Breast cancer survival and incidence of second primary cancers after 30 years in a randomized study of two versus five years of adjuvant tamoxifen therapy
Anna Nordenskjöld,
Helena Fohlin,
Johan Rosell,
Nils-Olof Bengtsson,
Tommy Fornander,
Thomas Hatschek,
Henrik Lindman,
Per Malmström,
Lisa Rydén,
Arne Wallgren,
Olle Stål,
Bo Nordenskjöld
Affiliations
Anna Nordenskjöld
Department of Medicine and Oncology, Southern Älvsborg Hospital, 50182, Borås, Sweden; Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy, Sahlgrenska University Hospital, 413 45, Gothenburg, Sweden; Corresponding author. Department of Medicine and Oncology, Southern Älvsborg Hospital, 50182, Borås, Sweden.
Helena Fohlin
Regional Cancer Center Southeast Sweden and Department of Biomedical and Clinical Medicine, Linköping University, Linköping, Sweden
Johan Rosell
Regional Cancer Center Southeast Sweden and Department of Biomedical and Clinical Medicine, Linköping University, Linköping, Sweden
Nils-Olof Bengtsson
Department of Oncology, Umeå University Hospital, Umeå, Sweden
Tommy Fornander
Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden
Thomas Hatschek
Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden
Henrik Lindman
Department of Oncology, Uppsala University Hospital, Uppsala, Sweden
Per Malmström
Department of Clinical Sciences Lund, Division of Oncology, Lund University, Lund, Sweden; Department of Haematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
Lisa Rydén
Department of Clinical Sciences Lund, Division of Surgery, Lund University, Lund, Sweden
Arne Wallgren
Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy, Sahlgrenska University Hospital, 413 45, Gothenburg, Sweden
Olle Stål
Department of Biomedical and Clinical Medicine and Department of Oncology, Linköping University, Linköping, Sweden
Bo Nordenskjöld
Department of Biomedical and Clinical Medicine and Department of Oncology, Linköping University, Linköping, Sweden
Background: Tamoxifen is an established treatment for breast cancer, but its long-term effects on survival and on secondary cancers are not fully evaluated. Material and methods: We studied 30 years outcome of 4124 postmenopausal patients who were randomized to receive (totally) two or five years of adjuvant tamoxifen. Results: After 5 years of follow-up, when tamoxifen treatment was finished in both groups, until 15 years of follow-up, overall mortality (HR 0.80, 95% CI 0.72–0.90, p < 0.001), breast cancer mortality for all patients (HR 0.80, 95% CI 0.68–0.94, p = 0.006) and breast cancer mortality for patients with estrogen receptor positive disease (HR 0.67, 95% CI 0.55–0.83, p < 0.001) were significantly reduced in the five-year group as compared to the two-year group. After 15 years, the difference remained but did not further increase.In the five-year group, the incidence of contralateral breast cancer was gradually reduced during the entire period of observation. The incidence of lung cancer was also reduced in the five-year group. In contrast there was an increased endometrial cancer incidence in the five-year group and for those receiving 40 mg of tamoxifen this incidence was further increased. Conclusion: Three more years of tamoxifen therapy reduced the risk of breast cancer mortality. The difference was established during the first 15 years after randomization. Moreover, the incidence of contralateral breast cancer gradually decreased for 30 years. The incidence of lung cancer was reduced in the five-year group. In contrast the incidence of endometrial cancer was increased.
