A Clinical Review of the Investigation and Management of Carcinoma of Unknown Primary in a Single Cancer Network

Management and prognosis of patients with cancer of unknown primary: 20 years of experience

Background/aim

Cancer of unknown primary (CUP) is a difficult clinical entity to manage. The aim of the study was to investigate the sociodemographic and pathological characteristics, treatment options, and factors affecting overall survival (OS) in CUP patients whose primary tumor was not detected during follow-up.

Materials and methods

A total of 243 CUP patients whose primary tumors could not be detected during follow-up were included in the study. Their demographic characteristics, survival outcomes, and prognostic factors were investigated.

Results

Of the 243 patients included in this study, 61.7% were male and 38.3% were female, and the median age was 61 (range: 19-90) years. The most common histological type was adenocarcinoma (79%). The median follow-up time of the patients was 30.3 months (95% CI: 11.4-49.3), the median OS time was 9.1 months (95% CI: 7.2-11.0), and 72.4% of the patients received at least 1 line of chemotherapy (CT). The difference in survival between the patients who did and did not receive CT was statistically significant (median OS: 10.1 vs. 4.2 months, p = 0.003). According to the multivariate analysis, the presence of cholestasis (HR: 0.48, 95% CI: 0.29-0.79, p = 0.004), lung metastasis (HR: 0.69, 95% CI: 0.51-0.95, p = 0.001), second-line chemotherapy (HR: 1.69, 95% CI: 1.14-2.49, p < 0.001), and Eastern Cooperative Oncology Group (ECOG) performance status (HR: 0.20, 95% CI: 0.10-0.40, p < 0.001) were independent prognostic factors influencing OS.

Conclusion

CUP patients who receive multiple lines of chemotherapy tend to have longer survival. This is the first study to report cholestasis as a prognostic factor in CUP patients. In addition, the presence of lung metastases, not receiving second-line chemotherapy, and ECOG performance status (≥2) were found to be independent poor prognostic factors.

Positive factors on survival of head and neck cancer of unknown primary: what the clinician can do

BACKGROUND

Management of patients with head and neck cancer of unknown primary (HNCUP) is challenging.

AIMS/OBJECTIVES

To provide a long-term analysis focusing on protective survival factors for clinical decision-making. Furthermore, the prognostic value of the current N classification system was evaluated.

MATERIAL AND METHODS

We retrospectively analyzed patients with HNCUP between 2003 and 2016. Univariate and multivariate analyses were used to investigate predictors of overall survival (OS).

RESULTS

A primary tumor was found in 67 of 290 patients with suspected HNCUP, leaving after exclusion 141 HNCUP cases for analysis, who received multi-step therapy (MST) (n = 108) or single therapy (n = 28). Chemotherapy (CT) (n = 101), curative MST, ≤3 positive lymph nodes (LN) (n = 33), squamous cell carcinoma (SCC) (n = 123), HPV+ (n = 21), M0 (n = 70) increased OS by 21.8%, 24.4%, 12.7%, 6.8%, 18.7%, 29.6%, respectively. 5- and 10-year OS was 78.1%/66.6%. The number of metastatic LNs predicted OS is better than N classification.

CONCLUSION AND SIGNIFICANCE

Aspects for clinical decision-making: Curative MST and SCC histology were the most significant predictors for improved OS. Categorizing LN into 1, 2-3, and >3 LNs was more significant than the traditional N classification. The addition of CT to curative MST has a stronger impact on survival than HPV and N classifications.

Evaluating DNA Methylation, Gene Expression, Somatic Mutation, and Their Combinations in Inferring Tumor Tissue-of-Origin

Carcinoma of unknown primary (CUP) is a type of metastatic cancer, the primary tumor site of which cannot be identified. CUP occupies approximately 5% of cancer incidences in the United States with usually unfavorable prognosis, making it a big threat to public health. Traditional methods to identify the tissue-of-origin (TOO) of CUP like immunohistochemistry can only deal with around 20% CUP patients. In recent years, more and more studies suggest that it is promising to solve the problem by integrating machine learning techniques with big biomedical data involving multiple types of biomarkers including epigenetic, genetic, and gene expression profiles, such as DNA methylation. Different biomarkers play different roles in cancer research; for example, genomic mutations in a patient’s tumor could lead to specific anticancer drugs for treatment; DNA methylation and copy number variation could reveal tumor tissue of origin and molecular classification. However, there is no systematic comparison on which biomarker is better at identifying the cancer type and site of origin. In addition, it might also be possible to further improve the inference accuracy by integrating multiple types of biomarkers. In this study, we used primary tumor data rather than metastatic tumor data. Although the use of primary tumors may lead to some biases in our classification model, their tumor-of-origins are known. In addition, previous studies have suggested that the CUP prediction model built from primary tumors could efficiently predict TOO of metastatic cancers (Lal et al., 2013; Brachtel et al., 2016). We systematically compared the performances of three types of biomarkers including DNA methylation, gene expression profile, and somatic mutation as well as their combinations in inferring the TOO of CUP patients. First, we downloaded the gene expression profile, somatic mutation and DNA methylation data of 7,224 tumor samples across 21 common cancer types from the cancer genome atlas (TCGA) and generated seven different feature matrices through various combinations. Second, we performed feature selection by the Pearson correlation method. The selected features for each matrix were used to build up an XGBoost multi-label classification model to infer cancer TOO, an algorithm proven to be effective in a few previous studies. The performance of each biomarker and combination was compared by the 10-fold cross-validation process. Our results showed that the TOO tracing accuracy using gene expression profile was the highest, followed by DNA methylation, while somatic mutation performed the worst. Meanwhile, we found that simply combining multiple biomarkers does not have much effect in improving prediction accuracy.

Integration of a patient-centred MUO/CUP service within a new acute oncology service: challenges and rewards

Background

Holistic approach to the clinical management pathway for malignancy of undefined primary origin (MUO)/carcinoma of unknown primary (CUP) patients remains an unmet clinical need. To address this, an MUO/CUP service was implemented during conception of a new acute oncology service (AOS).

Methodology

Over a comparable 17 months' duration, patient outcomes pre-MUO/CUP service implementation was retrospectively analysed and compared prospectively with post-service implementation database. Performance measures of MUO/CUP service were compared against national recommendations.

