Neo-train: study protocol and feasibility results for a two-arm randomized controlled trial investigating the effect of supervised exercise during neoadjuvant chemotherapy on tumour response in patients with breast cancer.

BACKGROUND: Prehabilitation with exercise interventions during neoadjuvant chemotherapy (NACT) is effective in reducing physical and psychosocial chemotherapy-related adverse events in patients with cancer. In preclinical studies, data also support a growth inhibitory effect of aerobic exercise on the tumour microenvironment with possible improved chemotherapy delivery but evidence in human patients is limited. The aim of the study here described is to investigate if supervised exercise with high-intensity aerobic and resistance training during NACT can improve tumour reduction in patients with breast cancer. METHODS: This parallel two-armed randomized controlled trial is planned to include 120 women aged ≥ 18 years with newly diagnosed breast cancer starting standard NACT at a university hospital in Denmark (a total of 90 participants needed according to the power calculation and allowing 25% (n = 30) dropout). The participants will be randomized to usual care or supervised exercise consisting of high-intensity interval training on a stationary exercise bike and machine-based progressive resistance training offered three times a week for 24 weeks during NACT, and screening-based advice to seek counselling in case of moderate-severe psychological distress (Neo-Train program). The primary outcome is tumour size change (maximum diameter of the largest lesion in millimetre) measured by magnetic resonance imaging prior to surgery. Secondary outcomes include clinical/pathological, physical and patient-reported measures such as relative dose intensity of NACT, hospital admissions, body composition, physical fitness, muscle strength, health-related quality of life, general anxiety, depression, and biological measures such as intratumoural vascularity, tumour infiltrating lymphocytes, circulating tumour DNA and blood chemistry. Outcomes will be measured at baseline (one week before to 1-2 weeks after starting NACT), during NACT (approximately week 7, 13 and 19), pre-surgery (approximately week 21-29), at surgery (approximately week 21-30) and 3 months post-surgery (approximately 33-42 weeks from baseline). DISCUSSION: This study will provide novel and important data on the potential benefits of supervised aerobic and resistance exercise concomitant to NACT on tumour response and the tumour microenvironment in patients with breast cancer, with potential importance for survival and risk of recurrence. If effective, our study may help increase focus of exercise as an active part of the neoadjuvant treatment strategy. TRIAL REGISTRATION: The trial was registered at ClinicalTrials.gov (NCT04623554) on November 10, 2020.

The long-term burden of a symptom cluster and association with longitudinal physical and emotional functioning in breast cancer survivors.

BACKGROUND: Fatigue, insomnia and pain are some of the most common and distressing symptoms experienced during breast cancer (BC) treatment and survivorship. The symptoms have been found to impact one another and to form a symptom cluster, and greater severity of the symptoms may be negatively associated with physical and emotional functioning in survivorship. In exploratory analyses from a randomized controlled trial examining the effect of progressive resistance training on the development of lymphedema after BC, we aimed to examine the burden of the symptom cluster fatigue-pain-insomnia, and its prognostic value for long-term symptom severity as well as emotional and physical functioning. MATERIAL AND METHODS: Latent profile analysis was used to identify groups with similar severity of pain, fatigue and insomnia among 158 patients with BC two weeks after surgery. Mixed effects Tobit regression models were used to estimate fatigue, pain, insomnia, and physical and emotional functioning 20 weeks, 1 year and 3.5 years after surgery. RESULTS: Two symptom burden groups were identified: 80% of women had a low severity while 20% of women had a high severity of the three symptoms after BC surgery. 3.5 years later, the women with high symptom burden post-surgery still had higher pain, insomnia and fatigue scores than women with low symptom burden. High symptom burden post-surgery was associated with worse physical functioning 3.5 years later, while emotional functioning was only negatively impacted during the first year. DISCUSSION: These findings warrant larger studies investigating if symptom burden early in BC trajectory can be used for risk stratification for persistent symptoms and diminished physical functioning with the purpose of developing and implementing targeted interventions.

Effects of an early intervention with Hyperbaric Oxygen Treatment on arm lymphedema and quality of life after breast cancer-an explorative clinical trial.

