Determining the site of the primary cancer in patients with skeletal metastasis of unknown origin: a retrospective study

Bone Tumor Risk Stratification and Management System: A Consensus Guideline from the ACR Bone Reporting and Data System Committee

The assessment and subsequent management of a potentially neoplastic bone lesion seen at diagnostic radiography is often complicated by diagnostic uncertainty and inconsistent management recommendations. Appropriate clinical management should be directed by risk of malignancy. Herein, the ACR-sponsored Bone Reporting and Data System (Bone-RADS) Committee, consisting of academic leaders in the fields of musculoskeletal oncology imaging and orthopedic oncology, presents the novel Bone-RADS scoring system to aid in risk assignment and provide risk-aligned management suggestions. When viewed in the proper clinical context, a newly identified bone lesion can be risk stratified as having very low, low, intermediate, or high risk of malignancy. Radiographic features predictive of risk are reviewed include margination, pattern of periosteal reaction, depth of endosteal erosion, pathological fracture, and extra-osseous soft tissue mass. Other radiographic features predictive of histopathology are also briefly discussed. To apply the Bone-RADS scoring system to a potentially neoplastic bone lesion, radiographic features predictive of risk are each given a point value. Point values are summed to yield a point total, which can be translated to a Bone-RADS score (1-4) with corresponding risk assignment (very low, low, intermediate, high). For each score, evidence-based and best practice consensus management suggestions are outlined. Examples of each Bone-RADS scores are presented, and a standardized diagnostic radiography report template is provided.

Effective examination methods for identifying the primary origins of metastatic bone tumors of unknown primary origin during the initial visit: A retrospective chart review study

Objective:

To provide appropriate treatment for patients, early diagnosis of the primary origin of skeletal metastases of unknown primary origin is important. This study aimed to assess the examination strategy effective for identifying the primary origin of skeletal metastases of unknown primary origin.

Methods:

Sixty-one patients with skeletal metastases of unknown primary origin were reviewed. The primary origin was examined via physical examination, blood test including tumor markers, chest radiography, thoracoabdominal computed tomography scan, positron emission tomography–computed tomography scan, metastatic lesion biopsy, and other assessments. Examination methods considered effective for the diagnosis of the primary origin in a specific type of cancer were investigated.

Results:

The lung was the most common primary origin site, followed by the lymph nodes, prostate, and breast. Meanwhile, biopsy was the most effective examination, followed by positron emission tomography–computed tomography scan and thoracoabdominal computed tomography scan. Blood tests are useful for detecting hematological malignancies and prostate cancer. Computed tomography scans can be used to identify cancers in the lung, breast, and kidney, which are the common primary origins. Forty-one (67.2%) of the 61 patients with skeletal metastases of unknown primary origin were diagnosed via the first four steps, that is, physical examination, blood test, chest radiography, and thoracoabdominal computed tomography scan. Finally, two patients were diagnosed with skeletal metastases of unknown primary origin.

Conclusion:

The examination steps used in this study, including physical examination, blood test including tumor markers, chest radiography, thoracoabdominal computed tomography scan, positron emission tomography–computed tomography scan, biopsy, and other assessments were effective in determining the primary origin of skeletal metastases of unknown primary origin during the initial visit.

The Surgical Management of Proximal Femoral Metastases: A Narrative Review

The proximal femur is a common location for the development of bony metastatic disease. Metastatic bone disease in this location can cause debilitating pain, pathologic fractures, reduced quality of life, anemia or hypercalcemia. A thorough history, physical examination and preoperative investigations are required to ensure accurate diagnosis and prognosis. The goals of surgical management is to provide pain relief and return to function with a construct that provides stability to allow for immediate weightbearing. Current surgical treatment options include intramedullary nailing, hemiarthroplasty or total hip arthroplasty and endoprosthetic reconstructions. Oligometastatic renal cell carcinoma must be given special consideration as tumor resection and reconstruction has survival benefit. Both tumor and patient characteristics must be taken into account before deciding on the appropriate surgical intervention.

UNKNOWN PRIMARY TUMOR SITES IN SPINAL METASTASIS

ABSTRACT Objective: The goal of the study was to report the prevalence of spinal metastasis with unknown primary tumor, clinical features, treatment results and patient survival. Methods: A retrospective evaluation of 103 patients with spinal metastasis and epidural compression, who underwent surgical treatment between March 2009 and August 2015. The prevalence of metastatic spinal tumor with unknown primary tumor was evaluated, as well clinical features, survival and treatment results. Results: Of 103 patients with spinal metastasis and epidural compression, seven patients (6.8%) with unknown primary tumor site were identified; five (71.4%) male and two (28.6%) female, with ages ranging from 37 to 67 years (50.7 years). The metastasis was located in the thoracic spine in six of the patients (85.7%) and in the cervical spine in one (14.3%). The mean survival time was 44.8 days. Conclusion: Spinal metastasis with unknown primary tumor was found in 6.8% of patients. The prognosis and outcomes were poor, and patients had poor survival rates. Level of evidence III; Experimental study.

Features of Spinal Metastases: A Retrospective View

BACKROUND

The present study aimed to determine the frequency of spinal metastases, to evaluate the features of spinal metastases, and to reveal clues to shed light on the origin of spinal metastases with unknown primary.

METHODS

The data of patients who were followed up with the diagnosis of cancer in Istanbul Oncology Hospital between 2017 and 2019 were analyzed retrospectively. A total of 156 patients with spinal metastases and without visceral metastases were included in the study by applying inclusion and exclusion criteria. Clinical data, pathological diagnostic reports, and positron emission tomography-computed tomography results of 156 patients were evaluated. The groups were evaluated in terms of age, gender, number of spinal metastases (single focus, multiple focus), and localization of spinal metastasis. The spinal localization evaluation included both the main anatomical localizations and a detailed evaluation of each spine.

RESULTS

The most common metastasis region was the thoracic spine in respiratory system cancers (28.38%), the thoracic + lumbar spine in breast (42.42%), prostate (50.00%), and gynecologic (40.00%) cancers, and the lumbar spine in gastrointestinal (37.50%) and urinary (30.00%) tract cancers (P = .313). C5 spinal metastasis percentages were significantly higher in breast and gastrointestinal tract cancers than the others (P = .042). T5 spinal metastasis percentage was significantly higher in gynecologic tumors than in the other cancers (P = .002). T10 spinal metastasis percentages were significantly higher in prostate and gynecologic tumors than the others (P = .016). L1 spinal metastasis percentage was significantly higher in breast tumors (P = .009). L2 spinal metastasis percentages were significantly higher in breast, prostate, and gynecologic tumors (P = .011). L4 spinal metastasis percentages were significantly higher in breast and prostate tumors (P = .041). L5 spinal metastasis percentage was significantly higher in prostate tumors (P = .029) than the other cancers.