Results

In the retrospective cohort (n=32), median age was 71.5 years and median length of hospital stay (LOS) was 11.25 days. In the prospective cohort (n=42), median age was 75.5 years, median LOS was 7.75 days (p=0.037). Post-service implementation, 100% patients were discussed in MUO/CUP multidisciplinary team meeting; 96% of inpatient referrals were reviewed by oncology within 24-48 hours. In the prospective group, median overall survival (OS) was 73 days vs 35 days in the retrospective group (p=0.045; hazard ratio (HR) 1.61). Out of 20 patients suitable for anti-cancer treatment in the prospective group, 85% were treated within 31 days from the decision-to-treat; 90% were treated within 62 days of referral. Within the prospective group, median OS was 214 days in the treated sub-group, compared with 44 days in patients receiving best supportive care only (p<0.0001; HR 3.19).

Conclusion

Timely specialised input from AOS with a dedicated MUO/CUP team can achieve enhanced patient-centred and healthcare-centred outcomes, both in terms of survival and hospital stay. However, heterogeneity in both retrospective and prospective study groups, as well as discrepancies in coding, makes direct comparison between both groups challenging.

Extensive diagnostic work-up for patients with carcinoma of unknown primary

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.

Pembrolizumab plus platinum-based chemotherapy for unfavorable cancer of unknown primary site: Case report

INTRODUCTION

We report a case of sustained complete response in unfavorable cancer of unknown primary site (CUP) successfully treated with chemotherapy combining pembrolizumab, pemetrexed and platinum.

CASE PRESENTATION

A 66-year-old man was presented with weight loss and cough for 3 months. Contrast-enhanced computed tomography (CT) confirmed a mass in the superior anterior mediastinum and multiple enlarged mediastinal and axillary lymph nodes. Positron emission tomography-CT (PET-CT) showed abnormal uptake in the corresponding lesions. Histopathological analysis of the left axillary nodule revealed poorly differentiated adenocarcinoma. Immunohistochemistry showed the tumor cells were positive for cytokeratin 7 and thyroid transcription factor-1 and negative for cytokeratin 20. Thus, the patient was diagnosed as poorly differentiated adenocarcinoma of unknown primary, and treated as non-small-cell lung cancer. Additional genetic testing revealed the patient was negative for EGFR, ALK fluorescence in situ hybridization, ROS1, BRAF, and PD-L1 22C3 IHC with Tumor Proportion Score (TPS) was less than 1%. The patient received six cycles of pembrolizumab, platinum, and pemetrexed intravenously. Cisplatin was switched to carboplatin because of cisplatin nephrotoxicity in one course. PET-CT after six cycles showed all lesions disappeared; complete response was considered to have been achieved. Maintenance therapy of pembrolizumab and pemetrexed has been continued for 6 months after the induction therapies to prevent progressive disease. Complete response has been maintained.

DISCUSSION

Chemotherapy with pembrolizumab, platinum and pemetrexed could be valuable for treating unfavorable CUP.

CONCLUSION

Chemotherapy with pembrolizumab, platinum, and pemetrexed helped achieved sustained complete response in a patient with unfavorable CUP.

Predicting Cancer Tissue-of-Origin by a Machine Learning Method Using DNA Somatic Mutation Data

Patients with carcinoma of unknown primary (CUP) account for 3-5% of all cancer cases. A large number of metastatic cancers require further diagnosis to determine their tissue of origin. However, diagnosis of CUP and identification of its primary site are challenging. Previous studies have suggested that molecular profiling of tissue-specific genes could be useful in inferring the primary tissue of a tumor. The purpose of this study was to evaluate the performance somatic mutations detected in a tumor to identify the cancer tissue of origin. We downloaded the somatic mutation datasets from the International Cancer Genome Consortium project. The random forest algorithm was used to extract features, and a classifier was established based on the logistic regression. Specifically, the somatic mutations of 300 genes were extracted, which are significantly enriched in functions, such as cell-to-cell adhesion. In addition, the prediction accuracy on tissue-of-origin inference for 3,374 cancer samples across 13 cancer types reached 81% in a 10-fold cross-validation. Our method could be useful in the identification of cancer tissue of origin, as well as the diagnosis and treatment of cancers.

TOOme: A Novel Computational Framework to Infer Cancer Tissue-of-Origin by Integrating Both Gene Mutation and Expression

Metastatic cancers require further diagnosis to determine their primary tumor sites. However, the tissue-of-origin for around 5% tumors could not be identified by routine medical diagnosis according to a statistics in the United States. With the development of machine learning techniques and the accumulation of big cancer data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO), it is now feasible to predict cancer tissue-of-origin by computational tools. Metastatic tumor inherits characteristics from its tissue-of-origin, and both gene expression profile and somatic mutation have tissue specificity. Thus, we developed a computational framework to infer tumor tissue-of-origin by integrating both gene mutation and expression (TOOme). Specifically, we first perform feature selection on both gene expressions and mutations by a random forest method. The selected features are then used to build up a multi-label classification model to infer cancer tissue-of-origin. We adopt a few popular multiple-label classification methods, which are compared by the 10-fold cross validation process. We applied TOOme to the TCGA data containing 7,008 non-metastatic samples across 20 solid tumors. Seventy four genes by gene expression profile and six genes by gene mutation are selected by the random forest process, which can be divided into two categories: (1) cancer type specific genes and (2) those expressed or mutated in several cancers with different levels of expression or mutation rates. Function analysis indicates that the selected genes are significantly enriched in gland development, urogenital system development, hormone metabolic process, thyroid hormone generation prostate hormone generation and so on. According to the multiple-label classification method, random forest performs the best with a 10-fold cross-validation prediction accuracy of 96%. We also use the 19 metastatic samples from TCGA and 256 cancer samples downloaded from GEO as independent testing data, for which TOOme achieves a prediction accuracy of 89%. The cross-validation validation accuracy is better than those using gene expression (i.e., 95%) and gene mutation (53%) alone. In conclusion, TOOme provides a quick yet accurate alternative to traditional medical methods in inferring cancer tissue-of-origin. In addition, the methods combining somatic mutation and gene expressions outperform those using gene expression or mutation alone.

Diagnostic and health service pathways to diagnosis of cancer-registry notified cancer of unknown primary site (CUP)

Background

Cancer of unknown primary (CUP) is a late-stage malignancy with poor prognosis, but we know little about what diagnostic tests and procedures people with CUP receive prior to diagnosis. The purpose of this study was to determine how health service utilisation prior to diagnosis for people with cancer-registry notified CUP differs from those notified with metastatic cancer of known primary.

