has decreased a lot and I am finally starting to feel better.

How often do you feel the pelvic discomfort and do you have any other side effects? I hope you are able to find something to help reduce your discomfort.

Hugs,

Sara

wheatfields

Thank you so much for the suggestions Sara. I will try the heating pad and also ask about 10 mg instead of 20. That is 10 mg once a day isn't it. Not 10 mg twice a day? I feel the pain/discomfort off and on through most every day, and like you said it is mostly "annoying". One thing my MO told me was that most women take it in the evening and I was taking it in the morning simply because it seems easier to remember then. So last night I switched to evening to see if that by chance helps. I'm not noticing any other side effects except a light clear discharge which I was told is normal with Tamoxifen. I forgot to mention I'm 67 and so am not used to a "period" type of discomfort anymore Thank you again for your reply!

flashlight

Hi wheatfields, I am 68 and had those period like cramps and pelvic pressure. One of the side effects of Tamoxifen is a thickened endometrium which can cause those cramps. I had a baseline vaginal ultrasound and that showed a thickened lining and a large fibroid. They were unable to do a biopsy in the office so I had a D&C last August. As it turned out they think the Tamoxifen started to feed the fibroid and the fibroid gave a false reading about the thickness of my lining. I had only been on the Tamoxifen a short period of time. They were able to remove that fibroid and the biopsies came back negative. I no longer have that crampy feeling. I haven't talk to my MO yet, but I decreased my dose to 10mg a day. I am considering a hysterectomy in the new year.

wheatfields

Thank you! I am beginning to understand this better. I did have that vaginal ultrasound the other day and she saw nothing out of the ordinary, she did mention a thicker endometrium. I seriously wonder if the 10 mg might do the trick. I have only been on the Tamoxifen 20mg since September 1st. Am anxious to ask about the 10 mg. Thank you again !

sm627

Hi Wheatfields,

Well aren't you lucky to have not have to deal with periods anymore. :-)

I take 10mg once a day. I know some people take it twice day am/pm. I haven't tried that yet. The 10mg pills are much smaller than the 20mg. I have be taking my Tamoxifen at night, so I could deal with the side effects or try to sleep it off. I found that movement helped a lot with the discomfort during the day even just walking was a good distraction. The heating pad helped me sleep at night.

I know tamoxifen is supposed to help us, but sometimes I wish it would just take care of the boob situation and not mess around causing chaos with the rest of our body. :-(

Any way hope things get better and that you have good day. I'm about to head out to the farmer's market. Hope you do something fun today.

Take Care,

Sara

Legomaster225

I had mild/moderate discomfort in my abdomen while on tamoxifen. I had regular periods that ended with chemo but I was 50 so probably close to menopause. I ended up having two vaginal ultrasounds with d & c's after both due to thickened endometrium. It wasn't working for me. Perhaps your discomfort is similar?

I ended up switching to Aromasin after less than a year on tamoxifen. I have osteoporosis (Discovered on my baseline test prior to switching) and now am on getting Reclast. I have not had a second dexa scan yet to see if it helped. Hope you find some answers soon. Maybe the switch to 10mg will make the difference

Euphoriaa

I noticed a big swelling in my belly from the first pill. I reduce it on my own without asking my MO, I had no more problems since then (almost two months ago)

wheatfields

Hoping that everyone has a wonderful Thanksgiving! I did ask about the 10 mg instead of 20 mg and the MO said to come in January and we would "discuss" the options. So I'm not sure that is going to be a possibility in his mind. I had two days with a lot of pelvic discomfort and now the last two days were really pretty good, don't understand that at all. But you are right about movement, i.e. walking, or exercise and the heating pad do help. I've also read that 10 mg is as effective as 20 mg and another thought I've had, is because I weigh 120 lbs, maybe 20 mg is simply too much A blessed Thanksgiving to all!

Take care,

Wheatfields (covered with snow)

wheatfields

The answer at the MO was no regarding taking 10mg a day, so I switched to 10mg twice a day to see if that helps. Had a few good days free from cramps but not today. Not sure whether this will work or not. I was thinking does anyone ever have their uterus removed? Wouldn't that solve that problem?

Wheatfileds

DorothyB

Wheatfields, two thoughts:

1) Not saying it is OK to take only 10 mg, but YOU are the one who gets to make the final decision. I am opting to take only 10 mg and my Kelsey MO was very upset with me, etc. I went to another MO today (with MD Anderson). I get along much better with him. He does want me to take 20 mg, but said that he would rather I would take 10 mg than none.