CONCLUSIONS

It was observed that primary cancers were often prone to metastasis to nearby spine. The results obtained by detailed examination of spinal metastases may provide a clinical benefit by providing clues in investigation of primary unknown cancers.

LEVEL OF EVIDENCE

3.

The frequency of occult solid malignancy in patients with polymyalgia rheumatica-like symptoms

Aims:

We aim to evaluate the clinical usefulness of systematic screening for occult cancer in patients with polymyalgia rheumatic (PMR)-like symptoms in real-life practice.

Methods:

All patients seen by rheumatologists in Burgundy, France, between March 2016 and December 2018 for new-onset PMR that met the 2012 ACR/EULAR classification criteria were prospectively included. Patients underwent systematic screening including determination of the erythrocyte sedimentation rate, serum C-reactive protein levels, thoracic, abdominal and pelvic computed tomography (CT-TAP) and, in men, serum prostate-specific antigen. The standardized incidence ratio (SIR) for cancers was calculated using 2012 national estimates of cancer incidence. Potential predictive factors for the diagnosis of cancer were then evaluated using univariate and multivariate analyses.

Results:

Among the 118 patients included, nine cases of cancer were confirmed and diagnosed with CT-TAP: kidney carcinoma (n = 4), lung cancer (n = 2), pancreatic, colon, and ampullary carcinoma (n = 1 each). Among these cancers, five were localized (four kidney, and one ampullary carcinoma) and were treated with complete surgical resection. The expected incidence of cancer in the general population was 1.95, leading to an overall SIR of 4.6 (95% CI 2.4–8.9, p < 0.0001). An additional analysis was performed for the kidney carcinoma, and it showed a highly significant increase in SIR: 80.8 (95% CI 30.3–215.4). In 80% of patients, the PMR-like syndrome regressed during cancer treatment. No other predictive factors for cancer were found.

Conclusion:

Systematic screening for cancer including CT-TAP in real-life practice revealed occult solid malignancy, mostly early-stage cancer, in a relevant proportion of patients presenting PMR-like symptoms. The high proportion of kidney cancer (40%) is worth highlighting, especially considering that it is not one of the most frequent cancers after 50 years of age.

Does PET/CT Aid in Detecting Primary Carcinoma in Patients with Skeletal Metastases of Unknown Primary?

BACKGROUND

Patients older than 40 years presenting with osteolytic bone lesions are likely to have a diagnosis of carcinoma, even if they had no prior cancer diagnosis. For patients with no prior cancer diagnosis, there is a well-accepted algorithm to determine a potential primary site. That algorithm, however, leaves approximately 15% of people without a detectable primary tumor site, making treatment decisions extremely difficult. Positron emission tomography (PET) fused with CT, more commonly known as PET/CT, has emerged as an important staging modality for many other malignancies but has been used in a very limited fashion in musculoskeletal oncology.

QUESTIONS/PURPOSES

We asked (1) What is the ability of PET/CT to detect the source of the primary tumor in patients with a skeletal metastasis of unknown primary? (2) How does PET/CT perform in detecting metastases in other sites in patients with a skeletal metastasis of unknown primary?

METHODS

A retrospective analysis between 2006 and 2016 of the pathology database of a single tertiary center identified 35 patients with a biopsy-proven skeletal metastasis (histologically confirmed carcinoma or adenocarcinoma) and a PET/CT scan that was performed after the standard diagnostic evaluation of the primary cancer site. Patients were identified through use of our pathology database to identify all biopsy-proven bone carcinomas. This was then cross referenced with our imaging database to identify all patients who were at any time evaluated with PET/CT. During this time, we identified 1075 patients with biopsy-proven metastatic bone disease through our pathology database. Any indication for a PET/CT was included, and was most often done for staging of the identified malignancy or evaluation for the unknown source. Data regarding the ability of PET/CT to find or confirm the primary cancer and all metastatic sites were evaluated. The standard diagnostic evaluation (history and physical, laboratory evaluation, CT of the chest/abdomen/pelvis and whole body bone scan) identified the primary cancer in 22 of the 35 patients. Among the 35 patients, there were a total of 176 metastatic sites of disease identified, with 115 identified with the standard diagnostic evaluation (before PET/CT).

RESULTS

Among patients with a skeletal metastasis of unknown primary, PET/CT was unable to identify the primary cancer in 12 of 13 patients. PET/CT confirmed the site of the known primary cancer in all 22 patients. There were 176 total metastatic sites. Of the 115 metastases known before PET/CT, PET/CT failed to identify three of 115 (3% false-negative rate).

CONCLUSIONS

PET/CT may not provide any additional benefit over the standard evaluation for identification of the primary cancer in patients with a skeletal metastasis of unknown primary, although it may have efficacy as a screening tool equivalent or superior to the standard diagnostic algorithm for evaluation of the overall metastatic burden in these patients.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Clinical Impact of F-18 FDG PET-CT on Biopsy Site Selection in Patients with Suspected Bone Metastasis of Unknown Primary Site

Purpose

We investigated the clinical role of F-18 fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) in the identification of the primary site and the selection of the optimal biopsy site in patients with suspected bone metastasis of unknown primary site.

Methods

The patients with suspected bone metastasis who underwent PET-CT for evaluation of primary site were enrolled in this study. The primary sites were identified by the histopathologic or imaging studies and were classified according to the FDG uptake positivity of the primary site. To evaluate the guiding capability of PET-CT in biopsy site selection, we statistically analyzed whether the biopsy site could be affected according to the presence of extra-skeletal FDG uptake.

Results

Among 74 enrolled patients, 51 patients had a metastatic bone disease. The primary site was identified in 48 of 51 patients (94.1%). Forty-six patients were eligible to test the association of clinical choice of biopsy site with PET positivity of extra-skeletal lesion. The extra-skeletal biopsies were done in 42 out of 43 patients with positive extra-skeletal uptake lesions. Bone biopsies were inevitably performed in the other three patients without extra-skeletal uptake lesions. The association came out to be significant (Fisher's exact test, P < 0.001).

