|Year : 2020 | Volume
| Issue : 4 | Page : 272-279
Trends, and tumor characteristics of lung cancer and malignant pleural mesothelioma in the East of Libya
Wail A Eldukali1, Khaled Elmahdi Omran2, Raouf Azzuz3
1 Gastroenterology and Hepatology Unit, Benghazi Medical Center, Benghazi, Libya
2 Oncology Department, Tobruk Medical Center, Tobruk, Libya
3 Department of Oncology, Benghazi Medical Center, Benghazi, Libya
|Date of Submission||22-Jun-2020|
|Date of Decision||31-Aug-2020|
|Date of Acceptance||13-Sep-2020|
|Date of Web Publication||04-Nov-2020|
Dr. Wail A Eldukali
Gastroenterology and Hepatology Unit, Benghazi Medical Center, Second Ring Road, Benghazi
Source of Support: None, Conflict of Interest: None
Background: Lung cancer is the most common cancer worldwide and the leading cancer killer. Lung cancer is classified histologically into two types; small-cell lung cancer and nonsmall-cell lung cancer (NSCLC) (squamous cell carcinoma, adenocarcinoma (AC), large cell carcinoma [LCC]). Malignant pleural mesothelioma is a rare thoracic tumor. We aimed to provide comprehensive epidemiological data about lung cancer in the eastern part of Libya. Patients and Methods: A retrospective medical records review of lung cancer patients attending the oncology department of Benghazi Medical Center from January 1, 2006 to December 31, 2015. Results: There were 684 lung cancer cases out of 7725 total registered cancer cases (8.85%), 627 were male (91.7%, median age 63.5), and 57 females (8.3%, median age 64). NSCLC was the dominant histology 78.5%, SCLC 11%, and malignant mesothelioma 2.5%. NSCLC subtypes were AC (35.1%), squamous carcinoma (25.7%), LCC (4.6%), and not otherwise specified (12.6%). Only 30.6% of cases were diagnosed in Libya, the most commonly used diagnostic modalities were bronchoscopic biopsy 46.6%, and computed tomography guided biopsy 17.4%. Only 18 cases were tested for epidermal growth factor receptor sensitizing mutations and anaplastic lymphoma kinase rearrangement fusion. Stage IV was the most common initial stage for NSCLC 60%, malignant mesothelioma 47.1%, and 74.7% of SCLC presented with extensive disease. Only 42.9% of males and 5.3% of female lung cancer patients were smokers. Conclusions: Lung cancer is a major health burden in Libya, and it is increasing in incidence; this epidemiological study tries to put this problem into public health and clinical perspective.
Keywords: Adenocarcinoma, asbestos, large cell carcinoma, lung cancer, malignant pleural mesothelioma, nonsmall-cell lung cancer, small-cell lung cancer, smoking, squamous cell carcinoma
|How to cite this article:|
Eldukali WA, Omran KE, Azzuz R. Trends, and tumor characteristics of lung cancer and malignant pleural mesothelioma in the East of Libya. Ibnosina J Med Biomed Sci 2020;12:272-9
|How to cite this URL:|
Eldukali WA, Omran KE, Azzuz R. Trends, and tumor characteristics of lung cancer and malignant pleural mesothelioma in the East of Libya. Ibnosina J Med Biomed Sci [serial online] 2020 [cited 2021 Apr 23];12:272-9. Available from: http://www.ijmbs.org/text.asp?2020/12/4/272/299528
| Introduction|| |
Lung cancer is the most common type of cancer worldwide. It represents 11.6% of cancer cases and leading cancer to kill.. It was estimated that 234,030 new lung cancer cases were diagnosed in the USA, and 83,550 estimated deaths in 2018. In Africa, lung cancer incidence was 7.3%, and the mortality rate was 5.8% of total cancer cases for both sexes. The world age-standardized ratio among men and women in northern Africa was 16.9 and 3.4/100,000, respectively, in 2018. There are no detailed data on lung cancers from Libya.