Methods

We identified people with a cancer registry notification of CUP (n = 327) from the 45 and Up Study, a prospective cohort of 266,724 people ≥45 years in New South Wales, Australia, matched with up to three controls with a diagnosis of metastatic cancer of known primary (n = 977). Baseline questionnaire data were linked to population health data to identify all health service use, diagnostic tests, and procedures in the month of diagnosis and 3 months prior. We used conditional logistic regression to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

Results

After adjusting for age and educational attainment, people with a cancer-registry notified CUP diagnosis were more likely to be an aged care resident (OR = 2.78, 95%CI 1.37–5.63), have an emergency department visit (OR = 1.65, 95%CI 1.23–2.21), serum tumor marker tests (OR = 1.51, 95%CI 1.12–2.04), or a cytology test without immunohistochemistry (OR = 2.01, 95%CI 1.47–2.76), and less likely to have a histopathology test without immunohistochemistry (OR = 0.43, 95%CI 0.31–0.59). Neither general practitioner, specialist, allied health practitioner or nurse consultations, hospitalisations, nor imaging procedures were associated with a CUP diagnosis.

Conclusions

The health service and diagnostic pathway to diagnosis differs markedly for people notified with CUP compared to those with metastatic cancer of known primary. While these differences may indicate missed opportunities for earlier detection and appropriate management, for some patients they may be clinically appropriate.

Circulating MiR-210 and MiR-1246 as Potential Biomarkers for Differentiating Hepatocellular Carcinoma from Metastatic Tumors in the Liver

Background

To date few reports have pointed out the role of circulating miRNAs in discriminating metastatic liver tumors from primary hepatocellular (HCC) tumors. Such discrimination will have significant therapeutic and prognostic implications. The purpose of this study was to evaluate the potential value of a panel of HCC-related circulating miRNAs (miR-142, miR-182, miR-200a, mir-210, miR-211, miR-302b, miR-324, miR-338, miR-340 and miR-1246) as noninvasive biomarkers for discriminating primary HCC from metastatic tumors in the liver.

Methods

The expression level of the selected miRNAs was quantified by quantitative real time PCR in 33 patients with HCC, 22 patients with metastatic tumors in the liver, and 30 healthy volunteers as control. Mann-Whitney U test was used to evaluate the difference in miRNAs expression between primary and metastatic liver tumors and to study the associations between their relative expression levels and the clinicopathological factors. Receiver operating characteristic curve was used to evaluate the diagnostic value of the individual miRNAs.

Results

Statistical analyses revealed a differential expression in the level of serum miR-210 and miR-1246 between the two groups of patients. The sensitivity and specificity of miR-210, for differentiating HCC from metastatic malignancies in the liver were found to be 73.7% and 64.28%, respectively. Whilst, of miR-1246 were 72.2% and 67.8%, respectively. In addition, the differential expression of the two miRNAs was also found to be associated with clinicopathological parameters in the two studied groups.

Conclusions

Serum miR-210 and miR-1246 have some diagnostic value for discriminating patients with metastatic tumors to patients with primary HCC

Prognostic Factors in Cancer of Unknown Primary Site

Aims and background

Patients with cancer of an unknown primary site (CUP) usually have a poor outcome. The identification of prognostic factors that affect survival can help clinicians find a better approach to such cases in terms of diagnostic and therapeutic management.

Methods

We conducted a retrospective study including the cases of CUP recorded at the University Hospital 12 de Octubre Tumor Registry between 1999 and 2003.

Results

CUP was diagnosed in 265 patients during the analyzed period. One hundred and seventy-one were men (64.5%) and the mean age of the patients was 66.9 years (range 32–98 years). The median survival was 2.5 months, and the survival rate was 35.1% 6 months from diagnosis (95% CI: 28.9–41.3) and 24.5% 1 year from diagnosis (95% CI: 18.7–30.3). Univariate analysis revealed as significant predictive variables of a better outcome age under 70 years; involvement of a single organ; normal serum levels of alkaline phosphatase and albumin; normal erythrocyte sedimentation rate; normal levels of the serum tumor markers CEA, CA 19.9 and CA 15.3; squamous carcinoma histology; clinical presentation as lymph node enlargement; and the administration of treatment. Multivariate analysis showed that albumin and alkaline phosphatase levels, squamous carcinoma histology, age and treatment were the most important prognostic factors. Other variables analyzed (liver, bone or lung involvement, lactate dehydrogenase levels, gender) did not affect survival.

Conclusions

CUP has a poor prognosis. Some prognostic factors that affect survival in these patients, however, may be identified.

Implementation of a metastatic malignancy of unknown primary origin service led by a palliative physician

BACKGROUND

Cancer of unknown primary is the fourth most common cause of cancer death in the United Kingdom. National guidance in 2010 recommended the establishment of a dedicated unknown primary team to facilitate targeted investigation and symptom control. A service development project was undertaken to identify those affected by malignancy of unknown origin and institute a pathway for coordinating their care led by a palliative physician.

METHOD

In order to describe the patient population and illness trajectory and to assess the effect of the new pathway on the clinical outcomes we used a retrospective and prospective comparative case notes survey to identify the pre- and post-pathway population. This took place in secondary care. Inclusion criteria were patients with metastatic disease with no known primary; exclusion criteria were where the site of metastasis was so suggestive of a primary that it would be managed as per that disease process. 88 patients were included.

RESULTS

Mean age was 72.5 years. The mean survival time from presentation was 81.8 days. There was no difference pre or during pathway implementation in age, performance status or survival time. There was no reduction in the numbers referred for tumour directed therapy. There was a non-statistically significant reduction in the number who died in hospital during the pathway implementation.

CONCLUSIONS

This study suggests having a metastatic malignancy of unknown primary origin service led by a palliative physician does not reduce the number referred for tumour directed therapy. It also adds evidence of the poor prognosis and thus the need for early palliative care input.

Perceptions of cancer of unknown primary site: a national survey of Australian medical oncologists

BACKGROUND

Despite being the sixth most common cause of cancer death in Australia, cancer of unknown primary (CUP) site remains poorly understood.

AIMS

To describe practices relating to the diagnosis, investigation, classification, communication and management of CUP among medical oncologists.