Conclusion

F-18 FDG PET-CT significantly contributed not only to identify the primary site but also to suggest optimal biopsy sites in patients with suspected bone metastasis.

Cervical bone pain revealing a bone metastatic colon cancer: A case report

Colorectal cancer (CRC) is one of the most common malignancies worldwide, with common sites of metastases including abdominal lymph nodes, the liver and lungs. Bone metastases are known to be relatively rare sites of metastasis. The present study reported a patient with advanced colorectal cancer and metastatic colorectal cancer (mCRC) with atypical metastases presentation. Bone mCRCs were not frequent and presented a poor prognosis in the present case. It was concluded that further studies are required to clarify the pathogenesis of bone metastases, to improve the management and treatment of patients.

Role of 18F-FDG PET/CT in the detection of primary malignancy in patients with bone metastasis of unknown origin

OBJECTIVE

The present study investigates the role of ¹⁸F-FDG PET/CT in the detection of primary malignancy in patients with bone metastasis of unknown primary origin (BMUO).

MATERIAL AND METHODS

This retrospective study considered histopathological examination findings or clinical follow-up data as the standard reference in the diagnosis of primary tumors, and results were compared with results of PET/CT scans.

RESULTS

The study included 100 patients with BMUO (74 males, 26 females, mean age 61 years). The primary origin was identified in 92 of the 100 patients. Adenocarcinoma was the most common histopathological subtype in patients in whom the primary origin of tumor was detected (65.2%). The most common primary tumor was lung carcinoma (n=52) followed by prostate (n=13), breast (n=7), colon (n=4), gastric (n=3), ovarian (n=2), renal cell (n=2), adrenal (n=1), thyroid (n=1), endometrial (n=1) and parotid (n=1) carcinoma, hepatobiliary cancers (n=2), leiomyosarcoma (n=2) and maxillary sinus tumor (n=1). The numbers of patients in whom PET/CT showed true positive, true negative, false positive (FP) and false negative (FN) results were 72, 7, 8 and 13, respectively. The sensitivity, specificity, accuracy and detection rate of PET/CT in detecting the primary tumor were 84.7%, 46%, 79% and 72%, respectively. The overall survival was significantly lower in lung cancer group when compared to non-lung cancer group, whereas it was significantly higher in prostate cancer group than in non-prostate cancer group.

CONCLUSIONS

PET/CT, as a non-invasive method, can be preferred as the first choice in the detection of primary tumor in patients with BMUO.

Skeletal Metastases of Unknown Primary: Biological Landscape and Clinical Overview

Skeletal metastases of unknown primary (SMUP) represent a clinical challenge in dealing with patients diagnosed with bone metastases. Management of these patients has improved significantly in the past few years. however, it is fraught with a lack of evidence. While some patients have achieved impressive gains, a more systematic and tailored treatment is required. Nevertheless, in real-life practice, the outlook at the beginning of treatment for SMUP is decidedly somber. An incomplete translational relevance of pathological and clinical data on the mortality and morbidity rate has had unsatisfactory consequences for SMUP patients and their physicians. We examined several approaches to confront the available evidence; three key points emerged. The characterization of the SMUP biological profile is essential to driving clinical decisions by integrating genetic and molecular profiles into a multi-step diagnostic work-up. Nonetheless, a pragmatic investigation plan and therapy of SMUP cannot follow a single template; it must be adapted to different pathophysiological dynamics and coordinated with efforts of a systematic algorithm and high-quality data derived from statistically powered clinical trials. The discussion in this review points out that greater efforts are required to face the unmet needs present in SMUP patients in oncology.

Spinal Cord Injury From Spinal Tumors: Prevalence, Management, and Outcomes

BACKGROUND

With the aging population in the United States, it can be anticipated that the prevalence of spinal cord injuries (SCIs) and cancer will increase. Primary or metastatic spine tumors sit at a unique intersection of these 2 realms. Our objective was to evaluate the prevalence, outcomes, and complications after the management of SCI arising from spinal tumors.

METHODS

In the present retrospective evaluation, all patients with SCI and a diagnosis of primary or metastatic spinal cancer who had been admitted to the inpatient rehabilitation unit at a level 1 trauma center from January 2003 to January 2014 were evaluated. The demographic data (age, sex, race/ethnicity), tumor characteristics, American Spinal Injury Association score, and complications were evaluated.

RESULTS

A total of 757 SCI entries were identified, and 685 unique patients met our inclusion criteria. Of those, 81 had SCIs due to spinal tumors (11.8% of all SCIs and 19.2% of nontraumatic SCIs). Most tumors were located in the thoracic region (65.4%) and were primary central nervous system in origin (21.0%), including meningioma (7.4%), schwannoma (3.7%), and ependymoma (2.5%). The next most common origins of the spinal tumors were metastases from the lung (17.3%), prostate (9.9%), kidney (8.6%), lymphoma (7.4%), and multiple myeloma (7.4%). Of these patients, 76.5% underwent surgical management, with a complications rate of 61.3%. The overall mortality rate at the latest follow-up examination was 63.0%.

CONCLUSIONS

SCI associated with spinal tumor is often managed surgically and associated with high rates of complications. The present study has demonstrated longer survival rates compared with the existing data.

Prognostic and risk factors in patients with metastatic bone disease of an upper extremity

Background

The aim of this study was to evaluate survival of metastatic bone disease of an upper extremity, and to identify the prognostic factors that influence survival.

Methods

Patients with metastatic bone disease of an upper extremity between 2008 and 2015 were reviewed from the database of a tertiary university hospital.

Results

Of 102 patients, 48 males and 54 females with a median age of 61 (range, 28–82 years), the humerus (64.7%), clavicle (13.7%), and scapula (12.7%) were the common sites for bone metastasis of an upper extremity. Fifty-nine (57.8%) presented with pathologic fracture. No history of cancer was found in 76.5% of patients. The mean onset of metastatic bone disease after the first diagnosis of primary cancer was 4.74 ± 14.07 months (range, 0–84 months). Lung (31.4%) was the most common primary cancer followed by liver (14.7%), breast (12.7%), thyroid (7.8%), and renal (3.9%). Eighty-two cases (80.39%) died from the disease such that the median survival was 4.08 months (95% CI 2.57–6.17). The significant risk factors were the type of primary tumor (P < 0.001, HR = 4.44; 95% CI, 1.99–9.90) and ECOG performance status (P = 0.021, HR = 2.11, 95% CI 1.12–3.99).