Lung cancer includes small-cell lung cancer (SCLC) and nonsmall cell lung cancer (NSCLC). NSCLC has four main histological types; squamous cell carcinoma (SQC), adenocarcinoma (AC), and large cell carcinoma (LCC). Malignant mesothelioma is a rare tumor from the mesothelial lining of pleural space, peritoneum, pericardium, and tunica vaginalis. The most common of which is the malignant pleural mesothelioma (MPM) representing 80%–90%., It is associated with asbestos exposure in 60%–70% as a causative agent. Smoking is implicated in >30% of all cancer deaths, and >80% of lung cancers in the Western world are associated with smoking. Smoking is linked to the histological subtype, where SCLC and SQC are thought to be caused mainly by smoking maybe they tend to develop in a main or segmental bronchus (central types) with the highest exposure where this relation is weaker in AC and LC (the peripheral type),,, preventing smoking and encourage smoking cessation decreases lung cancer burden. NSCLC is clinically staged to Stage I, II, III (Loco-regional), and IV (distant metastasis). SCLC is classified as either a limited or extensive disease.
Treatment of lung cancer requires a multidisciplinary team, including medical oncology, radiotherapy oncology, histopathologist, chest physician, thoracic surgery, radiologist, and others. Patients with lung cancer stage I, II, or III and localized MPM are generally treated with curative intent using surgery, chemotherapy, radiation therapy, or a combined modality approach. The management goals for patients with stage IV lung cancer and advanced MPM are to increase survival and maintain the quality of life for as long as possible while minimizing the side effects due to treatment.
The development of newer agents that target specific molecular pathways in malignant cells has resulted from a better understanding of the molecular pathways that drive malignancy in NSCLC. Therapy could be individualized based on the specific abnormality, if any, present in a given patient. These developments included the discovery of the genomic alterations of epidermal growth factor receptor (EGFR) gene mutation and anaplastic lymphoma kinase (ALK) gene fusion.,
Despite the notable advances in cancer diagnosis and treatment modalities, the overall 5-year survival for lung cancer remains poor compared to other types of cancer. Patients with MPM most commonly present at an advanced stage and the overall median survival in untreated patients is less than a year.,
This study aims to provide an epidemiological survey about lung cancer in the east of Libya and study the population's specific characteristics and the different disease patterns to effectively implement and direct the medical resources to improve patient care.
| Patients and Methods|| |
Design and settings
This is a retrospective medical records review of patients with lung cancer and MPM who were diagnosed between January 1, 2006, and December 31, 2015 and treated at the oncology department of Benghazi Medical Center (BMC). BMC is a tertiary medical center serving the eastern part of Libya inhabited by about two million people. The medical records were searched, and the study's records were retrieved. The collected data were de-identified for subsequent analysis. We included all patients who attended the oncology department older than 18 years with the complete medical records that identified them as lung cancer or mesothelioma from January 1, 2006 to December 31, 2015.
Lung cancer codes and definition: were made using the International Classification of Diseases, 10th revision, lung cancer code (C33-34) and mesothelioma C45, and the staging of lung cancer was according to the American Joint Committee on Cancer tumor node metastasis (TNM) system 8th edition.,
Statistical software SPSS package Version 22.0 (IBM SPSS Statistics for Windows, IBM Corp., Armonk, NY, USA) was used for descriptive analysis. The odds ratio with confidence intervals was calculated using multinomial logistic regression with a specified reference category using SPSS. Chi-square test of independence with Cramer's V (V) as a measure of effect size and the likelihood ratio was performed to examine the association among the categorical variables such as sex, smoking status, and the histopathology subtype.
| Results|| |
Lung cancer rates
In the period between 2006 and 2015, there were 7725 cancer cases, males were 3491 (45.2%) and females were 4234 (54.8%), of which there were 684 lung cancer cases. Lung cancer represented 8.9% of the total number of cancer cases, with an annual rate of 8.8%. There were 627 male cases out of 684 lung cancer cases (91.7%) and 57 female cases (8.3%), where the male to female ratio is about 9:1. The annual rate of lung cancer in men was17.9% of total male cancer cases, and for women was 1.3% of total female cancer cases. The demographic characteristics of patients and the annual trend of lung cancer rates are presented in [Table 1] and [Figure 1]. The median age of both sexes was 63.5 years, for men was 64, and for females, 60 years.
|Table 1: Demographic data, type of lung cancer, place of diagnosis, and diagnostic modality |
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|Figure 1: The annual trend for newly presenting patients to the clinic (2004--2015) and the distribution of ages of patients attending the clinic. (a) Annual Numbers of Lung Cancer Patients in in the Clinic. (b) Distribution of cases by age|
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Tunisia was the commonest place of diagnosis (46.6%) followed by Libya (30.6%). The most commonly used diagnostic modality, overall, was bronchoscopic biopsy (46.6%) followed by CT-guided biopsy (17.4%). The most frequently used diagnostic modalities in Libya were bronchoscopic biopsy (48.3%) and radiological diagnosis only (15.3%). The most common diagnostic modalities for MPM were pleural biopsy CT-guided biopsy and open biopsy [Table 1].