PURPOSE: Lymphedema (LE) is a common complication after breast cancer treatment, which negatively affects the quality of life (QOL). Hyperbaric Oxygen Treatment (HBOT) is an established treatment for radiation-induced tissue injury, but evidence of effect on breast cancer-related LE is inconclusive. We aimed to explore effects of HBOT on early breast cancer-related LE and the implications for QOL. METHODS: We invited women with breast cancer treated with surgery, axillary dissection and radiotherapy, who had participated in a randomized controlled trial and who presented with LE 1 year after surgery. In a prospective observational study design, change in LE was assessed with perometry, dual-energy X-ray absorptiometry (DXA) and lymphoscintigraphy, and QOL by validated self-report scales. Participants were offered 40 sessions of HBOT on every weekday for 8 weeks and were followed for 6 months. RESULTS: Out of 50 eligible participants, 20 women accepted participation. Nineteen women initiated and completed treatment and follow-up. None of the objective measures of LE severity showed consistent changes during the study period, but participants reported significant improvements in QOL (physical functioning, fatigue, insomnia and breast and arm symptoms), with improvements peaking at 6-month follow-up. CONCLUSION: Participants receiving HBOT experienced improved QOL without consistently significant changes in arm mass, volume or lymphatic drainage. These results call for studies into differential effect in patient sub-groups, and a large-scale, randomized placebo-controlled trial with long-term follow-up to assess the effect of HBOT in patients with soft tissue radiation injuries after breast cancer seems warranted. TRIAL REGISTRATION: Danish Health and Medicines Authority, EUDRACT no. 2015-000,604-25 Ethical committee of the Capitol Region, No. R96-A6604-14-S22.

Use of hypnotics among women diagnosed with cervical cancer - A population-based cohort study.

OBJECTIVE: Previous studies suggest that sleeping problems are frequent after cervical cancer. However, the evidence on the use of hypnotics is sparse. We investigated if women diagnosed with cervical cancer have an increased risk of using hypnotics and identified risk factors for prolonged use. METHODS: In this nationwide register-based cohort study, 4264 women diagnosed with cervical cancer from 1997 to 2013 and 36,632 cancer-free women were followed in registers until 2016. Prolonged use of hypnotics was defined as more than three prescriptions with no more than three months in between. Data were analysed using Cox proportional hazards regression models and multistate Markov models separately for women with localized and advanced cervical cancer. RESULTS: The rate of first use of hypnotics was substantially increased during the first year after cervical cancer diagnosis compared to cancer-free women (HRlocalized 4.4, 95% CI 3.9-5.1; HRadvanced 8.9, 95% CI 7.5-10.6) and remained markedly increased for up to five years after diagnosis. Dependent on stage of disease and age, 1.4 to 4.7 excess women per 100 with cervical cancer were prolonged users of hypnotics compared to cancer-free women one year after diagnosis. Risk factors for prolonged use of hypnotics were higher age, short education, previous use of antidepressants or anxiolytics, and advanced disease. CONCLUSIONS: Women diagnosed with cervical cancer are at increased risk of prolonged use of hypnotics. For the majority, treatment with hypnotics is initiated within the first year after cancer diagnosis, but the rate of first use is increased for up to five years.

Socioeconomic inequality in cancer in the Nordic countries. A systematic review.

BACKGROUND: Despite structural and cultural similarities across the Nordic countries, differences in cancer survival remain. With a focus on similarities and differences between the Nordic countries, we investigated the association between socioeconomic position (SEP) and stage at diagnosis, anticancer treatment and cancer survival to describe patterns, explore underlying mechanisms and identify knowledge gaps in the Nordic countries. METHODS: We conducted a systematic review of population based observational studies. A systematic search in PubMed, EMBASE and Medline up till May 2021 was performed, and titles, abstracts and full texts were screened for eligibility by two investigators independently. We extracted estimates of the association between SEP defined as education or income and cancer stage at diagnosis, received anticancer treatment or survival for adult patients with cancer in the Nordic countries. Further, we extracted information on study characteristics, confounding variables, cancer type and results in the available measurements with corresponding confidence intervals (CI) and/or p-values. Results were synthesized in forest plots. RESULTS: From the systematic literature search, we retrieved 3629 studies, which were screened for eligibility, and could include 98 studies for data extraction. Results showed a clear pattern across the Nordic countries of socioeconomic inequality in terms of advanced stage at diagnosis, less favorable treatment and lower cause-specific and overall survival among people with lower SEP, regardless of whether SEP was measured as education or income. CONCLUSION: Despite gaps in the literature, the consistency in results across cancer types, countries and cancer outcomes shows a clear pattern of systematic socioeconomic inequality in cancer stage, treatment and survival in the Nordic countries. Stage and anticancer treatment explain some, but not all of the observed inequality in overall and cause-specific survival. The need for further studies describing this association may therefore be limited, warranting next step research into interventions to reduce inequality in cancer outcomes. STUDY REGISTRATION: Prospero protocol no: CRD42020166296.

