Projects

With incidence rates among the highest in Europe, breast cancer has to be considered as a public health priority in Switzerland. Bearing in mind the improved survival of older patients with breast cancer, an increase of older breast cancer survivors is expected in the coming years. A significant proportion of these patients will likely experience a decline in physical, cognitive or social functioning in the first years after diagnosis and treatment. Nevertheless, little is known about long-term symptom burden and its consequences for well-being of older breast cancer survivors. With the proposed cohort we aim to address this gap of knowledge for older Swiss early stage breast cancer survivors. 

Project lead: Esther Bastiaannet
Funding: Swiss Cancer League

To date, it is not clear whether novel treatment strategies in the last decades translated to an improvement of survival in older patients with metastatic breast cancer. This is an important issue, since older patients are more likely to be diagnosed with advanced or metastatic breast cancer compared to their younger counterparts. 
Treating older patients with metastatic breast cancer is challenging in many ways. Older patients represent a heterogeneous population, with large variations in comorbidity, geriatric syndromes, and functional status. 
The aim of this project consists of studying tumor characteristics, treatment, and survival for older patients from Switzerland with metastatic breast cancer at diagnosis.

Project lead: Esther Bastiaannet & Emanuel Mauch (External Co-lead)
Funding: Internal

The management of melanoma in the very old can involve complex decision making and is becoming an increasingly important issue for health care professionals as the population ages; the World Health Organization predicts that the number of people aged over 80 years will quadruple between 2000 and 2050. Compared to younger patients, decision-making is complicated by patient frailty, competing causes of mortality, medical comorbidities, and a reluctance by clinicians, patients and caregivers to undertake invasive procedures in persons who are at significant risk of complications and who may not survive long enough to obtain any benefit from the intervention. Observational studies show indeed that older patients present with poor prognosis melanomas, receive fewer diagnostic procedures, receive surgical management that deviates from guideline recommendations and have poorer outcomes, although data specifically focusing on the oldest old over 80 years is scarce. 
The aim of this study is to assess Breslow thickness, and survival for younger, older and the oldest Swiss patients with melanoma. In a sub-question we would like to assess immunotherapy over time for metastatic melanoma. 

Project lead: Juliette Preisig & Esther Bastiaannet (Co-lead)
Funding: Internal

This exploratory research investigates the potential for high-quality registry data, when combined with sophisticated analytical methods, to validate and extend clinical trial findings to real-world populations. We provide a first application of the target trial framework to data from the Dutch Melanoma Treatment Registry, demonstrating improved causal inference capabilities in comparative effectiveness analyses. This methodology suggests promising directions for developing more inclusive, evidence-based treatment approaches that could better serve diverse patient populations, particularly older adults who face different treatment considerations than typical trial participants 

Project lead: Dafne Sanchez & Esther Bastiaannet
Funding: Internal

Gastrointestinal stromal tumors (GISTs) are a rare type of sarcoma. Due to the low number of patients, clinical trials are lacking, especially for older patients. Therefore, observational studies play a key role by evaluating treatments strategies and survival in rare diseases in older patients. The present study aims to compare survival and treatment in patients aged 70 years and older diagnosed with GIST across five countries.
This is an observational retrospective study with older patients diagnosed with a GIST in Belgium, Italy, Netherlands, Norway and UK between 2002 and 2018. Treatment differences have been explored using descriptive tables and plots, stratified by stage. Multiple imputation (MI) by chained equation has been used to account for missingness in baseline variables. Relative survival (RS) has been estimated for each country by stage; univariate and multivariate models have been performed to obtain Relative excess risks (RERs) of death.

Project lead: Esther Bastiaannet & EURECCA
Funding: Internal

This study aimed to analyze recent trends in melanoma patients in the canton of Zurich, Switzer- land. An analysis was conducted to understand trends in tumour and patient characteristics as well as Breslow thickness (BT) and Relative Survival (RS). We will also conducted additional in-depth analyses specifically focusing on older patient groups.

Project lead: Esther Bastiaannet & Severin Spring (External Co-lead)
Funding: Internal

The most prevalent bone sarcomas are chondrosarcoma, osteosarcoma and Ewing sarcoma; aggressive treatment for high-grade bone sarcomas is warranted due to their rapid and invasive growth pattern and capabilities to metastasize. Adding chemotherapy to the treatment regimen contributed significantly to an increase in survival for patients with osteosarcoma and Ewing sarcoma. However, since the introduction three decades ago, survival of patients with osteosarcoma has reached a plateau in several European countries. Incidence, prognostic factors and survival for patients with chondrosarcoma, osteosarcoma and Ewing sarcoma have been described before for the USA (SEER data), the Netherlands and Italy, however to the best of our knowledge not for Switzerland. Interestingly, the cohorts from several hospitals in various countries show different treatment strategies and survival; even after the increasingly centralization of bone sarcoma care in larger centers. 
The aim of this study is to assess sarcoma characteristics at diagnosis, treatment and relative survival for younger, middle-aged and older patients diagnosed with chondrosarcoma, osteosarcoma or Ewing sarcoma. 