NSCLC was the most common diagnosis of lung cancer cases (78.5%), followed by SCLC (11.0%). In NSCLC, AC was the most common type, followed by SQC in both sexes (P = 0.075). There were 17 cases of MLP with a mean of age 67.8 years (standard deviation 7.7), representing 2.5% of total lung cancer cases, 15 were males (88%), and 2 were females (12%). The rest of the lung cancer type by sex are presented in [Table 2].
Genomic and molecular tests
Three hundred and fifteen out of 537 NSCLC patients presented with locally advanced or metastatic disease of NSCLC and were eligible for genomic and molecular testing. Only 18 cases had molecular testing; the majority were AC (14/18) and one each of LCC, SCLC, not otherwise specified (NOS). Overall, the actual molecular test results were mainly EGFR sensitizing mutation (8) followed by EGFR wild type (7) and one each of EGFR resistant mutation, ALK rearrangement, and combined EGFR and ALK mutation.
Staging and pattern of metastatic disease
Most of the staging was clinical (92.4%), and pathological staging was performed for only 7.6% of total cases. The most common initial stage for NSCLC cases was stage IV (60.33%), and for SCLC was extensive disease (74.66%). [Table 3] summarizes the initial stages of each cancer type. The majority of lung cancer cases were diagnosed late. Almost one fifth of all cases presented with multiple sites of metastasis at different sites, the bone came second as the most common single metastatic site. The spectrum of initial metastatic sites for the different histology types is presented in [Table 4].
Three hundred and ninety three out of 684 patients were with known smoking status (57.4%), 269 men and 57 women were current smokers. There was a significant relationship between sex and smoking habits (P < 0.00) and strong with Cramer's V effect size (0.54), where the smoking habit was dependent on the gender of the patient. The highest rate of smoking among the different histopathological types was noted in LCC, followed by SCLC, NOS, SQC, and the least was seen in AC class [Table 5].
| Discussion|| |
The eastern part of Libya covers the half surface area of Libya, and it is inhabited by 1.6 million people, who representing 28.3% of the population. The present study is a hospital registry-based analysis for lung cancer in BMC, which was the only cancer center in the eastern of Libya during the study period. We found that the annual burden of lung cancer cases was 8.9% of total cancer cases, with an annual rate of lung cancer for men was 17.9% and for women was 1.3%. In comparison with the national cancer registry of Eastern Libya NCREL (2003 and 2007), which was a population-based registry , the total rate of lung cancer of NCREL was higher at about 19%, and the rate in men was similar 18.9% and higher in women 8%. This difference may be explained by the fact that NCREL was made by 3 years of data, whereas our study spanned over 10 years. In Libya, lung cancer is the most common cancer in men, and in women, it is not in the top ten.. Our data showed that the male to female ratio was 9:1; however, NCREL was higher 14:1., If we compare that with lung cancer incidence in the neighboring countries such as Egypt, the lung cancer incidence rate for both sexes was 4.2% and for males 5.7% and for females 2.7%, whereas the total new lung cancer cases rates for Tunisia and Algeria were 13.3% and 8.0%, respectively, which were more or less comparable with our results., Globally, lung cancer is first in incidence (14.5%) and mortality among males and the third in incidence (8.4%) and second in mortality among females. this lower rate of lung cancer among Libyan females could be attributed to the lower rate of smoking.
