Background/aim: Unknown primary tumour (UPT) is the term applied to metastatic cancer, the origin of which remains unidentified. Since cancer treatment is primarily based on the tumour site of origin, treatment of UPT patients is challenging. The number of reports on incidence, treatment and survival of UPT is limited. We hereby report data on patients (2000-2012) with UPT in the Netherlands.
Methods: The age-standardised rate (ASR) of 'other and unspecified' malignancies in the Netherlands was compared with other European countries. Patients diagnosed with UPT between 2000 and 2012 were selected from the Netherlands Cancer Registry (NCR) to calculate incidence rates. Patient characteristics, treatment and survival rates were assessed.
Results: The ASR of 'other and unspecified' malignancies in the Netherlands did not differ from the European average ASRs (2008-2012). A total of 29,784 patients with an unknown primary tumour were selected from the NCR (2000-2012). The incidence decreased from 14 per 100,000 person years (European standardised rate) in 2000 to 7.0 in 2012. The most common metastatic sites were liver, lymph nodes, bone and lung (42%, 22%, 16% and 14%, respectively), and approximately two-thirds of patients were diagnosed with metastases at a single site. One-third of the patients were treated; these were mainly younger patients. The overall median survival for all patients was 1.7 months. The median survival of untreated patients was 1.0 month and of treated patients 6.3 months.
Conclusion: The incidence of UPT between 2000 and 2012 is decreasing in the Netherlands, and one-third of these patients received treatment. Survival after diagnosis is limited to months rather than years.
Patients with carcinoma of unknown primary (CUP) present with metastatic disease without an identified primary tumour. The unknown site of origin makes the diagnostic work-up and treatment challenging. Since little information is available regarding diagnostic work-up and treatment in daily practice, we collected and analysed these in a patient cohort with regard to the recommendations of the national CUP guideline. Data of 161 patients diagnosed with CUP in 2014 or 2015 were extracted from the Netherlands Cancer Registry (NCR) and supplemented with diagnostic work-up information from patient files and analysed. Patients underwent an average of five imaging studies during the diagnostic phase (range 1-17). From the tests as recommended in the national guideline on CUP, a chest X-ray was most commonly performed (73%), whereas a PET-CT was done in one out of four patients (24%). Biopsies were taken in 86% of the study population, with Cytokeratin 7 being the most frequently tested histopathological marker (73%). Less than half of patients received therapy (42%). CUP patients undergo extensive diagnostic work-up. The performance status did not influence the extent of the diagnostic work-up in CUP patients, but it was an important factor for receiving treatment.
Purpose: Cancer of unknown primary (CUP) is a metastasised cancer for which no primary lesion could be identified during life. Research into CUP aetiology with respect to dietary factors is particularly scarce. This study investigates whether meat consumption is associated with CUP risk.
Methods: Data was utilised from the prospective Netherlands cohort study that includes 1,20,852 participants aged 55-69 years. All participants completed a self-administered questionnaire on diet and other cancer risk factors at baseline. Cancer follow-up was established through record linkage to the Netherlands Cancer Registry and the Dutch Pathology Registry. A total of 899 CUP cases and 4111 subcohort members with complete and consistent dietary data were available for case-cohort analyses after 20.3 years of follow-up. Multivariable adjusted hazard ratios (HRs) were calculated using proportional hazards models.
Results: We found a statistically significant positive association with beef and processed meat consumption and CUP risk in women (multivariable adjusted HR Q4 vs. Q1 1.47, 95% CI 1.04-2.07, Ptrend = 0.004 and Q4 vs. Q1 1.53, 95% CI 1.08-2.16, Ptrend = 0.001, respectively), and a non-significant positive association with processed meat consumption and CUP risk in men (multivariable adjusted HR Q4 vs. Q1 1.33, 95% CI 0.99-1.79, Ptrend = 0.15). No associations were observed between red meat (overall), poultry or fish consumption and CUP risk.
Conclusion: In this cohort, beef and processed meat consumption were positively associated with increased CUP risk in women, whereas a non-significant positive association was observed between processed meat consumption and CUP risk in men.