Conclusions

Patients with metastatic bone disease of an upper extremity have a limited life expectancy. The type of primary tumor and ECOG performance status were the important prognostic factors that influenced overall survival. Our data help in the management of patients, families, and doctors, so as to avoid over- or under-treatment.

Role of 18F-FDG PET/CT in patients without known primary malignancy with skeletal lesions suspicious for cancer metastasis

BACKGROUND

When subjects without a known malignancy present with suspicious skeletal lesions, differential diagnosis and primary cancer identification is important. Here, we investigated the role of FDG PET/CT in this clinical situation.

METHODS

We enrolled 103 patients with no known malignancies who were referred for FDG PET/CT because of bone lesions that were suspicious for cancer metastasis. Each extra-skeletal FDG lesion was categorized as consistent with primary cancer or with metastasis based on the distribution and pattern of all abnormal lesions in the individual.

RESULTS

Final diagnosis revealed that bone lesions represented cancer metastasis in 75 patients (72.8%). In the remaining 28 patients (27.2%), they were from other causes including multiple myeloma or lymphoma, malignant primary bone tumor, and benign bone disease. PET/CT indicated a primary cancer in 70 patients (68.0%). This was the correct primary site in 46 cases and the incorrect site in 13 cases (including 6 cases with cancer of unknown primary, CUP). In the remaining 11 cases, the bone lesions were due to other causes. PET/CT did not indicate a primary cancer in 33 patients (32.0%). Of these cases, 17 did not have a primary cancer, 8 had CUP, and 8 had primary cancers that were missed. Thus, PET/CT had a sensitivity of 61.3% and specificity of 60.7% for primary cancer identification in the entire population. Excluding patients with CUP, PET/CT sensitivity was 75.4%. PET/CT also provided information useful for recognizing multiple myeloma and benign bone disease as the cause of the skeletal lesions.

CONCLUSIONS

In patients without known malignancies with suspected skeletal cancer metastasis, FDG PET/CT can help identify the primary cancer and provide useful information for differential diagnosis.

Use of minimally invasive spine surgical instruments for the treatment of bone tumors

INTRODUCTION

Orthopedic oncologists often encounter patients with minor bony lesions that are difficult to access surgically and therefore require large exposures out of proportion to the severity of disease that confer significant patient morbidity. Minimally invasive surgical techniques offer the advantage of smaller incisions, shorter operative times, decreased tissue damage, and decreased costs. A variety of surgical procedures have emerged using minimally invasive technologies, particularly in the field of spine surgery. Areas covered: In this article, we describe the Minimal Exposure Tubular Retractor (METRx^TM) System which is a minimally invasive surgical device that utilizes a series of dilators to permit access to a surgical site of interest. This system was developed for use in treatment of disc herniation, spinal stenosis, posterior lumbar interbody fusion, transforaminal lumbar interbody fusion and spinal cord stimulation implantation. We also describe novel uses of this system for minimally invasive biopsy and treatment of benign and metastatic bone lesions at our institution. Expert commentary: Minimally invasive surgical techniques will continue to expand into the field of orthopedic oncology. With a greater number of studies proving the safety and effectiveness of this technique, the demand for minimally invasive treatments will grow.

Surgery for metastatic spine tumors in the elderly. Advanced age is not a contraindication to surgery!

BACKGROUND

With recent advances in oncologic treatments, there has been an increase in patient survival rates and concurrently an increase in the number of incidence of symptomatic spinal metastases. Because elderly patients are a substantial part of the oncology population, their types of treatment as well as the possible impact their treatment will have on healthcare resources need to be further examined.

PURPOSE

We studied whether age has a significant influence on quality of life and survival in surgical interventions for spinal metastases.

STUDY DESIGN

We used data from a multicenter prospective study by the Global Spine Tumor Study Group (GSTSG). This GSTSG study involved 1,266 patients who were admitted for surgical treatments of symptomatic spinal metastases at 22 spinal centers from different countries and followed up for 2 years after surgery.

PATIENT SAMPLE

There were 1,266 patients recruited between March 2001 and October 2014.

OUTCOME MEASURES

Patient demographics were collected along with outcome measures, including European Quality of Life-5 Dimensions (EQ-5D), neurologic functions, complications, and survival rates.

METHODS

We realized a multicenter prospective study of 1,266 patients admitted for surgical treatment of symptomatic spinal metastases. They were divided and studied into three different age groups: <70, 70-80, and >80 years.

RESULTS

Despite a lack of statistical difference in American Society of Anesthesiologists (ASA) score, Frankel neurologic score, or Karnofsky functional score at presentation, patients >80 years were more likely to undergo emergency surgery and palliative procedures compared with younger patients. Postoperative complications were more common in the oldest age group (33.3% in the >80, 23.9% in the 70-80, and 17.9% for patients <70 years, p=.004). EQ-5D improved in all groups, but survival expectancy was significantly longer in patients <70 years old (p=.02). Furthermore, neurologic recovery after surgery was lower in patients >80 years old.

CONCLUSIONS

Surgeons should not be biased against operating elderly patients. Although survival rates and neurologic improvements in the elderly patients are lower than for younger patients, operating the elderly is compounded by the fact that they undergo more emergency and palliative procedures, despite good ASA scores and functional status. Age in itself should not be a determinant of whether to operate or not, and operations should not be avoided in the elderly when indicated.

Current orthopaedic management of bony metastases in the proximal third of the femur

Patients presenting with skeletal metastatic lesions requiring surgery are increasing, this is due to an ageing population and improved oncological survival following advances in medical management. Furthermore, patients are living longer with skeletal metastatic disease. The majority of bone metastases occur in the proximal femur. Robust diagnosis (Biopsy) and treatment is required to ensure that patients can mobilise fully weight bearing immediately post-surgery and that the construct should outlive the patients expected survival. We review the changing management of metastatic disease in the proximal femur.

Skeletal Metastasis of Unknown Primary Origin at the Initial Visit: A Retrospective Analysis of 286 Cases

Background

Skeletal metastasis is a common metastatic event for several carcinomas, and the treatment for skeletal metastasis of unknown primary (SMUP) are a critical issue in cancer therapy. Making a diagnosis of the primary site is the most crucial step in the treatment of SMUP; however, the procedures are sometimes difficult and time-consuming, and the primary site often remains unknown. Therefore, to establish optimal diagnostic strategies and elucidate the overall survival rates of SMUP, we conducted this retrospective study.

