Robin Schaffar

Dr. Robin Schaffar

orcid

Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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24 December 2016 in European Journal of Cancer
Verified
Journal Article
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RSRobin Schaffar
Robin Schaffar
BRBernard Rachet
Bernard Rachet
ABAurelien Belot
Aurelien Belot
LWLaura M. Woods
Laura M. Woods
Net survival is the survival that would be observed if the only possible underlying cause of death was the disease under study. It can be estimated with either cause-specific or relative survival data settings, if the informative censoring is properly considered. However, net survival estimators are prone to specific biases related to the data setting itself. We examined which data setting was the most robust against violation of key assumptions (erroneous cause of death and inappropriate life tables). We identified 4285 women in the Geneva Cancer Registry, diagnosed with breast, colorectal, lung cancer and melanoma between 1981 and 1991 and estimated net survival up to 20 years using cause-specific and relative survival settings. We used weights to tackle informative censoring in both settings and performed sensitivity analyses to evaluate the impact of misclassification of cause of death in the cause-specific setting or of using inappropriate life tables on net survival estimates in the relative survival setting. For all the four cancers, net survival was highest when using the cause-specific setting and the absolute difference between the two estimators increased with time since diagnosis. The sensitivity analysis showed that (i) the use of different life tables did not compromise net survival estimation in the relative survival setting, whereas (ii) a small level of misclassification for the cause of death led to a large change in the net survival estimate in the cause-specific setting. The relative survival setting was more robust to the above assumptions violations and is therefore recommended for estimation of net survival.

11 April 2013 in BMC Urology
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Journal Article
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ERElisabetta Rapiti
Elisabetta Rapiti
RSRobin Schaffar
Robin Schaffar
CIChristophe Iselin
Christophe Iselin
RMRaymond Miralbell
Raymond Miralbell
MPMarie-Françoise Pelte
Marie-Françoise Pelte
CBChristine Bouchardy
Christine Bouchardy
In this population-based study, we investigated the degree of concordance between Gleason scores obtained from prostate biopsies and those obtained from prostatectomy specimens, as well as the determinants of biopsy understaging.

6 September 2019 in PLOS ONE
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Journal Article
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RSRobin Schaffar
Robin Schaffar
CBChristine Bouchardy
Christine Bouchardy
PCPierre Olivier Chappuis
Pierre Olivier Chappuis
ABAlexandre Bodmer
Alexandre Bodmer
SBSimone Benhamou
Simone Benhamou
ERElisabetta Rapiti
Elisabetta Rapiti
Breast cancer is the most frequently diagnosed cancer among women worldwide. Despite the fact that breast cancer is more frequent after fifty years of age, breast cancer among young women has recently drawn particular attention due to an increase in incidence in several western countries. With the exception of individuals with a high genetic risk, breast cancer occurring in younger women remains poorly understood. This project aims at investigating the patient, tumour and treatment characteristics as well as the long-term health outcomes of these women by evaluating numerous variables that were collected from their pathology and medical files, including the social environment, family history, fertility and pregnancy. We constituted a population-based cohort from the Geneva Cancer Registry of 1586 patients with breast cancer who were aged less than 46 years at the time of diagnosis. Breast cancer was diagnosed before the age of 35 years in 225 women (14.2%), between 35 and 39 years of age in 368 women (23.2%) and between 40 and 45 years of age in 993 women (62.6%). Most of the patients were diagnosed with luminal A or luminal B molecular subtypes (32.8 and 37.5%, respectively), stage I or II tumours (75.2%), and estrogen (74.8%) and progesterone (67.5%) positive receptors. During the study period, 16.7% of these women developed loco-regional recurrences and 25.4% developed distant metastases; the majority (66.3%) did not have a recurrence. Regarding mortality, 474 (29.9%) women died during the study period, 347 (73.2%) from breast cancer. The results of this study will help filling the knowledge gap about treatment of young breast cancer patients and having a child after breast cancer, and will provide clinicians and public health professionals’ with additional information to improve quality of care and decrease the impact of breast cancer in young women.

