Predicting Prognosis and Tamoxifen Response in Breast Cancer. With a special focus on contralateral breast cancer.

One of the great challenges in breast cancer treatment today is to customize adjuvant treatment to each patient’s individual needs. To do this it is necessary to learn more about the prognostic and treatment predictive factors that determine the risk of relapse and response to a certain mode of treatment. This thesis describes studies on the effect of amplified in breast cancer 1 (AIB1), a coactivator of the oestrogen receptor, on prognosis and tamoxifen response through a controlled trial on premenopausal patients randomized to tamoxifen or a control group. AIB1 was found to be a negative prognostic factor, although patients with high AIB1 responded very well to tamoxifen. The findings were validated in two independent cohorts, one consisting of premenopausal patients not receiving tamoxifen, and the other of pre- and postmenopausal patients receiving tamoxifen. It has recently been suggested that the effect of AIB1 is modified by paired box 2 gene product (PAX2). PAX2 is a transcription factor important during embryogenesis, and may also play a role in carcinogenesis. This is the first time PAX2 has been investigated in well-defined cohorts of patients receiving or not receiving tamoxifen. PAX2 was not found to affect prognosis on its own, or to modify the effect of AIB1. The second part of this thesis focuses on contralateral breast cancer (CBC). Within their lifetime, previous breast cancer patients have a 2-20% risk of developing a second tumour in the contralateral breast. From the trial on premenopausal patients randomized to tamoxifen or control, it was found that without tamoxifen 12% developed CBC within a median follow-up period of 14 years. This risk was even higher in the youngest women (700) of patients with CBC in the Southern Healthcare Region of Sweden. From these data it was found that a short time interval between tumours was associated with a poorer prognosis, especially in young patients. This could indicate that some of these CBCs are in fact metastases of the first tumour, and would thus require different treatment. It could also be that tumours that develop soon after previous treatment have developed resistance to treatment and are of a more aggressive phenotype. Finally, it was found that patients who first noticed symptoms of their CBC themselves had a higher risk of developing metastases than patients diagnosed by mammography or clinical examination in a follow-up programme. The difference in prognosis in relation to mode of detection remained even when the time interval between tumours was ≥10 years, indicating that a long follow-up period is valuable

Prognosis, stage and oestrogen receptor status of contralateral breast cancer in relation to characteristics of the first tumour, prior endocrine treatment and radiotherapy.

A contralateral breast cancer (CBC) is today treated as an independent primary tumour, although recent data suggest risk and prognosis of CBC to be influenced by characteristics of and treatment given for the first tumour (BC1). We hereby investigate phenotypical and prognostic features of the second tumour (BC2) in relation to prior endocrine treatment and radiotherapy

Patient-reported outcomes one year after positive sentinel lymph node biopsy with or without axillary lymph node dissection in the randomized SENOMAC trial

Introduction: This report evaluates whether health related quality of life (HRQoL) and patient-reported arm morbidity one year after axillary surgery are affected by the omission of axillary lymph node dissection (ALND). Methods: The ongoing international non-inferiority SENOMAC trial randomizes clinically node-negative breast cancer patients (T1-T3) with 1-2 sentinel lymph node (SLN) macrometastases to completion ALND or no further axillary surgery. For this analysis, the first 1181 patients enrolled in Sweden and Denmark between March 2015, and June 2019, were eligible. Data extraction from the trial database was on November 2020. This report covers the secondary outcomes of the SENOMAC trial: HRQoL and patient-reported arm morbidity. The EORTC QLQC30, EORTC QLQ-BR23 and Lymph-ICF questionnaires were completed in the early postoperative phase and at one-year follow-up. Adjusted one-year mean scores and mean differences between the groups are presented corrected for multiple testing.Peer reviewe

Tamoxifen reduces the risk of contralateral breast cancer in premenopausal women: Results from a controlled randomised trial.

BACKGROUND: Adjuvant treatment with tamoxifen reduces the risk of contralateral breast cancer in hormone-responsive postmenopausal patients, whereas the effect in premenopausal women has not been fully elucidated. We have therefore studied the effect of tamoxifen on contralateral breast cancer in premenopausal women in a controlled randomised trial. PATIENTS AND METHODS: Premenopausal women (564) with stage II breast cancers were randomised to 2 years of tamoxifen versus control irrespective of oestrogen receptor (ER) and progesterone receptor (PgR) status. The median follow-up for patients not developing a contralateral cancer was 14 years. RESULTS: In the control group 35 women, and in the tamoxifen group 17 women, developed a contralateral breast cancer as a primary event. Tamoxifen significantly reduced the risk of contralateral breast cancer in all women regardless of age (hazard ratio (HR) 0.5, p=0.02). In subgroup analysis the risk reduction was most pronounced in patients /=50 years of age, although in these subgroups this did not reach statistical significance. The reduced risk of contralateral breast cancer was persistent during the whole follow-up time. CONCLUSION: In this randomised trial, adjuvant treatment using tamoxifen for 2 years reduced the incidence of contralateral breast cancer by 50% in all premenopausal women, and by 90% in women <40 years of age. The effect of tamoxifen was not significantly dependent on time