In this study, NSCLC was the most common type of lung cancer, 78.5%, followed by SCLC 11.0%. However, data from the United States (2013–2017), NSCLC was the dominant subtype (84.3%) followed by SCLC (12.5%) of total lung cancer cases., In the present study, AC was the most common subtype for both sexes but relatively higher in women than other histopathological subtypes, similar to other international figures in the USA, Canada, and Japan. We also noticed that SQC and SCLC were higher in males than in females, which could be attributed to high smoking exposure rates in males. Moreover, the NOS subtype of NSCLC represented 12.6% of reported pathology in our study, which was relatively high in comparison to SEERS data, in which NOS represented 2.9% of NSCLC subtypes. It is crucial to identify the subtype of NSCLC histopathology as it predicts the prognosis and directs the type of therapy for each subtype. For example, anti-EGFR tyrosine kinase Inhibitors and anti-ALK therapy are working with AC, and anti-angiogenesis therapy is associated with bleeding in squamous pathology., Moreover, NOS subtype is associated with poor prognosis and aggressive behavior. Mesothelioma was more common in men aged >60 years (88%). Worldwide, the age-adjusted incidence ratio of MPM in 2011 was 4.9/million, the mean age at death was 70 years, and male to female was ratio 3.6:1. There was no data about asbestos exposure in the participants' file records.
Although smoking history was not recorded for all participants, from the available data, the rate of smoking in men was 42.9% and for women was 5.2%. These rates were similar to the latest WHO report on the global tobacco epidemic in 2019 showed that the prevalence of tobacco smoking in Libyan males (ages 25–64) is 49.6% and 0.7% in females. The Global Youth Tobacco Survey, 2010 reported that current tobacco product use among Libyan students aged between 13 and 15 was 12.4%. The prevalence of tobacco use in neighboring countries such as Egypt was in males 46.4% and 0.2% in females, and in Tunisia was 48.4% in males and 8.2% in females. The most common associated histopathological subtype with smoking was NOS, followed by SCLC, LCC, and SQC. These results are similar to the data from Italy.
Majority of the of lung cancer cases reported here (69.4%) were diagnosed abroad, reflecting the low accessibility and utilization of medical facilities and resources. For simple diagnostic procedures such as bronchoscopy, patients need to travel abroad to be diagnosed. Furthermore, we noticed the high rate of radiological diagnosis (15%) among those diagnosed in Libya compared to patients diagnosed abroad. Furthermore, we had a higher rate of unknown histology, and NOS histopathology (17.2% and 16.7% respectively) who were diagnosed in Libya, in comparison with Libyan patients diagnosed in Tunisia were (2.2% and 9.1%) and in Egypt (5.6% and 13.9%), respectively. This high NOS histology rate could be attributed to the lack of immunohistochemical staining and molecular markers locally.
Only a minority of our patients (18 cases; 5.7%) were subjected to molecular testing for EGFR gene mutation and ALK rearrangement gene fusion. This low rate of testing was due to the unavailability of testing locally. The need for the second biopsy, the patients' low-performance status, and the high cost of testing abroad, the targeted tyrosine kinases inhibitors to treat those patients with positive mutations were unavailable and expensive to afford. Therefore, the testing was impractical in that period of our study. This low rate of testing was also reported across academic and national cancer centers in the USA. In 2012, a survey of National Cancer Institute-designated cancer centers regarding biologic molecular testing for NSCLC; only 34% used upfront testing for the newly diagnosed patients, and 22% used a sequential protocol after the progression of lung cancer.
The majority of lung cancer cases are asymptomatic or presented with nonspecific symptoms at the earlier stages; hence the majority of lung cancer patients presented with locally advanced or metastatic disease, where the role of curable therapeutic interventions are only applicable to lung cancer patients presented at an early stage., The majority (86.2%) of NSCLC were diagnosed at late Stages (III and IV). Similarly, for SCLC patients, nearly three quarters were diagnosed as an extensive disease. About 70.6% of cases were diagnosed with late stages for MPM, and 10.7% for all lung cancer cases were unstaged/unknown. In the USA between the calendar year 2010–2016, 54% of all NSCLC lung cancer cases were with distant metastasis when diagnosed, 24% were regional, 20% were localized, and only 2% were unstaged/unknown , for SCLC 4% were localized, 20% were regional, 75% were distant, and 2% were unstaged/unknown.
In the present study, the most common metastatic sites for NSCLC were bone and brain. For SCLC, the lung was the most common metastasis, followed by the brain. These are widely different from larger previous reports., A previous population-based study involving 21,169 patients, the most frequent metastatic sites were the nervous system, bone, liver, respiratory, and adrenal gland. Furthermore, another large study of 1994 patients, the most frequent metastatic sites were lung, bone, brain, liver, and adrenals.