Methods

We retrospectively analyzed the clinical data for 286 SMUP cases from a total of 2,641 patients with skeletal metastases who were treated between 2002 and 2014 at our initiations.

Results

The primary sites were identified in 254/286 patients (88.8%), while 32 (11.2%) primary sites were not detected by our diagnostic strategies. Lung cancer was identified in 72 (25.2%) cases, and was the most frequently observed primary lesion. The median survival time of the SMUP patients was 20.0 months, while the median survival times of solitary bone metastasis cases and multi-bone metastasis cases were 39.0 months and 16.0 months, respectively. The median survival times of prostate cancer cases was over 120 months, that of patients with primary lung cancers was 9.0 months and the median survival time of cases who were finally diagnosed with an unknown primary was 11.0 months.

Conclusions

We believe that our study would contribute to establishing an optimal strategy for diagnosing the primary site in SMUP patients, and our data provide definite indications for the survival times for different SMUP situations.

Bone metastases of unknown origin: epidemiology and principles of management

Metastases are the most common malignancies involving bone; breast, prostate, lung and thyroid are the main sites of primary cancer. However, up to 30 % of patients present with bone metastases of unknown origin, where the site of the primary neoplasm cannot be identified at the time of diagnosis despite a thorough history, physical examination, appropriate laboratory testing and modern imaging technology (CT, MRI, PET). Sometimes only extensive histopathological investigations on bone specimens from biopsy can suggest the primary malignancy. At other times, a bone lesion can have such a highly undifferentiated histological appearance that a precise pathological classification on routine hematoxylin-eosin-stained section is not possible. The authors reviewed the relevant literature in an attempt to investigate the epidemiology of the histological primaries finally identified in patients with bone metastases from occult cancer, and a strategy of management and treatment of bone metastases from occult carcinomas is suggested. Lung, liver, pancreas and gastrointestinal tract are common sites for primary occult tumors. Adenocarcinoma is the main histological type, accounting for 70 % of all cases, while undifferentiated cancer accounts for 20 %. Over the past 30 years, lung cancer is the main causative occult primary for bone metastases and has a poor prognosis with an average survival of 4-8 months. Most relevant literature focuses on the need for standardized diagnostic workup, as surgery for bone lesions should be aggressive only when they are solitary and/or the occult primaries have a good prognosis; in these cases, identification of the primary tumor may be important and warrants special diagnostic efforts. However, in most cases, the primary site remains unknown, even after autopsy. Thus, orthopedic surgery has a mainly palliative role in preventing or stabilizing pathological fractures, relieving pain and facilitating the care of the patient in an attempt to provide the most appropriate therapy for the primary tumor as soon as possible.

LEVEL OF EVIDENCE

5.

FDG-PET images of acrometastases

Skeletal metastasis is common in patients with malignancy, but very few patients have acrometastasis, that is, metastasis to the hand or foot. We present 2 cases of acrometastasis from lung cancer where primary and metastatic foci were demonstrated on FDG-PET. The first case involves a 53-year-old man who complained of left foot pain and had osteolytic metastasis in the left calcaneus due to lung adenocarcinoma. True whole-body PET demonstrated lung cancer with calcaneal metastasis. Another case involves a 62-year-old man with large cell carcinoma of the right lung who complained of right wrist pain. Osteolytic metastasis of the hamate was demonstrated on images.

Metastatic bone tumors: Analysis of factors affecting prognosis and efficacy of CT and 18F-FDG PET-CT in identifying primary lesions

We analyzed the prognostic factors in patients with metastatic bone tumors and evaluated the efficacy of different modalities in identifying the primary lesions. A total of 145 patients with bone metastases who attended the orthopaedic outpatient clinic were included in this study. The most frequent site of bone metastases was the spine. The primary tumor type was differently distributed between patients with a known primary tumor at the first visit and those with an unknown primary lesion. The number of breast cancer cases was statistically significantly lower in the primary-unknown group. However, the number of myeloma cases was significantly higher in the primary-unknown group. Survival was significantly lower in the skeletal-related events (SREs) compared to that in the non-SREs group. Furthermore, survival was significantly worse in patients with a performance status (PS) of ≥2 compared to those with a PS of ≤1 and neurological complications occurred statistically more often in the group with worse PS (≥2). Survival rates were significantly lower in the non-spinal compared to those in the spinal metastatic group. Since the majority of breast cancer patients presented with metastasis in the spine, a breast cancer origin was a positive prognostic factor in patients with spinal metastases. Although there were no significant differences between computed tomography (CT) and ¹⁸F-fluoro-2-deoxyglucose (¹⁸F-FDG) positron emission tomography (PET)-CT in detecting primary lesions, CT may be the first choice due to its feasibility. In conclusion, lung cancer, SREs and worse PS were adverse prognostic factors for patients with bone metastasis. In addition, CT scans may be more useful for determining the primary lesion of a bone metastasis compared to ¹⁸F-FDG PET-CT in a timelier manner.

Non-spine bone metastasis as an initial manifestation of cancer in Korea

Non-spine bone metastasis accounts for approximately 20% of all skeletal metastases, but little data have been published that focused on bone metastasis to the pelvis and extremities as an initial manifestation of cancer. We determined 1) clinicopathologic characteristics of patients who presented with non-spine bone metastasis of unknown primary malignancy, and 2) process by which the diagnosis of primary cancer was made. We retrospectively reviewed 84 patients with bone metastasis of unknown primary cancer site at the time of presentation. The study population consisted of 56 men and 28 women, with a mean age of 59.1 yr (17.5-85.6 yr). The average follow-up period was 20.8 months (1-120 mo). Primary cancer site was identified in 79 patients (94.0%), and was determined to be the lung (46.4%), kidney (13.1%), liver (9.5%), thyroid (8.3%), and prostate (4.8%). Five-year overall survival rate was 28.0%. Multiple bone metastases, distant organ metastasis, and multiple bone with organ metastases were the significant prognostic factors in univariate analysis. Multiple bone metastases remained significant after multivariate analysis (P = 0.008). Lung cancer is the most common site of primary cancer, and patients with multiple bone metastases have a poor prognosis, possibly due to disseminated cancer and a greater tumor burden.

Imaging findings of solitary spinal bony lesions and the differential diagnosis of benign and malignant lesions

OBJECTIVE

The purpose of this study was to present the MRI and CT findings of solitary spinal bone lesions (SSBLs) with the aims of aiding the differential diagnoses of malignant tumors and benign lesions, and proposing a diagnostic strategy for obscure SSBLs.