Cancer of unknown primary (CUP) is a metastasised malignancy with no identifiable primary tumour origin. Despite the frequent occurrence and bleak prognosis of CUP, research into its aetiology is scarce. Our study investigates alcohol consumption, tobacco smoking and CUP risk. We used data from the Netherlands Cohort Study, a cohort that includes 120 852 participants aged 55 to 69 years, who completed a self-administered questionnaire on cancer risk factors at baseline. Cancer follow-up was established through record linkage to the Netherlands Cancer Registry and Dutch Pathology Registry. After 20.3 years of follow-up, 963 CUP cases and 4288 subcohort members were available for case-cohort analyses. Multivariable-adjusted hazard ratios (HRs) were calculated using proportional hazard models. In general, CUP risk increased with higher levels of alcohol intake (Ptrend = .02). The association was more pronounced in participants who drank ≥30 g of ethanol per day (HR: 1.57, 95% confidence interval [CI]: 1.20-2.05) compared to abstainers. Current smokers were at an increased CUP risk (HR: 1.59, 95% CI: 1.29-1.97) compared to never smokers. We observed that the more the cigarettes or the longer a participant smoked, the higher the CUP risk was (Ptrend = .003 and Ptrend = .02, respectively). Interaction on additive scale was found for participants with the highest exposure categories of alcohol consumption and cigarette smoking frequency and CUP risk. Our findings demonstrate that alcohol consumption and cigarette smoking are associated with increased CUP risk. Lifestyle recommendations for cancer prevention regarding not drinking alcohol and avoiding exposure to smoking are therefore also valid for CUP.
Background: Cancer of Unknown Primary (CUP) is a metastatic disease for which the primary tumour origin could not be identified during life. Few studies have investigated the risk factors associated with this disease. This study investigates anthropometry, physical activity and CUP risk.
Methods: Data is used from the Netherlands Cohort Study, which includes 120,852 participants aged 55-69 years. All cohort members completed a self-administered questionnaire on cancer risk factors at baseline in 1986. Cancer follow-up was established through record linkage to the Netherlands Cancer Registry and the Dutch Pathology Registry. After a follow-up of 20.3 years, 926 incident CUP cases and 4099 subcohort members were available for case-cohort analyses. Proportional hazards models were used to compute multivariable adjusted hazard ratios (HRs).
Results: We found no associations between height, body mass index (BMI) at baseline, BMI at age 20 years, change in BMI since age 20 years, clothing size (trouser/skirt size), or non-occupational physical activity and CUP risk.
Conclusion: Our findings indicate that neither anthropometry nor physical activity are associated with the development of CUP.
Guidelines intend to provide the medical professional with a set of recommendations on the best standards of care. For carcinoma of unknown primary, a heterogeneous group of metastatic malignancies for which the site of origin is not detected, several guidelines are internationally available. Because each guideline is developed by a different committee with their own point of view, these guidelines might advise differently regarding diagnostic and treatment strategies for patients with a malignancy of unknown origin. Via an internet search, using the terms “guideline(s)”, “CUP” and “carcinoma unknown primary”, four guidelines were identified: the NCCN guideline from the USA, the SEOM guideline from Spain, the NICE guideline from the United Kingdom and the European guideline (ESMO), based in Switzerland. These guidelines and our national guideline used in The Netherlands, were compared and an overview was made of the differences and consistencies of the advised diagnostic, treatment and follow-up strategies.
Of the five compared guidelines, only one guideline (NICE) mainly focuses on the logistics with regard to patient care while other guidelines focus more on the diagnostic strategies to identify the primary tumor site. The described diagnostics sometimes show overlap but frequently differ on the various recommended diagnostic tools to identify the site of tumor origin such as PET, CT, MRI, IHC markers, ultrasound and endo-, colo-, colposcopy. For the treatment of patients with CUP the guidelines often refer to the guideline of the suspected primary tumor site. Only one guideline (NICE) generally refers to a multidisciplinary team to discuss the best possible treatment for the patient.
Numerous differences between the CUP guidelines were observed. These differences in diagnostic strategies, and the different diagnostic tools used, result in divergent perceptions regarding the definition of the term “carcinoma unknown primary” and makes comparison of incidence rates, survival times and treatment strategies challenging. International collaboration regarding evidence based guideline development might be of benefit for medical professionals and their patients.