The quality of medical records and the absence of national central electronic medical records are apparent limitations of the present study. Many patients diagnosed elsewhere have not provided adequate information about the diagnostic workup, staging, and pathology reports. Besides, insufficiency and shortage of local diagnostic investigations such as immunohistochemistry and molecular testing hindered further classifications and patients' management. These limitations had made some gaps in this study's results
| Conclusions|| |
Lung cancer in Libya represents a significant health issue in primary prevention, screening, diagnosis, and therapy costs. A central national cancer registry center is essential and must be done promptly to enable researchers to study and assess the current burden of cancer in Libya for future planning and directing the best strategies to tackle this significant health problem. Any primary prevention intervention should include tobacco control initiative at the governmental level. This type of epidemiological study helps put this problem into perspective for better use of already limited resources to provide the best care for cancer patients. Future studies about epidemiology, therapy, and survival of cancer are much needed in this area of the world.
The authors would like to thank all doctors, nurses, and clerks of the oncology department of BMC, Benghazi, Libya, for their support in data collection during the study.
The authors jointly conceived and conducted the study jointly. Wail A. Eldukali analyzed the data and drafted the manuscript. Other authors reviewed the manuscript for intellectual content, and all authors approved its final version.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
Compliance with ethical principles
The Research Ethics Board of Benghazi Medical Center approved the study (Ref 2017-22-44-1). All patients attending the institution sign a general consent form allowing their de-identified data for quality assurance and research. All data were analyzed and reported anonymously.
| References|| |
Bray F, Ferlay J, Soerjomataram I, Siegel RL, Torre LA, Jemal A. Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin 2018;68:394-424.
Siegel RL, Miller KD, Jemal A. Cancer statistics, 2018. CA Cancer J Clin 2018;68:7-30.
Meza R, Meernik C, Jeon J, Cote ML. Lung cancer incidence trends by gender, race and histology in the United States, 1973-2010. PLoS One 2015;10:e0121323.
Price B, Ware A. Time trend of mesothelioma incidence in the United States and projection of future cases: an update based on SEER data for 1973 through 2005. Crit Rev Toxicol 2009;39:576-88.
Robinson BM. Malignant pleural mesothelioma: an epidemiological perspective. Ann Cardiothorac Surg 2012;1:491-6.
McDonald JC, McDonald AD. The epidemiology of mesothelioma in historical context. Eur Respir J 1996;9:1932-42.
Centers for Disease Control and Prevention (CDC). Smoking-attributable mortality, years of potential life lost, and productivity losses-United States, 2000-2004. MMWR Morb Mortal Wkly Rep 2008;57:1226-8.
Kenfield SA, Wei EK, Stampfer MJ, Rosner BA, Colditz GA. Comparison of aspects of smoking among the four histological types of lung cancer. Tob Control 2008;17:198-204.
Amin MB, Greene FL, Edge SB, Compton CC, Gershenwald JE, Brookland RK, et al
. The eighth edition AJCC cancer staging manual: continuing to build a bridge from a population-based to a more “personalized” approach to cancer staging. CA Cancer J Clin 2017;67:93-9.
Howington JA, Blum MG, Chang AC, Balekian AA, Murthy SC. Treatment of stage I and II non-small cell lung cancer: Diagnosis and management of lung cancer, 3rd
ed.: American College of Chest Physicians evidence-based clinical practice guidelines. Chest 2013;143:e278S-e313S.
Birring SS, Peake MD. Symptoms and the early diagnosis of lung cancer. Thorax 2005;60:268-9.
Gutierrez ME, Choi K, Lanman RB, Licitra EJ, Skrzypczak SM, Pe Benito R, et al
. Genomic profiling of advanced non-small cell lung cancer in community settings: Gaps and opportunities. Clin Lung Cancer 2017;18:651-9.
Weiss JM, Stinchcombe TE. Second-line therapy for advanced NSCLC. Oncologist 2013;18:947-53.
Kwak EL, Bang YJ, Camidge DR, Shaw AT, Solomon B, Maki RG, et al
. Anaplastic lymphoma kinase inhibition in non-small-cell lung cancer. N Engl J Med 2010;363:1693-703.
Lindeman NI, Cagle PT, Beasley MB, Chitale DA, Dacic S, Giaccone G, et al
. Molecular testing guideline for selection of lung cancer patients for EGFR and ALK tyrosine kinase inhibitors: guideline from the College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology. J Thorac Oncol 2013;8:823-59.