Effect of progressive resistance training on persistent pain after axillary dissection in breast cancer: a randomized controlled trial.

PURPOSE: Persistent pain is a known challenge among breast cancer survivors. In secondary analyses of a randomized controlled trial, we examined the effect of progressive resistance training on persistent pain in the post-operative year in women treated for breast cancer with axillary lymph node dissection. METHODS: We randomized 158 women after BC surgery with Axillary Lymph Node Dissection (ALND) (1:1) to usual care or a 1-year, supervised and self-administered, progressive resistance training intervention initiated 3 weeks after surgery. A questionnaire at baseline, 20 weeks and 12 months assessed the intensity and frequency of pain, neuropathic pain and influence of pain on aspects of daily life. We analysed the effect using linear mixed models and multinomial logistic regression models for repeated measures. RESULTS: A high percentage of participants experienced baseline pain (85% and 83% in the control and intervention groups respectively) and by the 12 month assessment these numbers were more than halved. A high proportion of participants also experienced neuropathic pain (88% and 89% in control and intervention group respectively), a finding that was stable throughout the study period. The effect on intensity of pain indicators favoured the exercise group, although most estimates did not reach statistical significance, with differences being small. CONCLUSION: For women who had BC surgery with ALND, our progressive resistance training intervention conferred no benefit over usual care in reducing pain. Importantly, it did not increase the risk of pain both in the short and long term rehabilitative phase.

Progressive resistance training to prevent arm lymphedema in the first year after breast cancer surgery: Results of a randomized controlled trial.

BACKGROUND: Existing research suggests that progressive resistance training (PRT) after breast cancer (BC) surgery is safe, but the preventive effect on arm lymphedema has yet to be determined. METHODS: Women aged 18 to 75 years who were undergoing BC surgery with axillary lymph node dissection were eligible for the study. Recruited on the day of surgery, participants were allocated to intervention or usual care by computer randomization. The intervention consisted of PRT 3 times per week: in the first 20 weeks as a supervised group exercise and in the last 30 weeks as a self-administered exercise. The primary outcome was arm lymphedema, which was defined as a >3% increase in the interlimb volume difference by water displacement. Measurements were made at the baseline and at a 12-month follow-up by physiotherapists blinded to group allocation. Analyses of effects included t tests and regression models; missing data were addressed by multiple imputation. RESULTS: Among the 158 randomized women, no mean group difference was found in arm volume (0.3%; 95% confidence interval, -1.7% to 2.3%) or lymphedema incidence (adjusted odds ratio, 1.2; 95% confidence interval, 0.5-2.8). None of the participants exited the program because of adverse events. CONCLUSIONS: This study provides no evidence that PRT can prevent arm lymphedema in the first year after BC, but the results corroborate the importance and safety of resistance training for patients, including women at high risk for lymphedema.

Increased risk for depression persists for years among women treated for gynecological cancers - a register-based cohort study with up to 19 years of follow-up.

OBJECTIVE: Little is known about long-term risk of depression in women treated for gynecological cancers. We aim to investigate risk for depression among these women compared to women without a history of cancer. METHODS: We followed 16,833 women diagnosed with gynecological cancers between 1998 and 2013 and 138,888 reference women in nationwide registers for up to 19 years. Women with a history of severe psychiatric disorders, and those who had redeemed a prescription for antidepressants three years before study entry were excluded from analyses. Regression analyses were applied to compare the risk for antidepressant use among patients compared to reference women, and to investigate associations between socio-demographic as well as clinical risk factors and use of antidepressants. RESULTS: We found an increased risk for antidepressant use among women treated for ovarian (HR 4.14, 95% CI 3.74-4.59), endometrial (HR 2.19, 95% CI 1.97-2.45), and cervical cancer (HR 3.14, 95% CI 2.74-3.61) one year after diagnosis. This increased risk persisted years after diagnosis in all three groups, with the longest (up to eight years) found for ovarian cancer. Advanced disease was strongly associated with antidepressant use followed by short education, and comorbidity. CONCLUSIONS: Women diagnosed with gynecological cancer have an increased risk for depression compared to reference women. The risk remains increased for years after diagnosis throughout and beyond standard oncological follow-up care. Advanced disease, short education, and comorbidity are factors associated with antidepressant use in this patient group.

Adherence to a long-term progressive resistance training program, combining supervised and home-based exercise for breast cancer patients during adjuvant treatment.