Objective: Cancer of Unknown Primary (CUP) refers to the presence of metastatic lesions, with no identifiable primary site during the patient's lifetime. Poor survival and lack of available treatment highlight the need to identify potential CUP risk factors. We investigated whether a family history of cancer is associated with increased CUP risk.
Methods: We performed a case cohort analysis using data from the Netherlands Cohort Study, which included a total of 963 CUP cases and 4,288 subcohort members. A Cox Proportional Hazards Regression was used to compare CUP risk in participants who reported to have a family member with cancer to those who did not, whilst adjusting for confounders.
Results: In general, we observed no increased CUP risk in those who reported a family history of cancer. CUP risk appeared slightly increased in those who reported cancer in a sibling (HR: 1.16, 95% CI: 0.97-1.38), especially in those with a sister with cancer compared with those without (HR: 1.23, 95% CI: 0.99-1.53), although these findings are not statistically significant.
Conclusion: Having a family history of cancer is not an independent risk factor of CUP.
Cancer of Unknown Primary (CUP) is metastatic cancer with an unidentifiable primary tumour origin during life. It remains difficult to study the occurrence and aetiology of CUP. Hitherto, it is unclear whether risk factors are associated with CUP, yet identifying these factors could reveal whether CUP is a specific entity or a cluster of metastasised cancers from various primary tumour origins. Epidemiological studies on possible CUP risk factors were systematically searched in PubMed and Web of Science on February 1st, 2022. Studies, published before 2022, were included if they were observational human-based, provided relative risk estimates, and investigated possible CUP risk factors. A total of 5 case-control and 14 cohort studies were included. There appears to be an increased risk for smoking in relation to CUP. However, limited suggestive evidence was found to link alcohol consumption, diabetes mellitus, and family history of cancer as increased risks for CUP. No conclusive associations could be made for anthropometry, food intake (animal or plant-based), immunity disorders, lifestyle (overall), physical activity, or socioeconomic status and CUP risk. No other CUP risk factors have been studied. This review highlights smoking, alcohol consumption, diabetes mellitus and family history of cancer as CUP risk factors. Yet, there remains insufficient epidemiological evidence to conclude that CUP has its own specific risk factor profile.
Objective: Cancer of unknown primary (CUP) is a metastatic malignancy with an unidentifiable primary tumour origin. Previous studies suggest that type 2 diabetes mellitus (T2DM) and CUP risk are associated. This study examines the association in greater depth by investigating T2DM status, T2DM duration, T2DM age at diagnosis, and medication that was being used in relation to CUP.
Methods: Data were utilized from the Netherlands Cohort Study, a prospective cohort that includes 120 852 participants aged 55-69 years at baseline in 1986. All participants completed a self-administered questionnaire on cancer risk factors. CUP cases were identified through record linkage with the Netherlands Cancer Registry and Dutch Pathology Registry. After 20.3 years of follow-up, 963 incident CUP cases and 4288 subcohort members were available for case-cohort analyses. Proportional hazards models were employed to estimate multivariable-adjusted hazard ratios (HRs).
Results: Overall, we observed a nonsignificant positive association between T2DM status and CUP risk [HR, 1.35; 95% confidence interval (CI), 0.92-1.99], which increased in women after stratification for sex (HR, 1.55; 95% CI, 0.90-2.64). For participants who were aged less than 50 years at diagnosis of T2DM, a statistically significant positive association was found in relation to CUP (HR, 2.42; 95% CI, 1.26-4.65), compared with participants without T2DM.
Conclusion: Our findings indicate that there is a nonsignificant positive association between T2DM and CUP risk and that the association became stronger in women in stratified analyses.
Background & aims: The World Cancer Research Fund (WCRF) and American Institute for Cancer Research (AICR) updated their cancer prevention recommendations in 2018. Adherence to these recommendations has been associated with lower cancer risk and mortality. However, adherence in relation to Cancer of Unknown Primary (CUP) risk has not been studied. This study investigates whether adherence to the WCRF/AICR recommendations is associated with CUP risk.