Spiro SG, Silvestri GA. One hundred years of lung cancer. Am J Respir Crit Care Med 2005;172:523-9.
Howlader N, Noone AM, Krapcho M, Garshell J, Miller D, Altekruse SF, et al
. SEER Cancer Statistics Review, 1975-2011, Based on November 2013 SEER data Submission, Posted to the SEER Website, April 2014. Bethesda, MD: National Cancer Institute; 2014.
Milano MT, Zhang H. Malignant pleural mesothelioma: A population-based study of survival. J Thorac Oncol 2010;5:1841-8.
World Health Organization. International Statistical Classification of Diseases and Related Health Problems 10th
Revision (ICD-10)-WHO Version for 2016. World Health Organization; 2016.
Bureau of Stastics and Census. Statsitical Book 2012. Available from: http://bsc.ly/?P=0
. [Last accessed on 2020 Jun 01].
El Mistiri M, Salati M, Marcheselli L, Attia A, Habil S, Alhomri F, et al
. Cancer incidence, mortality, and survival in Eastern Libya: Updated report from the Benghazi cancer registry. Ann Epidemiol 2015;25:564-8.
El Mistiri M, Verdecchia A, Rashid I, El Sahli N, El Mangush M, Federico M. Cancer incidence in eastern Libya: the first report from the Benghazi Cancer Registry, 2003. Int J Cancer 2007;120:392-7.
Ibrahim AS, Khaled HM, Mikhail NNH, Baraka H, Kamel H. Cancer Incidence in Egypt: Results of the National Population-Based Cancer Registry Program. J Cancer Epidemiol Prev 2014;2014:437971.
Jazieh AR, Algwaiz G, Errihani H, Elghissassi I, Mula-Hussain L, Bawazir AA, et al
. Lung cancer in the middle East and North Africa Region. J Thorac Oncol 2019;14:1884-91.
Youlden DR, Cramb SM, Baade PD. The international epidemiology of lung cancer: Geographical distribution and secular trends. J Thorac Oncol 2008;3:819-31.
Howlader N, Noone AM, Krapcho M, Miller D, Brest A, Yu M, et al
., editors. SEER Cancer Statistics Review, 1975-2017, National Cancer Institute. Bethesda, MD, based on November 2019 SEER data submission, posted to the SEER web site, April 2020.
Barta JA, Powell CA, Wisnivesky JP. Global epidemiology of lung cancer. Ann Glob Health 2019;85(1):8.
Mok TS, Wu YL, Thongprasert S, Yang CH, Chu DT, Saijo N, et al
. Gefitinib or carboplatin-paclitaxel in pulmonary adenocarcinoma. N Engl J Med 2009;361:947-57.
Tane S, Nishio W, Ogawa H, Hokka D, Tane K, Tanaka Y, et al
. Clinical significance of the 'not otherwise specified' subtype in candidates for resectable non-small cell lung cancer. Oncol Lett 2014;8:1017-24.
Ou SH, Zell JA. Carcinoma NOS is a common histologic diagnosis and is increasing in proportion among non-small cell lung cancer histologies. J Thorac Oncol 2009;4:1202-11.
Delgermaa V, Takahashi K, Park EK, Le GV, Hara T, Sorahan T. Global mesothelioma deaths reported to the World Health Organization between 1994 and 2008. Bull World Health Organ 2011;89:716-24, 724A-724C.
Barbone F, Bovenzi M, Cavallieri F, Stanta G. Cigarette smoking and histologic type of lung cancer in men. Chest 1997;112:1474-9.
Schink JC, Trosman JR, Weldon CB, Siziopikou KP, Tsongalis GJ, Rademaker AW, et al
. Biomarker testing for breast, lung, and gastroesophageal cancers at NCI designated cancer centers. J Natl Cancer Inst 2014;106:dju256.
Riihimäki M, Hemminki A, Fallah M, Thomsen H, Sundquist K, Sundquist J, et al
. Metastatic sites and survival in lung cancer. Lung cancer (Amsterdam, Netherlands) 2014;86:78-84.
Oikawa A, Takahashi H, Ishikawa H, Kurishima K, Kagohashi K, Satoh H. Application of conditional probability analysis to distant metastases from lung cancer. Oncol Lett 2012;3:629-34.
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]