Randomized Adjuvant Trial to Evaluate the Addition of Tamoxifen and PSK to Chemotherapy in Patients with Primary Breast Cancer

Authors: Masakazu Toi, Takao Hattori, Masanobu Akagi, Kiyoshi Inokuchi, Kunzo Orita, Keizo Sugimachi, Kiyohiko Dohi, Yasuo Nomura, Yasumasa Monden, Yuzo Hamada, Tadaoki Morimoto, and Nobuya Ogawa

Journal: Cancer

Study Design: Randomized adjuvant trial

Participants: 967 patients with operable Stage IIA, IIB, and IIIA primary breast cancer

Trial Length: 5 years

Intervention:

• ER-positive tumors: Patients were randomized to receive mitomycin C (MMC) + ftorafur (FT) with or without tamoxifen (TAM).
• ER-negative tumors: Patients were randomized to receive MMC + FT with or without PSK (a biological response modifier).

Primary Outcomes: Overall survival (OS) and relapse-free survival (RFS)

Summary: The study investigated the impact of adding tamoxifen (TAM) to chemotherapy in patients with estrogen receptor (ER)-positive breast cancer and the addition of PSK to chemotherapy in patients with ER-negative breast cancer. The results showed that adding TAM significantly improved OS and RFS in patients with ER-positive and Stage IIIA T3N0 breast cancer. However, no significant survival benefit from TAM was observed in patients with ER-positive and Stage IIA T2N1 breast cancer. In patients with ER-negative disease, there was no significant difference in outcomes between the regimens with or without PSK. Subset analyses suggested potential benefits of TAM in postmenopausal patients with ER-positive and Stage IIA T2N1 cancer and of PSK in patients with node-negative, ER-negative, and Stage IIA T2N1 cancer. The 5-year results indicate a survival advantage with the addition of TAM to chemotherapy in patients with ER-positive and Stage IIIA T3N0 breast cancer.