Forty years of landmark trials undertaken by the Danish Breast Cancer Cooperative Group (DBCG) nationwide or in international collaboration

Capecitabine monotherapy as first-line treatment in advanced HER2-normal breast cancer - a nationwide, retrospective study

Background and purpose: Capecitabine can be used as first-line treatment for advanced breast cancer. However, real-world data on efficacy of capecitabine in this setting is sparse. The purpose of the study is to evaluate outcomes of patients with Human Epidermal Growth Factor Receptor (HER2)-normal advanced breast cancer treated with capecitabine monotherapy as first-line treatment.

MATERIAL AND METHODS

The study utilized the Danish Breast Cancer Group (DBCG) database and was conducted retrospectively across all Danish oncology departments. Inclusion criteria were female patients, with HER2-normal advanced breast cancer treated with capecitabine monotherapy as the first-line treatment from 2010 to 2020. The primary endpoints were overall survival (OS) and progression-free survival (PFS).

RESULTS

A total of 494 patients were included. Median OS was 16.4 months (95% confidence interval [CI]: 14.5-18.0), and median PFS was 6.0 months (95% CI: 5.3-6.7). Patients with estrogen receptor (ER)-positive disease had significantly longer OS (median: 22.8 vs. 10.5 months, p < 0.001) and PFS (median: 7.4 vs. 4.9 months, p = 0.003), when compared to ER-negative patients. Stratifying by age, patients under 45 years displayed a median PFS of 4.1 months, while those aged 45-70 years and over 70 years had median PFS of 5.7 and 7.2 months, respectively (p = 0.01).

INTERPRETATION

 In this nationwide study, the efficacy of capecitabine as a first-line treatment for HER2-normal advanced breast cancer is consistent with other, mainly retrospective, studies. However, when assessed against contemporary and newer treatments, its effectiveness appears inferior to alternative chemotherapies or targeted therapies.

Have the recent advancements in cancer therapy and survival benefitted patients of all age groups across the Nordic countries? NORDCAN survival analyses 2002-2021

BACKGROUND

Since the early 2000s, overall and site-specific cancer survival have improved substantially in the Nordic countries. We evaluated whether the improvements have been similar across countries, major cancer types, and age groups.

MATERIAL AND METHODS

Using population-based data from the five Nordic cancer registries recorded in the NORDCAN database, we included a cohort of 1,525,854 men and 1,378,470 women diagnosed with cancer (except non-melanoma skin cancer) during 2002-2021, and followed for death until 2021. We estimated 5-year relative survival (RS) in 5-year calendar periods, and percentage points (pp) differences in 5-year RS from 2002-2006 until 2017-2021. Separate analyses were performed for eight cancer sites (i.e. colorectum, pancreas, lung, breast, cervix uteri, kidney, prostate, and melanoma of skin).

RESULTS

Five-year RS improved across nearly all cancer sites in all countries (except Iceland), with absolute differences across age groups ranging from 1 to 21 pp (all cancer sites), 2 to 20 pp (colorectum), -1 to 36 pp (pancreas), 2 to 28 pp (lung), 0 to 9 pp (breast), -11 to 26 pp (cervix uteri), 2 to 44 pp (kidney), -2 to 23 pp (prostate) and -3 to 30 pp (skin melanoma). The oldest patients (80-89 years) exhibited lower survival across all countries and sites, although with varying improvements over time.

INTERPRETATION

Nordic cancer patients have generally experienced substantial improvements in cancer survival during the last two decades, including major cancer sites and age groups. Although survival has improved over time, older patients remain at a lower cancer survival compared to younger patients.

Shared decision making with breast cancer patients - does it work? Results of the cluster-randomized, multicenter DBCG RT SDM trial

BACKGROUND AND PURPOSE

Shared decision making (SDM) is a patient engaging process advocated especially for preference-sensitive decisions, such as adjuvant treatment after breast cancer. An increasing call for patient engagement in decision making highlights the need for a systematic SDM approach. The objective of this trial was to investigate whether the Decision Helper (DH), an in-consultation patient decision aid, increases patient engagement in decisions regarding adjuvant whole breast irradiation.

MATERIAL AND METHODS

Oncologists at four radiotherapy units were randomized to practice SDM using the DH versus usual practice. Patient candidates for adjuvant whole breast irradiation after breast conserving surgery for node-negative breast cancer were eligible. The primary endpoint was patient-reported engagement in the decision process assessed with the Shared Decision Making Questionnaire (SDM-Q-9) (range 0-100, 4 points difference considered clinical relevant). Other endpoints included oncologist-reported patient engagement, decisional conflict, fear of cancer recurrence, and decision regret after 6 months.