METHODS

We invited all members of the Medical Oncology Group of Australia to participate in a national, anonymous online survey about CUP. The survey collected data regarding diagnosis acceptance, diagnostic tests, treatment protocols and communication practices around the diagnosis of CUP.

RESULTS

Three hundred and two oncologists were invited and 86 (28%) completed the survey. Eighty (93%) respondents were directly involved in the assessment of patients with CUP. Eighty-five (99%) respondents were prepared to make a diagnosis of CUP if, after appropriate diagnostic tests, the primary location could not be ascertained. Eighty-three percent would assign a primary site to obtain Pharmaceutical Benefits Schedule funding of medical therapy. Sixty-two percent did not have a specific treatment protocol designed for CUP. The majority of oncologists used serum tumour markers and computed tomography scans in the initial work-up, while 43% indicated they would use a positron emission tomography scan in the majority of cases. The majority would arrange mammography in female patients. Thematic analysis of responses to open-ended questions about how CUP is described identified little consistency in the language being used.

CONCLUSION

The approach to diagnosis, investigation and management of CUP by medical oncologists in Australia is variable. Many preferred to estimate the primary site and treat accordingly. Pharmaceutical Benefits Schedule restrictions may encourage the practice of 'best guessing'.

Predictors of care for patients with cancer of unknown primary site in three Australian hospitals

AIM

Cancer of unknown primary site (CUP) is a medically challenging malignancy with a poor prognosis. We describe an incident tertiary CUP patient cohort and identify factors predictive of specific types of health care.

METHODS

We reviewed the medical records of 217 patients diagnosed with CUP (2006-2011) in three public hospitals in New South Wales, Australia. We systematically abstracted data and performed multivariable logistic regression to identify factors predictive of tumor biopsy, surgery, chemotherapy, radiotherapy and palliative care.

RESULTS

The median age at CUP diagnosis was 75 years (range 23-98) and 52% were male. The most common mode of presentation was emergency department admission (57%). Serum tumor markers were performed in 42%, fine needle aspiration alone in 15% and core biopsy in 52%. Younger age, health service referral, oncologist review and a family history of cancer predicted receipt of a biopsy (77%). Cancer-related surgery (17%) was more likely in younger patients, those presenting with pain, and those with single lymph node metastases. Younger age and good performance score predicted receipt of chemotherapy (22%). The location of metastases predicted receipt of radiotherapy (28%). Older age, emergency presentation, poor performance score and no oncology review predicted receipt of palliative care only (52%); 77% were referred for palliative care during hospitalization.

CONCLUSION

The determinants of care were generally consistent with international CUP clinical guidelines. Areas of future research include potential underinvestigation and undertreatment of older patients, overuse of certain low-value diagnostic tests, suboptimal use of immunohistochemistry and mammography and underreferral to palliative care.

A naive Bayes algorithm for tissue origin diagnosis (TOD-Bayes) of synchronous multifocal tumors in the hepatobiliary and pancreatic system

Synchronous multifocal tumors are common in the hepatobiliary and pancreatic system but because of similarities in their histological features, oncologists have difficulty in identifying their precise tissue clonal origin through routine histopathological methods. To address this problem and assist in more precise diagnosis, we developed a computational approach for tissue origin diagnosis based on naive Bayes algorithm (TOD-Bayes) using ubiquitous RNA-Seq data. Massive tissue-specific RNA-Seq data sets were first obtained from The Cancer Genome Atlas (TCGA) and ∼1,000 feature genes were used to train and validate the TOD-Bayes algorithm. The accuracy of the model was >95% based on tenfold cross validation by the data from TCGA. A total of 18 clinical cancer samples (including six negative controls) with definitive tissue origin were subsequently used for external validation and 17 of the 18 samples were classified correctly in our study (94.4%). Furthermore, we included as cases studies seven tumor samples, taken from two individuals who suffered from synchronous multifocal tumors across tissues, where the efforts to make a definitive primary cancer diagnosis by traditional diagnostic methods had failed. Using our TOD-Bayes analysis, the two clinical test cases were successfully diagnosed as pancreatic cancer (PC) and cholangiocarcinoma (CC), respectively, in agreement with their clinical outcomes. Based on our findings, we believe that the TOD-Bayes algorithm is a powerful novel methodology to accurately identify the tissue origin of synchronous multifocal tumors of unknown primary cancers using RNA-Seq data and an important step toward more precision-based medicine in cancer diagnosis and treatment.

Cancer of unknown primary: Registered procedures compared with national integrated cancer pathway for illuminating external validity

Cancer of unknown primary (CUP) ranges within top 10 cancers in both incidence and mortality. As primary identification is crucial to choosing treatment, guidelines on CUP emphasize the diagnostic strategy. Whether guidelines are complied with, or if they are indeed helpful, is however unclear. We compared procedures performed in suspected CUP patients with recommendations of national guidelines to assess external validity of guidelines.The Danish National Patient Registry (NPR) comprising population data was utilized to identify the suspected CUP patients during 2009 to 2010 and explore exposure to procedures and patient survival. The cohort was investigated in terms of validity of diagnosis through cross-referencing with the Cancer Registry (CR), which served as gold standard for cancer diagnoses and patients' cancer histories.The NPR cohort consisted of 542 patients (275 males, 264 females) of whom 210 (38.7%) had a CUP diagnosis confirmed. Within the cohort, 347 patients (64.0%) had a registration in CR matching with the NPR registration. Exposure to diagnostic procedures included biopsy (n = 439, 81.0%) and image modalities (n = 532, 98.2%). Survival was poor with 67 (12.4%) individuals alive after 4 years.The validity of a CUP diagnosis in NPR was low when using data from CR as reference. More than half the suspected CUP patients had a previous cancer diagnosis with CUP being the most frequent. Patients were diagnosed in compliance with guidelines indicating high external validity, but less than 1 quarter had their primary identified and the 1-year survival was approximately 20%. Research is needed to develop efficacious methods for primary detection.

A nucleic acid logic gate system that distinguishes different sets of inputs from one miRNA collection with shared members

A proof-of-principle logic system was established to process multi-input and multi-output logic relationships with the aim of identifying the tissue origins of cancer in light of their established relationships with miRNA distributions.