Background: The purpose of the study was to examine adherence and identify patient- and treatment-related factors associated with adherence to a 20-week combined supervised and home-based progressive resistance training program in women treated for breast cancer. Methodology: The study population consisted of the intervention group in a randomized clinical trial examining the effect of resistance exercise on lymphoedema prevention (n = 82). The full program lasted 50 weeks, with an initial 20 weeks combined supervised and home-based exercise followed by 30 weeks self-administered exercise. Information about attendance rates (supervised exercise) and exercise dairies (home-based exercise) in the first 20 weeks was available for 74 and 62 participants, respectively. Adherence was measured as numbers of exercise sessions performed divided by expected number of exercise sessions with >2/3 categorized as high adherence. Age-adjusted odds ratios (OR) were used to assess the associations between patient- and treatment-related factors with adherence. Results: The number of participants with high adherence to supervised exercise decreased in the late period (from week 11 onward) compared to the early period (65% vs. 48%) whereas the proportion of participants with high adherence to home-based exercise remained close to 55%. The most prominent factor associated with high adherence to supervised exercise was neoadjuvant chemotherapy [OR 7.09; 95% confidence interval (CI), 1.12-44.62]. For home-based exercise, lower adherence was seen in obese participants (OR 0.16; 95% CI, 0.04-0.65) and in participants with average or below average lower body muscle strength at baseline (OR 0.12; 95% CI, 0.03-0.46). Conclusion: The results of this study offer valuable information on factors associated with adherence to a program of supervised and home-based exercise. Interventions may be adapted to ensure higher adherence rates through supportive efforts targeted to women who are obese, have low muscle strength and who receive no or adjuvant chemotherapy (as opposed to neoadjuvant chemotherapy) during exercise.

Effect of progressive resistance training on health-related quality of life in the first year after breast cancer surgery - results from a randomized controlled trial.

Aims: To examine the effect of progressive resistance training (PRT) on health related quality of life and a predefined symptom cluster of pain-sleep-fatigue. Methods: This study was a planned secondary analysis of a randomized controlled trial examining the effect of PRT on prevention of arm lymphedema in a population of women between 18 and 75 years undergoing breast cancer surgery with axillary lymph node dissection. Participants were allocated by computer randomization to usual care control or a PRT intervention in a 1:1 ratio. The intervention, initiated in the third post-operative week, consisted of three times PRT per week, supervised in groups in the first 20 weeks, and self-administered in the following 30 weeks. Questionnaire assessments were made at baseline, 20 weeks and 12 months, with the European Organization for Research and Treatment in Cancer Core questionnaire (EORTC QLQ C30) and the Functional Assessment of Chronic Illness Therapy-(FACIT) fatigue questionnaire. The symptom cluster of pain-sleep-fatigue was measured with a constructed score adding EORTC C30 subscales of insomnia, pain, and fatigue. Data were treated as repeated measurements and analyzed with mixed models. Results: Among 158 recruited participants, we found a clinically relevant increased emotional functioning with nine points at both follow-ups (p = .02), and 16 and 11 points at 20 weeks and 12 months respectively (p = .04) in social functioning. Furthermore, in the subgroup of women with the symptom cluster pain-sleep-fatigue present at baseline, a significant effect was found for global health status (p = .01) and social functioning (p = .02). Conclusion: To our knowledge, this is the first study to report clinically relevant effects of PRT on social and emotional functioning in the first postoperative year after breast cancer surgery. Furthermore, a subgroup of women with the pain-sleep-fatigue symptom cluster had particular benefit from PRT on global health status and social functioning.

Progressive strength training to prevent LYmphoedema in the first year after breast CAncer - the LYCA feasibility study.