RESULTS

Of the 674 included patients, 635 (94.2%) completed the SDM-Q-9. Patients in the intervention group reported higher level of engagement (median 80; IQR 68.9 to 94.4) than the control group (71.1; IQR 55.6 to 82.2; p < 0.0001). Oncologist-reported patient engagement was higher in the invention group (93.3; IQR 82.2 to 100) compared to control group (73.3; IQR 60.0 to 84.4) (p < 0.0001).

CONCLUSION

Patient engagement in medical decision making was significantly improved with the use of an in-consultation patient decision aid compared to standard. The DH on adjuvant whole breast irradiation is now recommended as standard of care in the Danish guideline.

Age-specific survival trends and life-years lost in women with breast cancer 1990-2016: the NORDCAN survival studies

BACKGROUND

A recent overview of cancer survival trends 1990-2016 in the Nordic countries reported continued improvements in age-standardized breast cancer survival among women. The aim was to estimate age-specific survival trends over calendar time, including life-years lost, to evaluate if improvements have benefited patients across all ages in the Nordic countries.

METHODS

Data on breast cancers diagnosed 1990-2016 in Denmark, Finland, Iceland, Norway, and Sweden were obtained from the NORDCAN database. Age-standardized and age-specific relative survival (RS) was estimated using flexible parametric models, as was reference-adjusted crude probabilities of death and life-years lost.

RESULTS

Age-standardized period estimates of 5-year RS in women diagnosed with breast cancer ranged from 87% to 90% and 10-year RS from 74% to 85%. Ten-year RS increased with 15-18 percentage points from 1990 to 2016, except in Sweden (+9 percentage points) which had the highest survival in 1990. The largest improvements were observed in Denmark, where a previous survival disadvantage diminished. Most recent 5-year crude probabilities of cancer death ranged from 9% (Finland, Sweden) to 12% (Denmark, Iceland), and life-years lost from 3.3 years (Finland) to 4.6 years (Denmark). Although survival improvements were consistent across different ages, women aged ≥70 years had the lowest RS in all countries. Period estimates of 5-year RS were 94-95% in age 55 years and 84-89% in age 75 years, while 10-year RS were 88-91% in age 55 years and 69-84% in age 75 years. Women aged 40 years lost on average 11.0-13.8 years, while women lost 3.8-6.0 years if aged 55 and 1.9-3.5 years if aged 75 years.

CONCLUSIONS

Survival for Nordic women with breast cancer improved from 1990 to 2016 in all age groups, albeit with larger country variation among older women where survival was also lower. Women over 70 years of age have not had the same survival improvement as women of younger age.

Aquaporin-5 in breast cancer

The water channel aquaporin‐5 (AQP5) is essential in transepithelial water transport in secretory glands. AQP5 is ectopically overexpressed in breast cancer, where expression is associated with lymph node metastasis and poor prognosis. Besides the role in water transport, AQP5 has been found to play a role in cancer metastasis, migration, and proliferation. AQP5 has also been shown to be involved in the dysregulation of epithelial cell–cell adhesion; frequently observed in cancers. Insight into the underlying molecular mechanisms of how AQP5 contributes to cancer development and progression is essential for potentially implementing AQP5 as a prognostic biomarker and to develop targeted intervention strategies for the treatment of breast cancer patients.

Risk of coronary artery disease after adjuvant radiotherapy in 29,662 early breast cancer patients: A population-based Danish Breast Cancer Group study

PURPOSE

Radiotherapy (RT) for early breast cancer (BC) reduces the risk of recurrence and improves overall survival. However, thoracic RT may cause some incidental RT dose to the heart with subsequent risk of heart disease. During 2000-2010, CT-based RT planning was gradually introduced. The aim of this study was to investigate the risk of cardiac events in left-sided compared with right-sided BC patients treated during a non-CT-based (1999-2007) vs a CT-based period (2008-2016).

MATERIAL AND METHODS

Information on BC and cardiac events among Danish women was obtained from population-based medical registers. Patients diagnosed with BC during 1999-2016, were included. A cardiac event was defined as coronary artery disease or severe valvular heart disease.