METHODS

The authors retrospectively reviewed the imaging findings of 19 patients with an obscure SSBL on MRI at our hospital from January 1994 to April 2011. The 19 patients were divided to benign groups and malignant groups according to final diagnosis. MRI and CT findings were evaluated and the results of additional work-up studies were conducted to achieve a differential diagnosis.

RESULTS

At final diagnoses, 10 (52.6%) of the 19 SSBLs were malignant tumors and 9 (47.4%) were benign lesions. The malignant tumors included 6 metastatic cancers, 3 multiple myelomas, and 1 chordoma, and the benign lesions included 4 osteomyelitis, 2 hemangiomas, 2 nonspecific chronic inflammations, and 1 giant cell tumor. No MRI characteristics examined was found to be significantly different in the benign and malignant groups. Reactive sclerotic change was observed by CT in 1 (10.0%) of the 10 malignant lesions and in 7 (77.8%) of the 9 benign lesions (p=0.005).

CONCLUSION

Approximately half of the obscure SSBLs were malignant tumors. CT and MRI findings in combination may aid the differential diagnosis of obscure SSBLs. In particular, sclerotic change on CT images was an important finding implying benign lesion. Finally, we suggest a possible diagnostic strategy for obscure SSBLs on MRI.

Atypical neurofibroma and osteosclerotic metastasis

35-year-old male presented with multiple swellings in left leg, headache, weakness of limbs for 4 months, and blurring of vision for the last 15 days. On examination, he was pale, cachexic with generalized lymphadenopathy and lower motor neuron type weakness of limbs sparing right upper limb. Blood investigations showed anemia with high alkaline phosphatase. Chest radiograph revealed osteosclerotic metastatic lesion in humerus. Biopsy of leg lesion revealed atypical neurofibroma. Computed tomography (CT) of thorax revealed osteoblastic metastasis. Bone marrow aspiration showed cells with round to oval nuclei, fine granular chromatin with large central prominent nucleoli and eosinophilic cytoplasm with acini formation. Magnetic resonance imaging (MRI) of brain and spinal cord defined metastatic leptomeningeal deposits. Cerebrospinal fluid (CSF) cytology was positive for malignant cells. Gastroscopy showed an ulceroinfiltrative growth from stomach which on histopathology revealed diffuse adenocarcinoma. Palliative treatment was given with intrathecal methotrexate and systemic corticosteroid with chemotherapy. Patient's symptom improved drastically, but we lost him to followup.

Surgical management of unknown primary tumors metastatic to the spine

OBJECT

Patients presenting with spinal metastases from unknown primary tumors (UPTs) are rare. The authors reviewed their surgical experience to evaluate outcomes and identify predictors of survival in these patients.

METHODS

This study is a retrospective analysis of patients undergoing surgery for metastatic spine disease from UPTs between June 1993 and February 2007 at The University of Texas M. D. Anderson Cancer Center.

RESULTS

Fifty-one patients undergoing 52 surgical procedures were identified. The median age at spine surgery was 60 years. The median survival from time of diagnosis was 15.8 months (95% CI 8.1-23.6) and it was 8.1 months (95% CI 1.6-14.7) from time of spine surgery. Postoperative neurological function (Frankel score) was the same or improved in 94% of patients. At presentation, 77% had extraspinal disease, which was associated with poorer survival (6.4 vs 18.1 months; p = 0.041). Multiple sites (vs a single site) of spine disease did not impact survival (12.7 vs 8.7 months; p = 0.50). Patients with noncervical spinal disease survived longer than those with cervical disease (11.8 vs 6.4 months, respectively; p = 0.029). Complete versus incomplete resection at index surgery had no impact on survival duration (p > 0.5) or local recurrence (p = 1.0). Identification of a primary cancer was achieved in 31% of patients.

CONCLUSIONS

This is the first reported surgical series of patients with an unknown source of spinal metastases. The authors found that multiple sites of spinal disease did not influence survival; however, the presence of extraspinal disease had a negative impact. The extent of resection had no effect on survival duration or local recurrence. With an overall median survival of 8.1 months following surgery, aggressive evaluation and treatment of patients with metastatic disease of the spine from an unknown primary source is warranted.

FNAB of metastatic lesions with special reference to clinicopathological analysis of primary site in cases of epithelial and non-epithelial tumors

AIMS

To ascertain the cytological diagnosis of metastatic lesions with special reference to the clinicopathological analysis of the primary site in cases of epithelial and non-epithelial tumors.

MATERIALS AND METHODS

One hundred seventy-one suspected metastatic lesions were aspirated with a 22-23G needle and the smears were fixed and stained. The cases in which the primary site was not evident at the time of initial presentation were subsequently subjected to thorough physical examination followed by radiological investigations for the search of the primary site. Histopathological examination was performed in 16 cases with inconclusive cytological impression.

OBSERVATIONS

Of the total cases of metastatic lesions, 155 cases (90.6%) were diagnosed by fine needle aspiration biopsy and 16 cases (9.4%) by histopathology. The majority of the cases, 81 (47.4%), were observed in the fifth decade of life, followed by 76 cases (44.4%) in the sixth decade and 11 cases (6.4%) in the seventh decade of life. Lymph nodes were the most frequent site of metastasis in 115 cases (67.3%), with the majority in the cervical group. The oropharynx, including the oral cavity and pharyngolarynx, was observed to be the most common primary site, 55 cases (32.2%).

CONCLUSION

The most critical aspect of the evaluation of metastatic cases is the accurate pathologic assessment of the malignant tissues in conjunction with pertinent clinical data. Such close collaboration between the clinician and the pathologist may maximize the diagnostic potential in treatable primary tumors.

Surgical treatment of bone metastases in patients with lung cancer

Lung cancer is the leading cause of cancer mortality. Bone metastases are a common complication in lung cancer. The therapeutic approach and the type of surgical treatment of these lesions have not been clearly defined. Outcome and prognosis of patients with bony metastases and a variety of surgical interventions were analysed retrospectively. In 58 patients we performed 62 surgeries. The most common locations of metastases were the spine (32 patients), the proximal femur (10) and the pelvis (11). Twenty-one patients had a singular and 20 had multiple osseous lesions; 17 showed additional visceral involvement. Nine patients had a local progression of their disease and 49 a systemic progression. Patients with local progression (n = 9) had a better prognosis than the patients with systemic progression (p = 0.0083). Fracture (p = 0.0017) worsened prognosis, whereas the number of bone lesions or the presence of a visceral lesion did not. Patients with small lesions showed a better survival than patients with large lesions (p = 0.02). Ten percent of the patients died within 30 days and 78% within one year after surgery. Fracture of bone due to metastatic lung cancer worsens the prognosis whereas the number of bone lesions, the presence of a visceral lesion and the surgical approach do not.

