From the Guidelines
Low-dose Tamoxifen is effective in reducing the risk of recurrence in patients with Ductal Carcinoma In Situ (DCIS).
Efficacy of Low-Dose Tamoxifen
- The TAM-01 trial showed that low-dose tamoxifen (5 mg daily) decreases the risk of recurrence after DCIS 1.
- A recent randomized trial in women with intraepithelial neoplasia, including DCIS, found that low-dose tamoxifen (5 mg/day) reduced the risk of breast cancer relative to placebo, with a 50% reduction in neoplastic breast events (DCIS or invasive cancer) 1.
- The results of low-dose tamoxifen are consistent with the effect of 20 mg/day of tamoxifen in the NSABP-B24 subgroup analysis of hormone-sensitive DCIS, with a hazard ratio of 0.58 (95% CI, 0.42 to 0.81) 1.
Clinical Considerations
- Low-dose tamoxifen may be an alternative for women with intraepithelial neoplasia, including DCIS, who are concerned about adverse effects, as it was not associated with an increase in serious adverse effects, including deep venous thrombosis and endometrial cancer 1.
- The incidence of hot flashes was slightly higher with low-dose tamoxifen than with placebo, although trial adherence was similar 1.
- The panelists at the St Gallen International Consensus Conference recommended considering low-dose tamoxifen (5 mg) for prevention of recurrence and secondary cancers in patients with low-risk DCIS 1.
From the FDA Drug Label
Tamoxifen citrate tablets are indicated to reduce the risk of invasive breast cancer in women with DCIS, following breast surgery and radiation The recommended dose is tamoxifen 20 mg daily for 5 years A large U. S. study looked at women with DCIS and compared those who took tamoxifen citrate tablets for 5 years with others who took a placebo Out of every 1,000 women with DCIS who took placebo, each year about 17 got breast cancer Out of every 1,000 women with DCIS who took tamoxifen citrate tablets, each year about 10 got breast cancer The study showed that on average, women with DCIS who took tamoxifen citrate tablets lowered their chances of getting invasive (spreading) breast cancer by 43%, from 17 in 1,000 to 10 in 1,000 2
The efficacy of low-dose Tamoxifen for Ductal Carcinoma In Situ (DCIS) is a 43% reduction in the risk of invasive breast cancer, as shown in a study where women with DCIS took tamoxifen citrate tablets for 5 years. The recommended dose for this indication is 20 mg daily for 5 years.
From the Research
Efficacy of Low-Dose Tamoxifen for DCIS
- The efficacy of low-dose Tamoxifen for Ductal Carcinoma In Situ (DCIS) has been investigated in several studies 3, 4, 5, 6, 7.
- A randomized placebo-controlled trial found that low-dose Tamoxifen (5 mg once daily) for 3 years reduced the recurrence of invasive breast cancer or DCIS by 52% without additional adverse events over placebo 4.
- A meta-analysis of two randomized trials found that Tamoxifen added to radiotherapy and surgery reduced overall breast cancer recurrence by 29% in all patients and by 33% in those treated with both surgery and radiotherapy 6.
- Another study found that low-dose Tamoxifen significantly decreased any breast event (HR = 0.70,95% CI: 0.54-0.91) and ipsilateral DCIS recurrence (HR = 0.66,95% CI: 0.49-0.88) in ER positive DCIS patients 7.
- The benefit of low-dose Tamoxifen was found to be independent of age, with both young and older women achieving some benefit from the addition of Tamoxifen to surgery and radiotherapy 6.
Reduction in Recurrence
- Low-dose Tamoxifen has been shown to reduce the risk of recurrent DCIS, with a significant 50% reduction of recurrence in the DCIS cohort 4.
- Tamoxifen has also been found to reduce the risk of contralateral invasive cancer, with a hazard ratio of 0.36 (95% CI: 0.14-0.92) 4.
- The number needed to treat to prevent one case of breast event with Tamoxifen therapy was found to be 22 in 5 years and 14 in 10 years 4.