Unknown primary adenocarcinomas: a single-center experience

This study aimed to elucidate the clinical and prognostic characteristics of a homogeneous group of patients with cancer of unknown primary (CUP). Between 1999 and 2014, CUP was diagnosed in 159 (1.3%) of 11,742 cancer patients at Trakya University Hospital (Edirne, Turkey). Ninety-seven (61%) of the 159 patients were retrospectively reviewed. Among these, 61 (62.8%) patients with adenocarcinoma were included in this study. The most frequently predicted primary tumor site was the lung (37.7%), and 59% of the patients were smokers. There was a significant relationship between smoking and the lung as a potential primary cancer site (p = 0.042). The most frequent site of metastasis was the liver (60.7%). The median number of metastases per patient was two, but patients with liver metastases had a median of five metastases. The overall median survival time was 7 months. Median survival was significantly longer in patients with a predicted primary site than in patients without the predicted site (7 vs. 6 months, respectively; p = 0.038). When the patients with predicted ovarian and peritoneal tumors were excluded from the comparison, the statistical p value was still close to significant (p = 0.07). Multivariate analysis revealed that smoking, liver metastasis, serum alkaline phosphatase ≥92 U/L, and progression in response to chemotherapy were independent predictors of a poor prognosis. The present study identified several independent prognostic factors in patients with unknown primary adenocarcinomas who received chemotherapy. Smoking, the presence of liver metastasis, and response to chemotherapy were independent risk factors for both progression-free and overall survival.

Psychological burden on patients with cancer of unknown primary: from onset of symptoms to initial treatment

OBJECTIVE

Supportive care is a critical issue especially for patients with cancer of unknown primary since they often face serious situations, continuing to seek for relevant diagnosis and treatment with the primary sites unknown. However, there are only few research reports on this subject. The aim of this study was to clarify the experience on patients with cancer of unknown primary until they have their initial treatment and to obtain suggestions of supportive care for them.

METHODS

A qualitative study using semi-structured interviews regarding the experience on patients with cancer of unknown primary was conducted.

RESULTS

Data of the experience of the nine patients with cancer of unknown primary until their initial treatment were collected by semi-structured interviews. Patients' speech at interviews recorded in verbatim reports was assigned with 545 codes, 102 subcategories and 38 categories. Experience of the patients with cancer of unknown primary was categorized into five phases: Phase 1: period of making self-judgment on symptoms; Phase 2: period of suspecting serious disease, and seeking for appropriate medical treatment; Phase 3: period of searching for cause of disease while having painful symptoms and anxiety; Phase 4: period of having fear for death, frustration with unknown cause and denial of unknown state; Phase 5: period of struggling but being determined to face disease.

CONCLUSIONS

Experience of patients with cancer of unknown primary from onset of symptoms to their initial treatment was categorized into five phases, mainly manifesting their psychological burden. These findings will warrant for the future study of supportive care for patients with cancer of unknown primary.

A Simple Risk Model to Predict Survival in Patients With Carcinoma of Unknown Primary Origin

Carcinoma of unknown primary origin (CUP) is characterized by diverse histological subtypes and clinical presentations, ranging from clinically indolent to frankly aggressive behaviors. This study aimed to identify prognostic factors of CUP and to develop a simple risk model to predict survival in a cohort of Asian patients.We retrospectively reviewed 190 patients diagnosed with CUP between 2007 and 2012 at a single medical center in Taiwan. The clinicopathological parameters and outcomes of our cohort were analyzed. A risk model was developed using multivariate logistic regression and a prognostic score was generated.The prognostic score was calculated based on 3 independent prognostic variables: the Eastern Cooperative Oncology Group (ECOG) scale (0 points if the score was 1, 2 points if it was 2-4), visceral organ involvement (0 points if no involvement, 1 point if involved), and the neutrophil-to-lymphocyte ratio (0 points if ≤3, 1 point if >3). Patients were stratified into good (score 0), intermediate (score 1-2), and poor (score 3-4) prognostic groups based on the risk model. The median survival (95% confidence interval) was 1086 days (500-1617, n = 42), 305 days (237-372, n = 75), and 64 days (44-84, n = 73) for the good, intermediate, and poor prognostic groups, respectively. The c-statistics using the risk model and ECOG scale for the outcome of 1-year mortality were 0.80 and 0.70 (P = 0.038), respectively.In this study, we developed a simple risk model that accurately predicted survival in patients with CUP. This scoring system may be used to help patients and clinicians determine appropriate treatments.

Health service utilisation and investigations before diagnosis of cancer of unknown primary (CUP): A population-based nested case-control study in Australian Government Department of Veterans' Affairs clients

BACKGROUND

Population-based data on the use of health services and diagnostic investigations for patients with cancer of unknown primary (CUP) is scarce. It is uncertain whether the pathways to diagnosis are different for CUP compared to other cancers.

METHODS

We performed a population-based nested matched case-control study using linked routinely collected records for Australian Government Department of Veterans' Affairs clients, 2004-2007. We compared health care consultations, hospitalisations, emergency department visits, and diagnostic procedures in the three months prior and the month of diagnosis for 281 clients registered with a diagnosis of CUP (C809) and 1102 controls randomly selected from clients registered with a first diagnosis of metastatic cancer of known primary.

RESULTS

Overall, the median age at cancer diagnosis was 83 years. CUP patients were slightly older and had significantly more comorbidities prior to diagnosis than those with known primary. Compared to known primary, a diagnosis of CUP was significantly more likely after an emergency department visit, less specialist input, fewer invasive diagnostic procedures such as resection or endoscopy, and more non-invasive procedures such as magnetic resonance imaging. There were no differences in primary care or allied health consultations and hospitalisations.

CONCLUSIONS

This health care pathway suggests delayed recognition of cancer and scope for improvement in the medical management of high-risk individuals presenting to primary care. The pattern of diagnostic investigations reveals under-investigation in some CUP patients but this is likely to reflect recognition of limited treatment options and poor prognosis and is consistent with clinical guidelines.

