# TAM-01

Source: https://onco.cc/trials/tam-01/  
OnCo record `tam-01` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

TAM-01 showed that a quarter of the usual tamoxifen dose, taken for three years, roughly halved the risk of a new or recurrent breast cancer after treatment for DCIS or other pre-invasive changes, with far fewer of the side effects that make women stop the full dose.

## Summary

Tamoxifen at 20 mg daily prevents recurrence after ductal carcinoma in situ but hot flushes, endometrial cancer and thrombosis limit its use. TAM-01 was an Italian phase 3 trial that randomised 500 women with breast intraepithelial neoplasia (atypical ductal hyperplasia, lobular carcinoma in situ or oestrogen receptor-positive or unknown ductal carcinoma in situ) to tamoxifen 5 mg daily or placebo for three years. The primary endpoint was the incidence of invasive breast cancer or ductal carcinoma in situ.

Low-dose tamoxifen roughly halved the rate of breast events, including contralateral cancers, with no significant excess of endometrial cancer or venous thrombosis and only a modest increase in hot flushes. The benefit persisted in longer follow-up. Low-dose tamoxifen is now offered as an alternative for women who cannot tolerate the standard dose.

## Fields

- Kind: Trial
- Status: positive
- Last checked: 2026-09-17
- Tags: subtype-trials
- Registry id: NCT01357772
- Phase: 3
- Setting: Breast intraepithelial neoplasia (atypical ductal hyperplasia, lobular carcinoma in situ or hormone-sensitive ductal carcinoma in situ) after surgery: low-dose tamoxifen 5 mg daily for three years against placebo
- Sponsor: Andrea DeCensi, Galliera Hospital, Genoa
- Enrolled: 500
- Result: Tamoxifen 5 mg daily for three years roughly halved breast cancer events compared with placebo with few serious adverse effects.

## Sources

- ClinicalTrials.gov NCT01357772: https://clinicaltrials.gov/study/NCT01357772

## Connected records

- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [Ductal carcinoma in situ (DCIS)](https://onco.cc/cancers/ductal-carcinoma-in-situ/)
- drugs: [Tamoxifen](https://onco.cc/drugs/tamoxifen/)
- people: [Andrea DeCensi](https://onco.cc/people/andrea-decensi/)

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