1 June 2015 in Cancer Epidemiology
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Journal Article
Open access
RSRobin Schaffar
Robin Schaffar
BRBernard Rachet
Bernard Rachet
ABAurelien Belot
Aurelien Belot
LWLaura Woods
Laura Woods
Both cause-specific and relative survival settings can be used to estimate net survival, the survival that would be observed if the only possible underlying cause of death was the disease under study. Both resulting net survival estimators are biased by informative censoring and prone to biases related to the data settings within which each is derived. We took into account informative censoring to derive theoretically unbiased estimators and examine which of the two data settings was the most robust against incorrect assumptions in the data. We identified 2489 women in the Geneva Cancer Registry, diagnosed with breast cancer between 1981 and 1991, and estimated net survival up to 20-years using both cause-specific and relative survival settings, by tackling the informative censoring with weights. To understand the possible origins of differences between the survival estimates, we performed sensitivity analyses within each setting. We evaluated the impact of misclassification of cause of death and of using inappropriate life tables on survival estimates. Net survival was highest using the cause-specific setting, by 1% at one year and by up to around 11% twenty years after diagnosis. Differences between both sets of net survival estimates were eliminated after recoding between 15% and 20% of the non-specific deaths as breast cancer deaths. By contrast, a dramatic increase in the general population mortality rates was needed to see the survival estimates based on relative survival setting become closer to those derived from cause-specific setting. Net survival estimates derived using the cause-specific setting are very sensitive to misclassification of cause of death. Net survival estimates derived using the relative-survival setting were robust to large changes in expected mortality. The relative survival setting is recommended for estimation of long-term net survival among patients with breast cancer.

10 July 2019 in BMC Urology
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Journal Article
Open access
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RSRobin Schaffar
Robin Schaffar
SPSamaksha Pant
Samaksha Pant
CBChristine Bouchardy
Christine Bouchardy
HSHyma Schubert
Hyma Schubert
ERElisabetta Rapiti
Elisabetta Rapiti
This paper describes the testicular cancer trends for incidence, survival, socio-economic status (SES) disparities and second cancer occurrence in Geneva, Switzerland, a high-risk population. We included all testicular germ-cell tumors recorded in the population-based Geneva cancer registry during the period 1970–2012. Changes in incidence trends were assessed using Joinpoint regression to calculate the annual percentage change (APC). Overall and cancer-specific survivals (OS, CSS) were estimated by Kaplan Meyer methods. To evaluate the risk of a second cancer we calculated the Standardized Incidence Ratios (SIR) using the Geneva population incidence rates. The average annual testicular cancer rate was 7.32/100 000 men, with a non-significant increasing trend during the study period. The highest rates were observed among men younger than 39 years. Despite a trend toward earlier diagnosis, 14% of patients were diagnosed at a late stage. Patients with non-seminoma tumours and patients with low SES were more often diagnosed with an advanced stage. Both OS and CSS improved during the study period but with strong differences by age, stage, morphology and SES. The risk for developing a second cancer was more than doubled. This risk was particularly high for a contralateral testicular cancer, bladder cancer and pancreatic cancer. Overall, there was no substantial increase in the incidence of testicular cancer in Geneva in recent decades, however the prognosis has improved. The high risk of developing a second cancer, the differences in stage at diagnosis and survival by SES, require enhanced awareness and surveillance by clinicians, patients and men in general.

30 April 2024 in Breast Cancer Research and Treatment
Verified
Journal Article
Open access
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RSRobin Schaffar
Robin Schaffar
SBSimone Benhamou
Simone Benhamou
PCPierre O. Chappuis
Pierre O. Chappuis
ERElisabetta Rapiti
Elisabetta Rapiti
Purpose: Breast cancer (BC) in women under 45 is rare yet often aggressive. We aim to analyze loco-regional recurrences (LR), distant recurrences (DR), second breast cancers, and mortality in young BC patients. Methods: We enrolled 776 women with non-metastatic BC ≤45 years diagnosed from 1970 to 2012. Variables included age, family history, tumor stage/grade, and treatment. We used multivariate Cox regression and competing risk models. Results: Among the participants, 37.0% were diagnosed before the age of 40. Most had stage I or II, grade II, ER- and PR-positive, HER2-negative tumors. Over a median follow-up of 8.7 years, 10.1% experienced LR, 13.7% developed DR, and 10.8% died, primarily due to BC. The majority of recurrences occurred within the first five years. Older age (>40) significantly reduced the risk of LR and DR. Advanced disease stage, certain surgical strategies, and positive margins increased DR risk. In the cohort diagnosed between 2001 and 2012, recent diagnosis, triple-negative cancer, and hormonal therapy were associated with reduced LR risk. Breast-conserving surgery appeared to offer protective effects against DR. Conclusion: This study highlights that BC in young women carries a significant risk of early recurrence, with age, tumor characteristics, and treatment modalities influencing outcomes. The findings emphasize the need for tailored treatment strategies for young BC patients, focusing on surgical precision and aggressive adjuvant therapy for high-risk cases. This research contributes valuable insights into managing BC in younger patients, aiding in improving long-term outcomes.