BACKGROUND: Lymphoedema is a common late effect after breast cancer (BC) that has no effective cure once chronic. Accumulating evidence supports progressive strength training (PRT) as a safe exercise modality in relation to the onset and exacerbation of lymphoedema. In the 'preventive intervention against LYmphoedema after breast CAncer' (LYCA) feasibility study we examined the feasibility of a program of PRT in the first year after BC to inform a planned randomised controlled trial (RCT). MATERIAL AND METHODS: LYCA was a one-group prospective pilot trial inviting women operated with axillary lymph node dissection for unilateral primary BC. Participants exercised three times a week for 50 weeks (20 weeks supervised followed by 30 weeks home-based exercise). The program ensured slow individualised progression during the exercise program. The primary outcome was feasibility measured by eligibility and recruitment rates, as well as questionnaire-assessed satisfaction and adherence to exercise. Furthermore, we assessed arm interlimb volume difference by water displacement, muscle strength by dynamic and isometric muscle testing and range of movement in the shoulder by goniometry. RESULTS: In August 2015, eight of 11 eligible patients accepted participation. Two of them dropped out early due to other health issues. The remaining six participants had high exercise adherence through the supervised period, but only three maintained this through the home exercise period. Program satisfaction was high and no serious adverse events from testing or exercising were reported. One participant presented with lymphoedema at 50-week follow-up. Muscle strength markedly increased with supervised exercise, but was not fully maintained through the home exercise period. Range of shoulder movement was not negatively affected by the program. CONCLUSION: Recruitment, testing, and exercise in LYCA was safe and feasible. At the 50-week follow-up, there was one case of lymphoedema. The LYCA program will be further tested in a full-scale RCT.

Muscle mass and physical function in patients with bladder cancer-Data from a prematurely terminated prospective cohort study.

Background: Patients with bladder cancer (BC) have a high prevalence of comorbidity and low adherence to systemic anticancer treatment but it is unknown whether this is associated with sarcopenia. Objective: We aimed to investigate if the sarcopenia-defining parameters (muscle strength, muscle mass and physical performance) were associated with reduced adherence to systemic anticancer treatment in patients with BC, and if these muscle domains changed during treatment. Methods: Patients >18 years of age with BC referred for chemotherapy or immunotherapy at Department of Oncology, Rigshospitalet, Denmark were eligible for study inclusion. Measurements were performed before treatment initiation and within one week after treatment termination, and consisted of assessments of muscle strength, muscle mass, and physical performance. Data was compared with thresholds outlined by the European Working Group on Sarcopenia in Older Patient's (EWGSOP2) guidelines and a healthy, age-matched Danish cohort. Results: Over a period of 29 months, we included 14 patients of whom two completed follow-up measurements. The recruitment rate was <50% of planned due to logistics and Covid-19 related limitations. Consequently, a decision to prematurely terminate the study was made. No patients fulfilled EWGSOP2 criteria for sarcopenia, but the majority had reduction in one or more muscle domains compared to healthy, age-matched individuals. The majority of patients had poor treatment tolerance, leading to dose reductions and postponed treatments. Conclusions: In this prematurely terminated study, no patients fulfilled EWGSOP2 criteria for sarcopenia, yet, most patients were affected in one or more muscle domains and the majority had compromised treatment adherence.

Interrater Reliability of Dynamic Muscle Testing After Breast Cancer Surgery in Women at High Risk of Lymphedema: To Improve Quality in Clinical Practice.

Background: The purpose of this study is to determine the interrater reliability of dynamic muscle tests in the early rehabilitation phase in women after breast cancer surgery with axillary lymph node dissection (ALND) based on the "preventive intervention against lymphedema after breast cancer" (LYCA) randomised controlled trial. Methods: Fifteen women treated with breast cancer surgery including ALND were recruited from participants in the LYCA trial. In this interrater reliability study, women were tested in 4 dynamic muscle tests by 2 physiotherapists at a Capital Hospital in Denmark. Intraclass correlation coefficients (ICCs) with 95% confidence intervals (CIs) was used to assess the relative reliability between raters. A Bland-Altman plot and limits of agreement were calculated to describe the absolute reliability. Results: All 6 subtests displayed high interrater reliability. ICC values were: leg press 0.96 (95% CI = 0.87-0.99), elbow flexion (contralateral) 0.94 (0.83-0.98), elbow flexion (affected arm) 0.93 (0.80-0.98), elbow extension 0.80 (0.41-0.93), shoulder abduction (contralateral) 0.89 (0.68-0.96), and shoulder abduction (affected arm) 0.91 (0.74-0.97). Cumulated interrater reliability for the test battery was very high (ICC = 0.99, 95% CI = 0.990-1.0). The absolute reliability of this study was considered high, and the absence of large shifts between mean and the line of 0 difference suggest no systematic bias that could influence clinical interpretation. Conclusions: The dynamic muscle tests evaluated in this study had high interrater reliability and can be used reliably in women in the postoperative phase after breast cancer surgery with ALND.

Gynaecological cancer leads to long-term sick leave and permanently reduced working ability years after diagnosis.