Methods: Data from the prospective Netherlands Cohort Study on diet and cancer was used to measure adherence to the recommendations in relation to CUP risk. The cohort includes 120 852 participants (aged 55-69 years), who completed a self-administered questionnaire on cancer risk factors at baseline. Adherence was investigated with respect to body fatness, physical activity, plant foods, meat consumption and alcohol. Incident CUP cases were identified through record linkage to the Netherlands Cancer Registry and Dutch Pathology Registry. A follow-up of 20.3 years, resulted in 856 incident CUP cases and 3911 subcohort members with complete information available for case-cohort analyses. Multivariable adjusted hazard ratios were estimated using proportional hazards models and were adjusted for age at baseline, sex, cigarette smoking (status, frequency, and duration) and total energy intake.
Results: Highest adherence appeared to be associated with decreased CUP risk in the age-sex adjusted model (HR: 0.76, 95% CI: 0.62-0.92). After additional adjustment for cigarette smoking (status, frequency, and duration), the association attenuated and was no longer statistically significant. No multiplicative interactions were observed between sex nor smoking status and overall adherence in relation to CUP.
Conclusion: Within this cohort, highest adherence to the WCRF/AICR recommendations is not statistically significantly associated with decreased CUP risk after multivariable adjustment.
Keywords: Adherence; Cancer of Unknown Primary (CUP); Epidemiology; Lifestyle; Nutrition; Prospective cohort study.
Background: Cancer of Unknown Primary (CUP) is a metastatic cancer for which the primary lesion remains unidentifiable during life and little is also known about the modifiable risk factors that contribute to its development. This study investigates whether vegetables and fruits are associated with CUP risk.
Methods: We used data from the prospective Netherlands Cohort Study on Diet and Cancer which includes 120,852 participants aged between 55 and 69 years in 1986. All participants completed a self-administered questionnaire on cancer risk factors at baseline. Cancer follow-up was established through record linkage to the Netherlands Cancer Registry and the Dutch Pathology Registry. As a result, 867 incident CUP cases and 4005 subcohort members were available for case-cohort analyses after 20.3 years of follow-up. Multivariable adjusted hazard ratios were calculated using proportional hazards models.
Results: We observed no associations between total vegetable and fruit consumption (combined or as separate groups) and CUP risk. However, there appeared to be an inverse association between the consumption of raw leafy vegetables and CUP. With respect to individual vegetable and fruit items, we found neither vegetable nor fruit items to be associated with CUP risk.
Conclusions: Overall, vegetable and fruit intake were not associated with CUP incidence within this cohort.
Background: Although the incidence of Cancer of Unknown Primary (CUP) is estimated to be 1-2 % of all cancers worldwide, no international standards for diagnostic workup are yet established. Such an international guideline would facilitate international comparison, provide adequate incidence and survival rates, and ultimately improve care of patients with CUP.
Methods: Participants for a four round modified Delphi study were selected via a CUP literature search in PubMed and an international network of cancer researchers. A total of 90 CUP experts were invited, and 34 experts from 15 countries over four continents completed all Delphi survey rounds.
Findings: The Delphi procedure resulted in a multi-layer CUP classification for the diagnostic workup. Initial diagnostic workup should at least consist of history and physical examination, full blood count, analysis of serum markers, a biopsy of the most accessible lesion, a CT scan of chest/abdomen/pelvis, and immunohistochemical testing. Additionally, the expert panel agreed on the need of an ideal diagnostic lead time for CUP patients. There was no full consensus on the place in diagnostic workup of symptom-guided MRI or ultrasound, a PET/CT scan, targeted gene panels, immunohistochemical markers, and whole genome sequencing.
Interpretation: Consensus was reached on the contents of the first diagnostic layer of a multi-layer CUP classification. This is a first step towards full consensus on CUP diagnostics, that should also include supplementary and advanced diagnostics.
Purpose: Cancers of an unknown primary site (CUPs) have a dismal prognosis, and the situation is even worse for CUPs patients with brain metastases (BM-CUPs). This study aims to give better insight into the occurrence and survival of BM-CUPs patients.