Role of 2-deoxy-2-[F-18] fluoro-D-glucose positron emission tomography in the management of bone and soft-tissue metastases

We retrospectively reviewed 71 histopathologically-confirmed bone and soft-tissue metastases of unknown origin at presentation. In order to identify the site of the primary tumour all 71 cases were examined with conventional procedures, including CT, serum tumour markers, a plain radiograph, ultrasound examination and endoscopic examinations, and 24 of the 71 cases underwent 2-deoxy-2-[F-18] fluoro-D-glucose positron emission tomography (FDG-PET). This detected multiple bone metastases in nine patients and the primary site in 12 of the 24 cases; conventional studies revealed 16 primary tumours. There was no significant difference in sensitivity between FDG-PET and conventional studies. The mean maximal standardised uptake value of the metastatic tumours was significantly higher than that of the primary tumours, which is likely to explain why FDG-PET did not provide better results. It was not superior to conventional procedures in the search for the primary site of bone and soft-tissue metastases; however, it seemed to be useful in the staging of malignancy.

Diagnosis of a previously unidentified primary site in patients with spinal metastasis: diagnostic usefulness of laboratory analysis, CT scanning and CT-guided biopsy

When the primary site is unknown in patients with spinal metastases, there can be problems in locating the site of tumor origin. Most previous reports on metastases of unknown origin have not been limited to the spine. The purpose of this study is to assess the usefulness of laboratory analysis, chest, abdominal and pelvic CT and CT-guided biopsy in patients with spinal metastases of unknown origin (SMUO). A retrospective review of the clinical histories of 27 patients with SMUO was done. A total of 43 patients with SMUO were seen at our institution between 2002 and 2007. Of the 43 patients, 27 who underwent all 3 tests (laboratory analysis including M protein and tumor markers, chest, abdominal and pelvic CT and CT-guided biopsy) were included in this study. We retrospectively assessed the diagnostic usefulness of those 3 tests in the 27 patients. In 27 patients, the final diagnosis was obtained in 26 patients. Myeloma was the most common malignancy followed by lung carcinoma. M protein was positive in all 7 patients with myeloma and negative in patients with other malignancies. The level of tumor markers was elevated in 16 of 17 patients with a solid tumor and in all 3 with lymphoma. CA15-3 was elevated in 4 of 27 patients, CA19-9 in 5 of 27 patients, CA125 in 2 of 27 patients, CEA in 6 of 27 patients, SCC in 2 of 27 patients, NSE in 7 of 27 patients, AFP in 1 of 27 patients, PIVKA-II in 1 of 27 patients, TPA in 6 of 27 patients, IAP in 3 of 12 patients, thyroglobulin in 2 of 27 patients, sIL-2R in 3 of 24 patients, and PSA in 5 of 17 male patients. Myeloma, lymphoma and prostate carcinoma had a marker with high sensitivity and specificity (M protein, sIL-2R and PSA). Eleven primary tumor sites (40.7%) were detected (6 lung, 1 prostate, 1 kidney, 1 thyroid, 1 liver, and 1 pancreas) by chest, abdominal and CT scanning. Biopsy led to determination of the final diagnosis in 12 (44.4%) of 27 patients (5 myelomas, 3 lymphomas, 2 prostate carcinomas, 1 renal-cell carcinoma, 1 thyroid carcinoma). In the remaining 15 patients, biopsy did not lead to determination of the final diagnosis, because the histological diagnosis was either an adenocarcinoma or an undifferentiated carcinoma, the tissue sample was not diagnostic. A laboratory analysis limited to specific tumor markers such as PSA and protein electrophoresis is considered to be useful in making a final diagnosis. Chest, abdominal and pelvic CT is considered to be useful for making a final diagnosis in solid tumors, but not for hematologic tumors. A CT-guided biopsy had a low determination rate in the final diagnosis in comparison to a laboratory analysis and CT scanning for solid tumors and it is not considered to be essential for the diagnosis of hematologic tumors.

Diagnosis and staging of spine tumors

Persistent axial pain with or without neurologic changes should prompt workup for a possible tumor of the spine. Metastatic disease is more predominant than primary tumors, but still needs adequate evaluation before any management. The various steps of evaluation, diagnosis, and staging are reviewed.

Algorithms and planning in metastatic spine tumors

Metastatic spine tumors cause the loss of the supporting function of the spine through vertebral destruction or invade and compress the spinal cord or cauda equine. As a result, metastatic spine tumor causes severe pain, paralysis, or impairment of activities of daily living (ADL). Also, because the finding of metastatic foci in the spine suggests a generalized disorder, life expectancy and treatment options have many limitations. For this reason, treatment is primarily symptomatic, and the major goals in selecting therapeutic modalities are to relieve pain, prevent paralysis, and improve ADL. This article discusses the selection of treatment for metastatic spine tumors and, in particular, the indications for surgical treatment.

Les carcinomes de primitif inconnu

PURPOSE

Carcinoma of unknown primary site is a common clinical syndrome, accounting for 2% of cancer patients. Diagnosis is a recurrent challenge for internists. Treatment is difficult and prognosis is still poor. This review presents one synthesis of diagnosis strategies and therapeutic trials. It envisages the interest of new molecular biology methods as well as therapeutic perspectives.

CURRENT KNOWLEDGE AND KEY POINTS

Pathologic examination completed with immunohistochemical tests, and, depending on cases, with electron microscopy, cytogenetics, and molecular biology is a key-point for diagnosis. Diagnosis work-up, based on histological type and on individualization of some clinical presentation, proceeds in three steps. Positron emission tomography is recommended when a curative treatment is planed, particularly in cases of isolated metastasis. Functional status analysed using the performance status and simple biologic parameters (serum lactate dehydrogenase, serum alkaline phosphatase) permit us to assess prognosis. Chemotherapy is offered for patients with a good general health status.