RESULTS

Among 29,662 patients, 22,056 received RT. For those irradiated during the non-CT-based period, the 10-year cumulative risk of cardiac event was 1.7% (95% CI 1.4-2.0) at median follow-up of 11.1 years. The incidence rate ratio (IRR) for cardiac event in left-sided vs right-sided patients was 1.44 (1.07-1.94) and a trend towards worse outcome was seen within the first 10 years after RT and approached statistical significance with longer follow-up. Among patients irradiated during the CT-based period, the 10-year cumulative risk of cardiac event was 2.1% (1.8-2.4) at median 6.8 years follow-up. The IRR for cardiac event in left-sided vs right-sided patients was 0.90 (0.69-1.16) and no trend towards worse outcome within the first 10 years was observed.

CONCLUSION

This study confirmed a higher risk of cardiac events in left-sided vs right-sided BC patients irradiated during a non-CT-based period. For patients irradiated during a CT-based period, no increased risk of cardiac events in left-sided vs right-sided patients was observed within the first 10 years after RT, whilst information on cardiac events beyond 10 years after RT was limited.

Trajectory of recurrent falls in post-menopausal breast cancer survivors and in matched cancer-free controls

PURPOSE

Cross-sectional studies suggest that falls are prevalent among older breast cancer survivors. However, fall risk in this population has not been comprehensively examined. Therefore, we compared fall risk in older women post-breast cancer diagnosis to fall risk before cancer diagnosis and to risk in cancer-free matched controls.

METHODS

Among 2019 women in the Women's Health Initiative with localized breast cancer diagnosed at age ≥ 60 years with fall assessment data for 3 years pre-diagnosis and 3 years post-diagnosis, recurrent fall risk post-diagnosis was compared to risk in 2019 cancer-free controls matched by age, year of WHI entry, and baseline fall frequency. Generalized estimating equations under a logistic regression model were used to compare fall recurrence in breast cancer survivors and controls. Multi-variable models were adjusted for the matching factors, race/ethnicity, body mass index, and multiple chronic conditions.

RESULTS

In breast cancer survivors aged 70.8 years (mean) at diagnosis, over the 3-year pre-diagnosis interval, recurrent falls were reported by 18.5%. Over the 3-year post-diagnosis interval, recurrent falls were reported by 21.8% of breast cancer survivors and 20.0% of controls over the same time period (P = 0.27). Recurrent fall risk did not differ between breast cancer survivors and control women (OR 1.07, 95% CI 0.92-1.25), even after multi-variable adjustment.

CONCLUSIONS

In contrast to prior reports, older breast cancer survivors were not more likely to experience recurrent falls than age-matched counterparts. These findings underscore the need for incorporation of cancer-free control populations in survivorship studies to distinguish cancer sequelae from processes related to aging.

25-Hydroxyvitamin D at time of breast cancer diagnosis and breast cancer survival

PURPOSE

Previous studies have shown that low levels of 25-hydroxyvitamin D (25(OH)D) are associated with a poorer breast cancer survival. The relationship between vitamin D status and breast cancer outcomes is however still debated. The aim of the present study was to investigate the association between 25(OH)D blood levels measured at time of diagnosis and event-free survival (EFS) and overall survival (OS) in a large cohort of patients with early-stage primary invasive breast cancer.

METHODS

From April 2008 to April 2013, 25(OH)D status was measured at time of diagnosis in all women operated for early stage primary invasive breast cancer at Rigshospitalet, Copenhagen, Denmark. Associations between 25(OH)D and EFS and OS were investigated using a Cox Proportional hazards model, adjusting for age, disease characteristics, time period, and BMI. Differences in survival were evaluated by hazard ratios (HR).

RESULTS

In the present study, 2510 women with primary invasive breast cancer were included. Women with the lowest 25(OH)D levels (≤ 52 nmol/L) had an inferior EFS with a HR of 1.63 (95% CI 1.21-2.19) compared to women in the third quartile (76-99 nmol/L). Women with the highest 25(OH)D levels (≥ 99 nmol/L) also had an inferior EFS with a HR of 1.37 (95% CI 1.02-1.83). Plotting 25(OH)D status against EFS, the association was inversely J-shaped. For OS, a similar association with 25(OH)D status was observed.

CONCLUSION

We confirmed previous findings suggesting that a low 25(OH)D status is associated with an inferior breast cancer survival, but unlike previous findings, we found an indication of poorer breast cancer survival also among women with high 25(OH)D levels.