Project lead: Esther Bastiaannet & Pieter van Sint Truiden  (External Co-lead)
Funding: Internal

The optimal treatment and care for older patients diagnosed with pancreatic cancer remain uncertain. Clinical trials typically overlook older individuals and those with co-morbidities, conditions frequently accompanying older patients with pancreatic cancer. A significant number of older patients are diagnosed at an advanced stage, and the approach to treatment and survival outcomes varies, based on factors such as age, stage of cancer, and even geographical location. Addressing the question of whether older adults are less likely to receive treatment, a comprehensive systematic review and meta-analysis conducted in 2022 investigated age-related inequalities in the administration of first-line treatment for pancreatic cancer. Across the 18 papers incorporated in the study, a striking pattern emerged: in the majority of papers, less than 10% of older patients received treatment. Notably, advanced age exhibited a significant correlation with diminished receipt of both “any treatment”, surgery, and chemotherapy as a primary therapeutic approach. Conversely, treatment of pancreatic cancer entails inherent risks and side effects, thereby presenting a delicate balance between the potential for over and under treatment.
The aim of this study is to assess treatment and survival of Swiss older patients diagnosed with pancreatic cancer over time. 

Project lead: Esther Bastiaannet & Bo de Koning (External Co-lead)
Funding: Internal

Colorectal cancer (CRC) is ranked as the third most common neoplastic condition in men, following lung and prostate cancer, and the second most common in women after breast cancer. The incidence and mortality rate of CRC increases with age, and as life expectancy continues to rise, the proportion of older adults diagnosed with CRC is expected to grow.
Surgical resection remains the only curative treatment of colorectal cancer. Historically, surgical treatment options were not offered to older patients due to higher complications rates and an overall worse survival outcomes. However, advances in minimally invasive techniques and perioperative care have significantly reduced these risks. Dutch national data analyses show that the 30-day and one-year survival of older patients operated for colon cancer improved over time, though differences in short-term survival between younger and older populations remained. When assessing relative survival, defined as the ratio of observed survival to expected survival in a matched general population, older patients specifically had more excess mortality in the first post-operative year; after this year the outcomes were comparable to younger cohorts. 
The aim of this study is to assess the survival, by calculating the relative and conditional relative survival after one year, for different age groups in Swiss colon and rectal cancer patients. Secondary aim is to assess which patient and tumor characteristic are associated with the excess mortality in the first year after surgery (under the assumption that we find an higher excess mortality in older patient groups).  

Project lead: Esther Bastiaannet & Roman Zarbi (External Co-lead)
Funding: Internal

Older patients are often deemed ineligible for clinical research, and many frequently-used endpoints and outcome measures are not as relevant for older patients for younger ones. This systematic review aimed to present an overview of outcomes used in clinical research regarding patients over the age of 65 years with prostate cancer. 
PubMed and Embase were systematically searched to identify studies on prostate cancer (treatment) in patients aged ≥65 between 2016 and 2023. Data on title, study design, number of participants and age, stage of disease, treatment, and investigated outcomes were synthesized and descriptively analyzed.
Sixty-eight studies were included. Of these most included patients over 65 years, while others used a higher age. Overall, 39 articles (57.3%) reported on survival-related outcomes, 22 (32.4%) reported on progression of disease and 38 (55.9%) used toxicity or adverse events as an outcome measure. Health-related quality of life and functional outcomes were investigated in 29.4%, and cognition in two studies. The most frequently investigated survival-related outcomes were overall and cancer-specific survival (51.3%); however, 38.5% only studied overall survival. 
The main focus of studies included in this review remains survival and disease progression. There is limited attention for health-related quality of life and functional status, although older patients often prioritize the latter. Future research should incorporate outcome measures tailored to the aged population to improve care for older patients with prostate cancer.

Project lead: Esther Bastiaannet & Kim Jochems (Leiden University NL)
Funding: Internal

This systematic review comprehensively summarized frailty assessments used in observational studies of older women treated for breast cancer, revealing that few identified studies investigating survival after treatment account for frailty, with substantial variation in assessment methods limiting cross-study comparability. This study addresses a critical gap in oncology research by examining how frailty—a key determinant of health outcomes in older adults—is currently being measured and utilized in breast cancer survival studies. The findings illuminate critical deficiencies in how observational studies approach the complex health needs of older cancer patients, suggesting that current research may be providing incomplete or biased conclusions about treatment effectiveness.  

Project lead:  Dafne Sanchez & Esther Bastiaannet (Co-lead)
Funding: Internal