FUTURE PROSPECTS AND PROJECTS

Further evaluation of positron emission tomography, as well as cost-benefit analyses, is warranted. Further randomised trials are necessary to determine the optimal chemotherapy regimen in good-risk patients and the interest of chemotherapy in patients with poor-risk disease. Gene expression profiling and proteomic evaluation, as well as pharmacogenomic offer new investigation fields.

Serum tumor markers in skeletal metastasis

BACKGROUND

There have been no well-documented reports detailing the relationship between skeletal metastasis and tumor markers in a large series of patients. The purpose of our study was to assess the relationship between the clinical features of skeletal metastasis and serum tumor markers and to determine whether tumor markers are a useful modality in the differential diagnosis of skeletal metastasis.

METHODS

We retrospectively reviewed consecutive 458 patients with skeletal metastasis and divided the patients into two groups according to six clinical presenting factors. We assessed whether these groups influenced the level of the tumor markers in univariate and multivariate analysis.

RESULTS

Patients with skeletal metastasis of carcinoma had a higher level of markers CEA (P < 0.0001) and CA19-9 (P = 0.0008) than patients with primary bone tumors and hematological malignancies. Univariate analysis of clinical variables revealed that metastasis on axial skeleton, multiple skeletal metastases and visceral metastasis were associated with the serum CEA and CA19-9 levels. By multivariate analysis, metastasis on axial skeleton, multiple skeletal metastases and visceral metastasis were found to be associated with the serum CEA and CA19-9 levels. At least one of the tumor markers was elevated in 73% of all patients.

CONCLUSIONS

The higher tumor marker level (CEA, CA19-9) is predictive of metastasis on the axial skeleton, multiple skeletal metastases and visceral metastasis. Tumor markers are useful as a screening test to distinguish skeletal metastases of carcinoma from primary bone tumors or hematological malignancy from primary bone tumor and hematological malignancy.

Bone metastases revealing primary tumors. Comparison of two series separated by 30 years

OBJECTIVE

To compare two series of patients admitted to a rheumatology department for bone metastases 30 years apart and to obtain a pragmatic estimation of the percentage of bone metastases revealing cancer.

METHODS

The recent series was composed of 132 patients seen between 1989 and 1996 and the earlier series of 50 patients admitted between 1958 and 1967. All patients were admitted to the same rheumatology department for bone metastases from a diagnosed or undiagnosed primary. Both series were studied retrospectively. The rate of occurrence of each cancer diagnosis was determined in the patients with and without known primaries.

RESULTS

Among the patients with metastatic disease as the first manifestation of cancer, the percentage with lung cancer increased from the early to the recent series, particularly among women, whereas the percentages with prostate and breast cancer decreased. The primary remained unknown in 27% and 38% of patients in the early and recent series, respectively.

CONCLUSION

Despite the introduction of new investigations, our ability to identify primaries responsible for bone metastases does not seem to have improved. However, our data should be interpreted with caution since recruitment probably differed between the two series.

The clinical relevance of cytokeratin phenotyping in needle biopsy of liver metastasis

Although cytokeratin (CK) phenotyping of metastatic tumors is now routine in many laboratories, the clinical relevance of the procedure has seldom been addressed. We carried out a prospective clinical study of 134 consecutive cases of metastatic adenocarcinoma of the liver diagnosed by needle biopsies stained routinely for CK20 and CK7. The most probable localization of the primary tumor, deduced from this staining pattern, was stated in the original pathology report. The present study compared this assignment with the information available at the time of interpretation of the liver biopsy, to the results of the subsequent clinical investigation, and to the officially reported cause of death as outcome. As expected, the primary tumors were localized in the colon or in the rectum in 85% (34/40) of the CK20+/CK7- metastases. The definite diagnosis remained metastatic colorectal carcinoma in 83% (15/18) of the cases with diagnosed colorectal cancer before the liver biopsy. In the cases without a known primary tumor when the liver biopsy was interpreted, primary colorectal localization was accurately predicted in 86% (19/22) of the patients. Compared to the outcome, 77% (36/47) of the CK20+/CK7+ metastases had the expected pancreaticobiliary primary localization in 83% (30/36) without any primary tumor being known at the time of interpretation of the liver biopsy. In contrast, the majority of CK20- metastatic carcinomas had an unexpected primary localization, 50% (16/32) in the CK20-/CK7+ and 60% (9/15) in the CK20-/CK7- subgroup. In addition, the origin of the liver metastasis remained unknown in 37% (12/32) of CK20-/CK7+ cases. Thus, the CK20+/CK7- phenotype indicates a colorectal origin of the liver metastasis with considerable accuracy and independently of the available clinical information. The same is true for CK20+/CK7+ metastases, which indicate primary tumor localization in the pancreas or in the biliary tree. The results in the CK20- subgroups of the liver metastases are disappointing and cannot substantially help the clinical investigation.

Cytogenetic profile of unknown primary tumors: clues for their pathogenesis and clinical management

Unknown primary tumors (UPTs) represent an entity of great clinical and biological interest, whose origin cannot be determined even after medical workup. To better understand their pathogenesis by outlining their genetic composition, 20 UPTs were investigated by G-banding, supplemented with Fluorescence In Situ Hybridization and Comparative Genomic Hybridization analyses. The data obtained were sufficient to reach a diagnosis in five cases-four lymphomas and one Ewing sarcoma-demonstrating that in a subset of UPTs, cytogenetics can be an adjunct for differential diagnosis. In the remaining 15 UPTs, an aggressive cytogenetic pattern was revealed. The most frequently rearranged chromosome regions were 1q21, 3p13, 6q15-23, 7q22, 11p12-5, and 11q14-24, pinpointing gene loci probably associated with the peculiar pathogenesis of UPTs. The preferential involvement of 4q31, 6q15, 10q25, and 13q22 in adenocarcinomas (whereas 11q22 is involved in the rest of the carcinomas)-in addition to the marked divergence in the mean average of chromosomal changes, 16 and 3, respectively-demonstrates genotypic differences between the two histologic subgroups. Furthermore, the significantly shorter survival in cases displaying massive chromosome changes compared with those having a few changes indicates that the cytogenetic pattern might be used as a tool to assess prognosis in UPTs, even without the detection of their primary site.

Indications for operative treatment

The importance of careful assessment of clinical, biomedical, and radiographic factors in the indications for operative treatment are stressed in this article. The indication for surgical resection of solitary lesions versus simple stabilization are compared and contrasted. The biologic behavior of various types of tumors is emphasized.