The Impact of Margin Status on Breast Conservation Rates

BACKGROUND

Contemporary data indicate that breast conservation treatment (BCT) results in superior survival outcomes compared with mastectomy. However, positive margins after lumpectomy have implications for local control, and re-excisions are recommended to achieve negative margins. The need for reoperations after an initial attempt at BCT is associated with higher chance of conversion to mastectomy. Achieving negative margins at the first therapeutic surgical procedure is therefore critical to optimise BCT rates and survival outcomes.

METHODS

A compilation of scientific reports on BCT, margin status, rates of reoperation, and the impact on BCT rates was reviewed. Re-excision rates after initial lumpectomy is variable to a staggering degree and reported to be between 0 and 100%. High reoperation rates (ROR) are associated with higher likelihood of conversion to mastectomy, which may not confer favourable treatment outcomes. Although widely agreed that decreasing ROR is a desirable objective, there is controversy regarding the need for its urgent implementation as a quality metric. Critics of this cite challenges related to how this can be achieved and its attendant ramifications. On the other hand, without the appropriate incentive for quality improvement of surgical treatment of breast cancer, patients may be subject to poorer overall outcomes.

DISCUSSION

Techniques and approaches are discussed in this article to enable a reduction in positive margin status, and therefore ROR. The rationale for achieving ROR of 10-20% are explicated, as well as the impact this would have on BCT rates, which translates to better survival outcomes for women with breast cancer.

Breast cancer mortality in synchronous bilateral breast cancer patients

Background

Evidence suggests that patients with synchronous bilateral breast cancer (SBBC), diagnosed within 4 months, have an inferior prognosis compared to unilateral breast cancer (UBC) patients. Using data from nationwide Danish clinical databases, this cohort study investigated whether the inferior prognosis could be explained by SBBC patients having a more aggressive disease, or whether the prognosis could be explained by the fact that they have two simultaneous cancers.

Methods

Patients were diagnosed from 1999–2015. The main outcome was excess mortality, subtracting background population mortality from observed mortality. Differences between SBBC and UBC patients were evaluated by rate ratios (RR) and estimated by Poisson regression.

Results

In total, 1214 SBBC and 59 177 UBC patients were included. SBBC patients had a significantly higher excess mortality than UBC patients after adjustment for age and period (RR = 1.73; 95% CI:1.44–2.08; p < 0.01) and after adjusting for characteristics of the worst tumour as traditionally done (RR = 1.31; 95% CI:1.08–1.57; p = 0.01). However, adjusting for characteristics of both tumours, using a more advanced competing risks model, no difference was observed (RR = 1.01; 95% CI:0.83–1.22; p = 0.93).

Conclusions

Our study does not support that the inferior prognosis in SBBC patients is due to having more aggressive tumours per se, but rather the combined effect of having two simultaneous cancers.

Expression of survivin does not appear to influence breast cancer recurrence risk

BACKGROUND

Survivin is an inhibitor of apoptosis, and its expression associates with poor outcomes in multiple cancers. It may be a therapeutic target due to its unique expression in cancer cells.

METHODS

We estimated the association between nuclear and cytoplasmic survivin expression in primary tumors and breast cancer recurrence. In this case-control study, we included women age 35-69, diagnosed with stage I-III breast cancer between 1985 and 2001, and registered with the Danish Breast Cancer Group. We identified 541 patients with breast cancer recurrence with estrogen receptor-positive disease who were treated with tamoxifen for at least 1 year (ER+/TAM+) and 300 with estrogen receptor-negative carcinomas, not treated with tamoxifen, and who survived at least 1 year (ER-/TAM-). Controls were matched to cases on ER/TAM status, date of surgery, menopausal status, stage and county. Survivin expression was estimated by immunohistochemistry on tissue microarrays. We fit logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (CIs) associating nuclear and cytoplasmic survivin expression with recurrence.

RESULTS

Associations between nuclear and cytoplasmic survivin expression and breast cancer recurrence were near-null in both ER+/TAM + and ER-/TAM - strata. For the cytoplasmic to nuclear ratio (CNR) of survivin expression, we found a null association in the ER+/TAM + group comparing CNR ≥5 with CNR <5, but an association (OR =2.48, 95% CI: 1.15, 5.31) in the ER-/TAM - group.

CONCLUSIONS

Survivin expression was not associated with breast cancer recurrence in this study. The CNR ratio may warrant further investigation especially among ER - tumors.