Methods: Cases were selected from the Netherlands Cancer Registry (1,430 BM-CUPs/17,140 CUPs). Baseline characteristics between CUPs patients with and without BM were tested using chi-square tests and Mann-Whitney U tests. Patients' overall survival (OS) times were estimated by the Kaplan-Meier method and prognostic factors on OS was assessed using Cox proportional hazards regression analyses.
Results: The proportion of BM-CUPs patients among CUPs increased from 8% in 2009-2010 to 10% in 2017-2018 (p < 0.001). Most patients presented with multiple brain lesions (53%). Survival of BM-CUPs improved over time: one-year OS increased from 10% for patients diagnosed in 2009-2010 to 17% (2017- 2018) (p < 0.01), and median survival times increased from 1.8 months to 2.2 months. Independent predictors of poor survival were multiple (HR 1.25; p < 0.01) or unknown (HR 1.48; p < 0.01) locations of BM, unknown/poorly/undifferentiated carcinoma histology (HR 1.53; p < 0.01), or clinical symptoms of BM (HR 1.74; p < 0.01), accompanying liver metastasis (HR 1.43; p < 0.01) and more than one metastatic site outside the brain compared to none (HR 1.52; p < 0.01).
Conclusion: The incidence of patients with BM-CUPs is steadily increasing over time and overall prognosis remains dismal. Our results, however, show distinct patient subgroups that exhibit comparatively better outcomes, and more predictors may likely still be identified.
Background: Although patients with melanoma of unknown primary (MUP) have a better prognosis than similar-staged melanoma patients with known primary, the occurrence of brain metastases (BM) entails a serious complication. This study provides an overview of the incidence, treatment patterns, and overall survival (OS) of adult patients with BM-MUP in the Netherlands.
Methods: BM-MUP cases were retrieved from the Netherlands Cancer Registry. Patient, disease and treatment-related characteristics were summarised using descriptive statistics. Overall survival (OS) was calculated by the Kaplan-Meier method, and the impact of prognostic factors on OS was assessed using Cox proportional hazard regression analyses.
Results: Among 1779 MUP patients, 450 were identified as BM-MUP (25.3%). Of these patients, 381 (84.7%) presented with BM along with other metastases, while 69 (15.3%) had BM only. BM-MUP patients were predominantly male (68.2%), and had a median age of 64 years at diagnosis (interquartile range 54-71 years). Over time, the proportion of BM along other metastatic sites increased, and the occurrence of BM decreased (p = 0.01). 1-Year OS improved for the total population, from 30.0% (95% confidence interval (CI): 19.8-40.9%) in 2011-2012 to 43.6% (95%CI: 34.5-52.3%) in 2019-2020, and median OS more than doubled from 4.2 months (95%CI: 3.3-6.2 months) to 9.8 months (95%CI: 7.0-13.2 months). Patient's age, localisation of BM, presence of synchronous liver metastasis and treatment were identified as independent predictors of OS.
Conclusion: Notwithstanding the progress made in OS for patients with BM-MUP in the past decade, their overall prognosis remains poor, and further efforts are needed to improve outcomes.
CUP in the (inter)national news media
Het aantal patiënten met gemetastaseerd carcinoom waarbij de primaire tumor onbekend is, is tussen 2000 en 2012 gehalveerd. De overleving van deze patiënten is echter nog steeds heel laag, zo bleek uit onderzoek van dr. Caroline Loef van het Integraal Kankercentrum Nederland.
Er moet een landelijk beleid komen met bij voorkeur een expertpanel voor patiënten bij wie de diagnose primaire tumor onbekend (PTO) wordt gesteld, vinden dr. Caroline Loef, onderzoeker bij IKNL, en dr. Yes van de Wouw, internist-oncoloog bij het VieCuri Medisch Centrum. Behandelaars weten nu niet goed wat ze met deze patiënten aan moeten en door de onbekendheid van het ziektebeeld blijven patiënten en hun naasten met veel onzekerheden zitten.
Questions: 1-What do we know about CUP? 2-What do we know about the impact of genomic analysis in CUP diagnosis and treatment? 3-What standard diagnostic work-up is recommended to have completed, before a case can be called a CUP case? 4-Does speeding up the diagnostic process help patients’ outcome? 5-How doctors transfer the bad news about CUP diagnosis and outcome to the patients? Does support with palliative care helps CUP patients?