RNA-Seq accurately identifies cancer biomarker signatures to distinguish tissue of origin

Metastatic cancer of unknown primary (CUP) accounts for up to 5% of all new cancer cases, with a 5-year survival rate of only 10%. Accurate identification of tissue of origin would allow for directed, personalized therapies to improve clinical outcomes. Our objective was to use transcriptome sequencing (RNA-Seq) to identify lineage-specific biomarker signatures for the cancer types that most commonly metastasize as CUP (colorectum, kidney, liver, lung, ovary, pancreas, prostate, and stomach). RNA-Seq data of 17,471 transcripts from a total of 3,244 cancer samples across 26 different tissue types were compiled from in-house sequencing data and publically available International Cancer Genome Consortium and The Cancer Genome Atlas datasets. Robust cancer biomarker signatures were extracted using a 10-fold cross-validation method of log transformation, quantile normalization, transcript ranking by area under the receiver operating characteristic curve, and stepwise logistic regression. The entire algorithm was then repeated with a new set of randomly generated training and test sets, yielding highly concordant biomarker signatures. External validation of the cancer-specific signatures yielded high sensitivity (92.0% ± 3.15%; mean ± standard deviation) and specificity (97.7% ± 2.99%) for each cancer biomarker signature. The overall performance of this RNA-Seq biomarker-generating algorithm yielded an accuracy of 90.5%. In conclusion, we demonstrate a computational model for producing highly sensitive and specific cancer biomarker signatures from RNA-Seq data, generating signatures for the top eight cancer types responsible for CUP to accurately identify tumor origin.

[Radiological diagnostics in CUP syndrome]

CLINICAL/METHODICAL ISSUE

Imaging plays an essential role in the therapeutic management of cancer of unknown primary (CUP) patients for localizing the primary tumor, for the identification of tumor entities for which a dedicated therapy regimen is available and for the characterization of clinicopathological subentities that direct the subsequent diagnostic and therapeutic strategy.

STANDARD RADIOLOGICAL METHODS

Modalities include conventional x-ray, computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound as well as positron emission tomography (PET)-CT and MRI-PET.

PERFORMANCE

In whole body imaging CT has a high sensitivity for tumor entities which frequently present as a metastasized cancer illness. According to the current literature CT is diagnostic in 86% of patients with pancreatic carcinoma, in 36% of patients with colon carcinoma and in 74% of patients with lung carcinoma. Additionally a meta-analysis showed that for patients with squamous cell carcinoma and cervical lymph node metastases a positive diagnosis was possible in 22% of the cases using CT, in 36% using MRI and in 28-57% using 18F-fluorodeoxyglucose PET-CT ((18)F-FDG PET-CT). In addition, MRI plays an important role in the localization of primary occult tumors (e.g. breast and prostate) because of its high soft tissue contrast and options for functional imaging.

ACHIEVEMENTS

At the beginning of the diagnostic algorithm stands the search for a possible primary tumor and CT of the neck, thorax and abdomen is most frequently used for whole body staging. Subsequent organ-specific imaging examinations follow, e.g. mammography in women with axillary lymphadenopathy. For histological and immunohistochemical characterization of tumor tissue, imaging is also applied to identify the most accessible and representative tumor manifestation for biopsy. Tumor biopsy may be guided by CT, MRI or ultrasound and MRI also plays a central role in the localization of primary occult tumors because of superior soft tissue contrast and options for functional imaging (perfusion, diffusion), e.g. investigation of breast carcinoma or prostate carcinoma.

PRACTICAL RECOMMENDATIONS

Whole body staging stands at the beginning of the diagnostic algorithm in CUP syndrome to localize a potential primary tumor. Clinically, contrast-enhanced CT of the neck, thorax and abdomen is frequently applied; however, many studies have demonstrated augmented sensitivity of (18)F-FDG PET-CT for the detection of primary tumors and metastatic tumor manifestations.

Metastatic Tumors of Unknown Origin: Ancillary Testing in Cytologic Specimens

The application of ancillary studies, such as immunostains, to cytopathology has improved the ability to make accurate diagnoses with precise subclassification. Even with these techniques, there are still aspiration and exfoliative cytology cases for which it remains difficult to definitively determine the source and/or subtype. This article focuses on the well-established and novel ancillary studies used in the modern era of cancer diagnoses in cytopathology, particularly in the diagnostic work-up of metastatic tumors without a known primary.

[Metastatic thoracic lymph node carcinoma from extra-thoracic malignancy or from unknown primary site]

Malignant mediastinal lymph nodes without pulmonary disease may be lymphomatous or the metastases from thoracic or extrathoracic malignancy. More rarely, metastatic lymph nodes are without primary site. Surgery is generally diagnostic, restricted to confirming the metastatic process, because of too numerous and disseminated or unresectable lymph nodes. Radical surgery consisting in lymphadenectomy can be effective in case of mediastinal lymph node malignancy without other extra- and intrathoracic disease. We observed in our experience and in several case reports long-term good results in such cases. We suggest that including surgery in the multimodality treatment of mediastinal metastatic lymph nodes may be advisable in selected patients.

Validation of a microRNA-based qRT-PCR test for accurate identification of tumor tissue origin

Identification of the tissue of origin of a tumor is vital to its management. Previous studies showed tissue-specific expression patterns of microRNA and suggested that microRNA profiling would be useful in addressing this diagnostic challenge. MicroRNAs are well preserved in formalin-fixed, paraffin-embedded (FFPE) samples, further supporting this approach. To develop a standardized assay for identification of the tissue origin of FFPE tumor samples, we used microarray data from 504 tumor samples to select a shortlist of 104 microRNA biomarker candidates. These 104 microRNAs were profiled by proprietary quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) on 356 FFPE tumor samples. A total of 48 microRNAs were chosen from this list of candidates and used to train a classifier. We developed a clinical test for the identification of the tumor tissue of origin based on a standardized protocol and defined the classification criteria. The test measures expression levels of 48 microRNAs by qRT-PCR, and predicts the tissue of origin among 25 possible classes, corresponding to 17 distinct tissues and organs. The biologically motivated classifier combines the predictions generated by a binary decision tree and K-nearest neighbors (KNN). The classifier was validated on an independent, blinded set of 204 FFPE tumor samples, including nearly 100 metastatic tumor samples. The test predictions correctly identified the reference diagnosis in 85% of the cases. In 66% of the cases the two algorithm predictions (tree and KNN) agreed on a single-tissue origin, which was identical to the reference diagnosis in 90% of cases. Thus, a qRT-PCR test based on the expression profile of 48 tissue-specific microRNAs allows accurate identification of the tumor tissue of origin.