PURPOSE: The aim of the study was to investigate overall patterns in labour market affiliation, risk for permanently reduced work ability and prevalence of long-term sickness absence among women diagnosed with gynaecological cancer. METHODS: We followed 8451 women diagnosed with ovarian, endometrial or cervical cancer, and 72,311 women with no history of cancer in nationwide registers for up to 19 years (mean 7.5 years). We computed hazards ratios for permanently reduced working ability and annual proportions of long-term sick leave. RESULTS: Patterns of labour market affiliation varied by cancer diagnosis and stage. The hazard of permanently reduced working ability was increased for survivors of all three cancers but most pronounced for women diagnosed with advanced ovarian cancer. The highest hazard ratios were found 2-5 years after diagnosis, and they persisted for years in all groups and throughout the follow-up period of 19 years in women diagnosed with advanced cervical cancer. In the subgroups of women who continued to be potentially active on the labour market, long-term sick leave was more prevalent among cancer survivors than women with no history of cancer up to 10 years after diagnosis. CONCLUSIONS: Women diagnosed with localised as well as advanced gynaecological cancer are at prolonged risk for permanently reduced working ability and long-term sick leave. IMPLICATIONS FOR CANCER SURVIVORS: Gynaecological cancer can have long-term as well as permanent consequences for working ability, and survivors who remain active on the labour market might have to take more sick leave even years after cancer diagnosis than other women at their age.

Residential exposure to traffic noise and leisure-time sports - A population-based study.

BACKGROUND: Traffic levels have been found a significant environmental predictor for physical inactivity. A recent study suggested that traffic noise annoyance was associated with lower physical activity. OBJECTIVES: We investigated associations between modelled residential traffic noise and leisure-time sports. METHODS: In the Diet, Cancer and Health cohort, we performed cross-sectional analyses using data from the baseline questionnaire (1993-97), and longitudinal analyses of change between baseline and follow-up (2000-02). People reported participation (yes/no) and hours of leisure-time sport, from which we calculated MET hrs/week. Present and historical addresses from 1987 to 2002 were found in national registries, and traffic noise was modelled 1 and 5 years before enrolment, and from baseline to follow-up. Analyses were performed using logistic and linear regression. RESULTS: Traffic noise exposure 5 years before baseline was associated with higher prevalence odds ratio of non-participation in leisure-time sports; significantly for road traffic noise (odds ratio (OR): 1.10; 95% confidence interval (CI): 1.07-1.13) and borderline for railway noise (OR: 1.03; 95% CI: 0.99-1.07), per 10dB. In longitudinal analyses, a 10dB higher road traffic noise was associated with a higher prevalence odds ratio of ceasing (OR: 1.12; 95% CI: 1.07-1.18) and a lower prevalence odds ratio of initiating (OR: 0.92; 95% CI: 0.87-0.96) leisure-time sports. Exposure to railway noise was negatively associated with baseline MET hrs/week, whereas no association was found in longitudinal analyses, or for road traffic noise. CONCLUSION: The study suggests that long-term exposure to residential road traffic noise is negatively associated with leisure-time sports. Results for railway noise were less consistent.

Physical activity and survival in breast cancer.

PURPOSE: Knowledge about lifestyle factors possibly influencing survival after breast cancer (BC) is paramount. We examined associations between two types of postdiagnosis physical activity (PA) and overall survival after BC. PATIENTS AND METHODS: We used prospective data on 959 BC survivors from the Diet, Cancer, and Health cohort, all enrolled before diagnosis. Self-reported PA was measured as time per activity, and estimated metabolic equivalent task (MET)-hours per week were summed for each activity. We constructed measures for household, exercise, and total PA. The association between postdiagnosis PA and all-cause mortality was estimated as hazard ratio (HRs) based on Cox proportional hazards model, with time since diagnosis as the underlying time scale. Prediagnosis PA, body mass index (BMI), and receptor status were examined as potential effect modifiers. RESULTS: We identified 144 deaths from all causes during the study period. In adjusted analyses, exercise PA above eight MET h/week compared to lower levels of activity was significantly associated with improved overall survival (HR, 0.68; confidence interval [CI]: 0.47-0.99). When comparing participation in exercise to non-participation, we found a 44% risk reduction in overall survival (HR, 0.56; CI: 0.33-0.95). Neither between household nor total PA and overall survival did, we find significant associations. Prediagnosis PA, BMI, and receptor status did not modify the effect significantly. CONCLUSION: Exercise PA corresponding to 2.5 h or more of brisk weekly walking after BC diagnosis may reduce mortality by up to 32% compared to low-level exercise. Participation in exercise PA may reduce mortality by 44% compared to non-participation.