Risk factors for cancer of unknown primary: a literature review.

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.

Vegetable and fruit consumption and cancer of unknown primary risk: results from the Netherlands cohort study on diet and cancer.

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.

Alcohol consumption, cigarette smoking and cancer of unknown primary risk: Results from the Netherlands Cohort Study.

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.

Meat consumption and cancer of unknown primary (CUP) risk: results from The Netherlands cohort study on diet and cancer.

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.

Family history of cancer in first degree relatives and risk of cancer of unknown primary.

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.

Updated Incidence, Treatment and Survival of a Nationwide Cohort of Patients with Peritoneal Metastases of Unknown Origin.

The aim of this study was to investigate the incidence, treatment and survival of patients with peritoneal metastases (PM) of unknown origin. All Dutch patients diagnosed in 2017 and 2018 with PM of unknown origin (PM-CUP) were evaluated. Data were extracted from the Netherlands Cancer Registry (NCR). Patients with PM-CUP were categorized into the following histological subtypes: 1) adenocarcinoma, 2) mucinous adenocarcinoma, 3) carcinoid, 4) unspecified carcinoma and 5) other. Treatments were compared between the different histological subtypes in patients with PM-CUP. Overall survival (OS) was calculated using the Kaplan-Meier method for all patients with cancer of unknown origin and between histological subtypes in patients with PM-CUP. Significant differences in OS were assessed by using the log-rank test. In total, 3026 patients were diagnosed with cancer of unknown origin, 513 (17%) among them were diagnosed with PM-CUP. Most PM-CUP patients received best supportive care only (76%), whereas 22% received systemic treatment and 4% underwent metastasectomy. Median OS was 1.1 months for all patients with PM-CUP but varied from 0.6 months to 30.5 months depending on the underlying histology. In this study, PM-CUP were diagnosed in 17% of all patients with cancer of unknown primary and the reported survival in this cohort was extremely poor. Since survival differed among histological subtypes and recently more treatment options became available for a selected group of patients with peritoneal malignancies, it is of great importance to identify the histology of the metastases and whenever possible the primary tumor.

International consensus on the initial diagnostic workup of cancer of unknown primary.

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.

Adherence to the World Cancer Research Fund and the American Institute for Cancer Research lifestyle recommendations for cancer prevention and Cancer of Unknown Primary risk.

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.

Type 2 diabetes mellitus and cancer of unknown primary risk: results from the Netherlands Cohort Study.

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.

Anthropometry, physical activity and cancer of unknown primary (CUP) risk: Results from the Netherlands cohort study.

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.

A prostate cancer vaccine comprising whole cells secreting IL-7, effective against subcutaneous challenge, requires local GM-CSF for intra-prostatic efficacy.

A panel of cytokine-secreting RM-9 prostate cancer cells were tested as whole cell vaccines to determine their capacity to evoke an anti-prostate cancer immune response. In our model, vaccines secreting mGM-CSF or mIL-7 resulted in the highest increase in circulating T lymphocytes after vaccination, prolonged survival and, in a proportion of animals, tumor-free survival. Anti-tumor effects were more evident after a subcutaneous RM-9 challenge than after an intraprostatic challenge. However, when the RM-9/mGM-CSF cell line was used as intraprostatic tumor challenge, protection after RM-9/mIL-7 vaccination was restored.

ELVIRA HSV, a yield reduction assay for rapid herpes simplex virus susceptibility testing.

A colorimetric yield reduction assay, ELVIRA (enzyme-linked virus inhibitor reporter assay) HSV, was developed to determine the antiviral drug susceptibilities of herpes simplex virus (HSV). It uses an HSV-inducible reporter cell line. This simple and rapid assay has an objective readout, low inoculum size, and good reproducibility. The results correlate well with those of the plaque reduction assay.