2) Where did you read that 10 mg was as beneficial as 20 mg? I've only found two "studies". Copying from a post I did a couple of weeks ago:

Today I found this: https://academic.oup.com/jnci/article/95/11/779/25... which includes "Background: Tamoxifen reduces the risk of breast cancer in women at high risk for the disease but increases the risk for endometrial tumors and venous thromboembolisms, possibly in a dose-dependent fashion. We compared the effects of tamoxifen at 1 mg/day and 5 mg/day with those of the standard dose of 20 mg/day on breast cancer proliferation using a surrogate endpoint marker (Ki-67 expression) and blood biomarkers associated with breast cancer . . . . Methods: We randomly assigned 120 women with estrogen receptor (ER)-positive breast cancer to tamoxifen at 1, 5, or 20 mg/day for 4 weeks. Expression of the tumor proliferation marker Ki-67 and of biomarkers of breast cancer (insulin-like growth factor-I, sex hormone-binding globulin) . . . risk were determined before (baseline) and after treatment. All levels were compared with those in two nonrandomized control groups (34 women with ER-negative breast cancer and 29 additional women with ER-positive breast cancer). . . . Results: Expression of Ki-67 decreased in all three tamoxifen groups, with no difference in the magnitude of reduction among groups . . . Relative to baseline, Ki-67 expression decreased by a median of 15.0% . . . among the tamoxifen groups but increased by 12.8% . . . among the nonrandomized control groups. Several blood biomarkers showed dose–response relationships with tamoxifen, including decreased insulin-like growth factor-I, increased sex hormone-binding globulin . . . levels. Conclusions: The effects on Ki-67 expression of lower doses of tamoxifen were comparable to those achieved with the standard dose, although the effects on blood biomarkers were variable. The effects of lower doses of tamoxifen should be assessed further in randomized trials."

I'm happy to see another study that says that less than 20 mg / day might be effective for those of us with stage 1 cancer.

However, the previous study that I've linked before https://www.researchgate.net/publication/12740517_... had slightly different results. This link includes "Tamoxifen administered at 20 mg/d has been shown to decrease breast cancer incidence in at-risk women by 50%, but toxicity may limit its broad use, particularly in postmenopausal women. Because toxicity may be dose-dependent, we studied the biologic activity of low concentrations of tamoxifen to determine the plausibility of a dose reduction. We measured the blood concentrations of tamoxifen and its main metabolites in a dose titration study in 105 healthy women (placebo, tamoxifen 10 mg on alternate days, tamoxifen 10 mg/d, and tamoxifen 20 mg/d). Drug levels measured after 2 months of treatment were correlated with the changes in surrogate biomarkers of different diseases, including . . . insulin-like growth factor I, a promising surrogate biomarker of breast cancer. The means . . for tamoxifen and N-desmethyltamoxifen (metabolite X) concentrations (ng/mL) were dose-related, being, respectively, 0 and 0 with placebo, 26.8 +/- 15.1 and 43.7 +/- 22.5 with 10 mg every other day, 51.2 +/- 24.1 and 90.7 +/- 48.0 with 10 mg/d, and 136.0 +/- 52.7 and 230.6 +/- 75.0 with 20 mg/d of tamoxifen. At variance, the biomarker changes were of comparable magnitude at any drug concentration . . . . An 80% reduction in blood concentrations does not seem to affect the activity of tamoxifen on biomarkers of . . . breast cancer risk and may in fact have a more favorable safety profile. Additional studies are warranted to determine the most appropriate dose of this agent.

My reading of the second study seems to indicate that decreasing the dose of tamoxifen does not decrease the change in the breast cancer biomarker "insulin-like growth factor I" but the first study said "Several blood biomarkers showed dose–response relationships with tamoxifen, including decreased insulin-like growth factor-I . . . levels."

Curious if Beesie or anyone else has anything to add to my understanding of these two studies?

Thanks!

wheatfields

Hello Dorothy,

I just googled "tamoxifen 10 mg vs 20 mg and came up with some articles. One was from https://www.webmd.com › Breast Cancer › News and the other one that you just posted. The MO was giving me some percentages of recurrence risk if one went down to 10 mg. I guess I'm scared yet to do it. I should probably be thankful I only seem to notice the pelvic cramps so far and not other side effects many others have mentioned. Right now I'm trying the 10mg morning and evening. For a few days I thought that was better except today it seemed to catch up with me. One of the ladies on the forum mentioned that her MO had said that was fine to take 10mg a day. Maybe some factors are the initial diagnosis, ie. stage, grade, positive or negative? Thank you for your thoughts and take care!

Wheatfields

WC3

I had a mild, cramp like heavy feeling for a few months after starting Tamoxifen. It eventually went away.

wheatfields

WC3,

Thank you for sharing, that is good to know! I'm only in the 4 month of Tamoxifen.

Take care!

Wheatfields

DorothyB

Wheatfields - I tried to find the article you mentioned but couldn't. Your link only went to webmd and I searched there and didn't find anything.

wheatfields

When I googled Tamoxifen 10 mg vs 20 mg, that was one of the articles that came up.

https://www.webmd.com/breast-cancer/news/20181206/...

Let me know if that works.

Wheatfields

DorothyB

Wheatfields - yes that worked. Thanks!

I saw a new med onc this week and really liked him. Without pushing me, he actually had me considering trying to go back above the 10 mg again, but this study while not on actual stage 1 breast cancer patients sounds very promising!