Rare form of extraovarian peritoneal serous papillary carcinoma with solitary tumor in the abdominal wall: a case report and literature review

Cases of cancer presenting with microscopically confirmed metastatic malignancies for which no primary site can be detected are a challenge to stage clinically. Adenocarcinoma of unknown primary site is a subtype with high frequency that has no standard treatment and a poor prognosis. A 32-year-old female was found to have a tumor in the abdominal wall. Tumorectomy was conducted. A pathological examination indicated serous papillary adenocarcinoma, and peritoneal or ovarian cancer was suspected. Exploratory laparotomy and partial resection of the ovaries were carried out, but there were no malignant findings in the peritoneum, ovarian tissue or ascitic fluid. This is an extremely rare case of serous papillary adenocarcinoma with a cystic tumor that was categorized as extraovarian peritoneal serous papillary carcinoma (EPSPC) without other clinical findings.

Diagnosis of Metastatic Neoplasms: A Clinicopathologic and Morphologic Approach

Context.—The diagnosis of the site of origin of metastatic neoplasms often poses a challenge to practicing pathologists. A variety of immunohistochemical and molecular tests have been proposed for the identification of tumor site of origin, but these methods are no substitute for careful attention to the pathologic features of tumors and their correlation with imaging findings and other clinical data. The current trend in anatomic pathology is to overly rely on immunohistochemical and molecular tests to identify the site of origin of metastatic neoplasms, but this “shotgun approach” is often costly and can result in contradictory and even erroneous conclusions about the site of origin of a metastatic neoplasm.

Objective.—To describe the use of a systematic approach to the evaluation of metastatic neoplasms.

Data Sources.—Literature review and personal experience.

Conclusions.—A systematic approach can frequently help to narrow down differential diagnoses for a patient to a few likely tumor sites of origin that can be confirmed or excluded with the use of selected immunohistochemistry and/or molecular tests. This approach involves the qualitative evaluation of the “pretest and posttest probabilities” of various diagnoses before the immunohistochemical and molecular tests are ordered. Pretest probabilities are qualitatively estimated for each individual by taking into consideration the patient's age, sex, clinical history, imaging findings, and location of the metastases. This estimate is further narrowed by qualitatively evaluating, through careful observation of a variety of gross pathology and histopathologic features, the posttest probabilities of the most likely tumor sites of origin. Multiple examples of the use of this systematic approach for the evaluation of metastatic lesions are discussed.

[Isolated malignant mediastinal lymphadenopathy]

Mediastinal adenopathies without pulmonary disease may be benign, lymphomatous or the metastases from intra- or extrathoracic malignancy or more rarely metastases with unknown primary site. We observed 507 patients with isolated mediastinal adenopathies: benign, lymphomatous and metastatic disease represented 41.4% (210/507), 26.8% (136/507), 31.8% (161/507) of them, respectively. Management of the latter was the most challenging. Surgery was generally diagnostic, restricted to confirming the metastatic process, because of too numerous and disseminated or unresectable lymph nodes in 84% of patients (135/161). However, radical surgery consisting in lymphadenectomy proved effective in case of mediastinal lymph node malignancy without other extra- and intrathoracic disease. We observed long-term good results in such cases, which also was demonstrated by case reports in the literature. We suggest that including surgery in the multimodality treatment of mediastinal metastatic lymph nodes may be advisable in selected patients.

ISOLATE: a computational strategy for identifying the primary origin of cancers using high-throughput sequencing

Motivation: One of the most deadly cancer diagnoses is the carcinoma of unknown primary origin. Without the knowledge of the site of origin, treatment regimens are limited in their specificity and result in high mortality rates. Though supervised classification methods have been developed to predict the site of origin based on gene expression data, they require large numbers of previously classified tumors for training, in part because they do not account for sample heterogeneity, which limits their application to well-studied cancers.

Results: We present ISOLATE, a new statistical method that simultaneously predicts the primary site of origin of cancers and addresses sample heterogeneity, while taking advantage of new high-throughput sequencing technology that promises to bring higher accuracy and reproducibility to gene expression profiling experiments. ISOLATE makes predictions de novo, without having seen any training expression profiles of cancers with identified origin. Compared with previous methods, ISOLATE is able to predict the primary site of origin, de-convolve and remove the effect of sample heterogeneity and identify differentially expressed genes with higher accuracy, across both synthetic and clinical datasets. Methods such as ISOLATE are invaluable tools for clinicians faced with carcinomas of unknown primary origin.

Availability: ISOLATE is available for download at: http://morrislab.med.utoronto.ca/software

Contact:gerald.quon@utoronto.ca; quaid.morris@utoronto.ca

Supplementary information:Supplementary data are available at Bioinformatics online.

Differential diagnosis in immunohistochemistry with Bayes theorem

When immunohistochemical stains that are specific for specific tumor diagnoses do not yield diagnostic results, we often turn to less specific immunohistochemical stains and consider the resulting lists of possible tumor types. Typically, such lists are ordered according to tumor sensitivities for the stains. In probability terminology, sensitivity is the conditional probability of a positive stain given a specific tumor. Yet, the most useful probability to know is the probability of a specific tumor diagnosis, given a set of staining results. Bayes theorem provides this probability. To illustrate its use for differential diagnosis, I apply it here to the situation of carcinomas of uncertain primary site and use the information provided by stains for cytokeratin 7 and cytokeratin 20.

New prognostic index to predict survival in patients with cancer of unknown primary site with unfavourable prognosis

AIMS

To identify independent prognostic factors in patients with cancer of unknown primary site (CUP) who do not belong to prognostically favourable subsets, and to develop a prognostic index for predicting survival in these patients.

MATERIALS AND METHODS

In this prospective study, univariate and multivariate analyses of prognostic factors were conducted in a population of 145 patients with CUP in two clinical institutions. Subsets of patients with favourable prognostic features and those requiring well-defined treatment were excluded.

RESULTS

The 1-year overall survival rate for all patients was 42% and the median overall survival was 330 days. Overall survival was significantly related to the following pre-treatment prognostic factors: poor Eastern Cooperative Oncology Group performance status (ECOG PS)>or=2, presence of liver metastasis, elevated serum lactate dehydrogenase (LDH), high white blood cell count, anaemia, age>or=63 years, and prolonged QTc interval in electrocardiography (ECG). In multivariate analysis, four independent adverse prognostic parameters were retained: elevated LDH (hazard ratio 2.21; 95% confidence interval 1.41-3.47; P=0.001), prolonged QTc interval (hazard ratio 2.10; 95% confidence interval 1.28-3.44; P=0.003), liver metastasis (hazard ratio 1.77; 95% confidence interval 1.11-2.81; P=0.016) and ECOG PS>or=2 (hazard ratio 1.69; 95% confidence interval 1.05-2.73; P=0.03). We developed a prognostic index for overall survival based on the following subgroups: good prognosis (no or one adverse factor), intermediate prognosis (two adverse factors) and poor prognosis (three or four adverse factors). The median overall survival for the three subgroups was 420, 152 and 60 days, respectively, P<0.0001.

CONCLUSIONS

This study validated previously identified important prognostic factors for survival in patients with CUP. Prolonged QTc was additionally identified as a strong adverse prognostic factor. We developed a simple prognostic index using performance status, LDH, presence of liver metastasis and QTc interval in ECG, which allowed assignment of patients into three subgroups with divergent outcome.

Exploring the epidemiological characteristics of cancers of unknown primary site in an Australian population: implications for research and clinical care

OBJECTIVES

To investigate incidence, mortality and case survival trends for cancer of unknown primary site (CUP) and consider clinical implications.

METHOD

South Australian Cancer Registry data were used to calculate age-standardised incidence and mortality rates from 1977 to 2004. Disease-specific survivals, socio-demographic, histological and secular predictors of CUP, compared with cancers of known primary site, and of CUP histological types, using multivariable logistic regression were investigated.

RESULTS

Incidence and mortality rates increased approximately 60% between 1977--80 and 1981--84. Rates peaked in 1993--96. Male to female incidence and mortality rate ratios approximated 1.3:1. Incidence and mortality rates increased with age. The odds of unspecified histological type, compared with the more common adenocarcinomas, were higher for males than females, non-metropolitan residents, low socio-economic areas, and for 1977--88 than subsequent diagnostic periods. CUP represented a higher proportion of cancers in Indigenous patients. Case survival was 7% at 10 years from diagnosis. Factors predictive of lower case survival included older age, male sex, Indigenous status, lower socio-economic status, and unspecified histology type.

CONCLUSION

Results point to poor CUP outcomes, but with a modest improvement in survival. The study identifies socio-demographic groups at elevated risk of CUP and of worse treatment outcomes where increased research and clinical attention are required.

Role of fluorodeoxyglucose-PET versus fluorodeoxyglucose-PET/computed tomography in detection of unknown primary tumor: a meta-analysis of the literature

The objectives of this study were to evaluate the diagnostic accuracy of fluorodeoxyglucose (FDG)-PET and FDG-PET/computed tomography (CT) in the detection of primary tumors in patients presenting with carcinoma of unknown primary (CUP) unidentified by conventional workup, and to compare the statistical difference between the FDG-PET and FDG-PET/CT. Twenty-eight studies (involving a total of 910 patients) published between 1990 and 2007 were reviewed. These studies evaluated the role of FDG-PET and FDG-PET/CT in the detection of unknown primary tumors after physical examination and conventional workup failed to detect a primary tumor. Systematic methods were used to identify, select, and evaluate the methodological quality of the studies as well as to summarize the overall findings of sensitivity, specificity, and detection capacity of the primary tumor. The overall sensitivity and specificity of FDG-PET in detecting unknown primary tumors were 0.78 [95% confidence interval (CI): 0.72-0.84)] and 0.79 (95% CI: 0.74-0.83), respectively. Furthermore, FDG-PET detected 28.54% of tumors that were not apparent after CUP failed to be detected by conventional workup. Data were collected on the locations of primary tumors detected by FDG-PET in 17 studies and detected by FDG-PET/CT in seven studies. Tumors from the base of the tongue accounted for 20.7% (six of 29) of all false-positive FDG-PET scans, corresponding to a false-positive rate of 28.6% (six of 29), much higher than tumors from the others. FDG-PET exhibited a lower sensitivity with respect to the tumors at the base of the tongue and tonsils, which was 68.2 and 76.7%, respectively. In the eight studies with 430 patients diagnosed with CUP by FDG-PET/CT, 31.4% (n=135) of primary tumors were detected. The pooled sensitivity and specificity were 0.81 (95% CI: 0.74-0.87) and 0.83 (95% CI: 0.78-0.87), respectively. FDG-PET and FDG-PET/CT can detect primary tumors that went undetected by physical examination and conventional workup. FDG-PET exhibited lower sensitivity with respect to the tumors at the base of the tongue and the tonsils.

MicroRNAs accurately identify cancer tissue origin

MicroRNAs (miRNAs) belong to a class of noncoding, regulatory RNAs that is involved in oncogenesis and shows remarkable tissue specificity. Their potential for tumor classification suggests they may be used in identifying the tissue in which cancers of unknown primary origin arose, a major clinical problem. We measured miRNA expression levels in 400 paraffin-embedded and fresh-frozen samples from 22 different tumor tissues and metastases. We used miRNA microarray data of 253 samples to construct a transparent classifier based on 48 miRNAs. Two-thirds of samples were classified with high confidence, with accuracy >90%. In an independent blinded test-set of 83 samples, overall high-confidence accuracy reached 89%. Classification accuracy reached 100% for most tissue classes, including 131 metastatic samples. We further validated the utility of the miRNA biomarkers by quantitative RT-PCR using 65 additional blinded test samples. Our findings demonstrate the effectiveness of miRNAs as biomarkers for tracing the tissue of origin of cancers of unknown primary origin.

Patients' experiences of carcinoma of unknown primary site: dealing with uncertainty

It is generally acknowledged that patients may find it particularly hard to accept a cancer diagnosis if the primary origin cannot be identified. However, there is very little research exploring this.

AIMS

This is an exploratory mixed-method, largely qualitative, pilot study to explore patients' understanding of carcinoma of unknown primary site, any concerns they may have and to assess their quality of life.

METHODS

Ten patients were recruited and nine completed semi-structured interviews and McGill quality of life questionnaires. Thematic analysis was used in conjunction with demographic data and quality of life scores.

RESULTS

Six main themes were identified. These were--poor understanding, struggling with uncertainty/contrasting with stoical acceptance, undergoing multiple investigations, inability to treat, healthcare professionals not having the answers and difficulty explaining to others.

CONCLUSION

Many patients find the uncertainty difficult and would welcome more opportunity to ask questions and learn of others' experiences.