Incidence Of Bronchogenic Carcinoma Research Articles

Human Cytomegalovirus (CMV) Infection Associated With Decreased Risk of Bronchogenic Carcinoma: Understanding How a Previous CMV Infection Leads to an Enhanced Immune Response Against Malignancy.

​Cytomegalovirus (CMV) causes a long-lasting, asymptomatic infection that reportedly has both advantageous and deleterious effects on tumor progression. The purpose of this study was to evaluate the correlation between CMV infection and the incidence of bronchogenic carcinoma. The study was conducted using a Health Insurance Portability and Accountability Act (HIPAA)compliant national database to identify patients both with and without histories of CMV infectionusing International Classification of Diseases (ICD-10 and ICD-9) codes. Access to the database was granted by Holy CrossHealth, Fort Lauderdale for the purpose of academic research with standard statistical methods used to analyze the data. 14,319 patients were included in both the control and CMV-exposed groups and matched by age range and Charlson Comorbidity Index (CCI) scores. The incidence of bronchogenic carcinomawas 1.69% (243/14,319 patients) in the CMV group and 6.08% (871/14,319 patients)in the control group. The difference was statistically significant bya p-value of less than 2.6x10-16 with anodds ratio of 0.26 (95% CI: 0.24-0.30). The two groups were also matched for treatment. Further evaluation of the CMV-specific treatment effects on outcomes was limited due to the insufficient number of treated patients in the control group. This study found a statistically significant correlation between a prior CMV infection and a reduced incidence of bronchogenic carcinoma. This study demonstrates the need for further investigation into how the tumor microenvironment and host immune system are altered by the presence of a latent CMV infection.

Detection of synchronous lung tumors in patients presenting with squamous cell carcinoma of the head and neck

Screening for synchronous pulmonary tumors in patients presenting with squamous cell carcinoma of the head and neck (SCCHN) is important, because detection may alter subsequent management. We conducted a retrospective review, comparing effectiveness of pulmonary screening using thoracic CT or chest X-ray, in 1882 patients presenting with SCCHN. The overall rate of synchronous pulmonary tumors was 4.3%. The number needed to scan, ie, the number of thoracic CTs required to detect 1 pulmonary tumor, is reported for recurrent primary tumors, primary disease load (T and N classification), and individual primary sites. The incidence of pulmonary metastases is related to locoregional disease load while the incidence of bronchogenic carcinoma is sporadic. Although it is possible to propose a pragmatic screening protocol for pulmonary metastases, this is not possible for bronchogenic carcinomas. Therefore, we recommend that thoracic CT is used in all cases to screen for coexistent pulmonary pathology.

Carcinoma broncogénico en pacientes con trasplante de órgano sólido. Papel de la cirugía

Background The incidence of neoplastic diseases is higher in patients undergoing solid organ transplant. However, the incidence of bronchogenic carcinoma (BC) is controversial. The objective of our study was to determine the incidence of BC in a large cohort of transplant patients and the role of surgery. Material and methods Until December 2006, 3596 patients underwent solid organ transplant at our institution; 24 (0.7%) patients subsequently developed BC, of which 6 (24%) were classified as clinical stage I and submitted to surgical treatment. Survival was estimated by the Kaplan-Meier method. Results Three patients received a liver transplant, two a kidney transplant and one a heart transplant. All were male and all had a smoking history. Mean age was 58.6 years. Two patients had cough, one accompanied by bloody expectoration, and BC was an incidental finding in the remaining cases. The interval between transplant and diagnosis of BC was 38.1 months. Epidermoid carcinoma was the most frequent histological type. Mean tumour size was 3.6 cm (range, 1.3–6). One tumour was classified as pathological stage IA, four as stage IB and one as IIB due to parietal pleural invasion. No patient died during the perioperative period and only one had a haemothorax which resolved with chest tube drainage. Mean hospital stay was 8.5 days (range, 7–11). The immunosuppression regimen was maintained continuously. In subsequent follow-up, one patient died from BC metastasis, one from sepsis, one from chronic renal failure, and three remained alive. The probability of survival at 5 years was 40%, and median survival was established at 5 years. Conclusions The incidence of BC in patients undergoing solid organ transplant and the proportion of patients diagnosed in early stages does not differ from non-transplant patients diagnosed with BC, which questions the role of immunosuppression in the genesis and aggressiveness of BC in transplant patients. Surgery may offer acceptable results in early stages, with acceptable rates of perioperative morbidity and mortality.

Bronchogenic carcinoma in patients undergoing solid organ transplant. The role of surgery

BackgroundThe incidence of neoplastic diseases is higher in patients undergoing solid organ transplant. However, the incidence of bronchogenic carcinoma (BC) is controversial. The objective of our study was to determine the incidence of BC in a large cohort of transplant patients and the role of surgery. Material and methodsUntil December 2006, 3596 patients underwent solid organ transplant at our institution; 24 (0.7%) patients subsequently developed BC, of which 6 (24%) were classified as clinical stage I and submitted to surgical treatment. Survival was estimated by the Kaplan-Meier method. ResultsThree patients received a liver transplant, 2 a kidney transplant and 1 a heart transplant. All were male and all had a smoking history. Mean age was 58.6 years. Two patients had cough, one accompanied by bloody expectoration, and BC was an incidental finding in the remaining cases. The interval between transplant and diagnosis of BC was 38.1 months. Epidermoid carcinoma was the most frequent histological type. Mean tumour size was 3.6cm (range, 1.3–6). One tumour was classified as pathological stage IA, 4 as stage IB, and 1 as IIB due to parietal pleural invasion. No patient died during the perioperative period and only one had a haemothorax which resolved with chest tube drainage. Mean hospital stay was 8.5 days (range, 7–11). The immunosuppression regimen was maintained continuously. In subsequent follow-up, 1 patient died from BC metastasis, 1 from sepsis, 1 from chronic renal failure, and 3 remained alive. The probability of survival at 5 years was 40%, and median survival was established at 5 years. ConclusionsThe incidence of BC in patients undergoing solid organ transplant and the proportion of patients diagnosed in early stages does not differ from non-transplant patients diagnosed with BC, which questions the role of immunosuppression in the genesis and aggressiveness of BC in transplant patients. Surgery may offer acceptable results in early stages, with acceptable rates of perioperative morbidity and mortality.

LUNG CANCER IN LUNG TRANSPLANT RECIPIENT TREATED WITH PHOTODYNAMIC THERAPY AND RADIOTHERAPY

INTRODUCTION:An increased risk of malignancies is a recognized complication of organ transplantation. An early stage bronchogenic carcinoma is not a common finding after lung transplantation. Treatment options for endobronchial tumors include photodynamic therapy.

Histological types and significance of bronchial epithelial dysplasia

Pulmonary epithelium is known to undergo a preneoplastic process prior to the development of lung carcinoma. Squamous dysplasia and atypical adenomatous hyperplasia have been identified and classified as preinvasive lesions of squamous cell carcinoma and peripheral pulmonary adenocarcinoma, respectively. However, these commonly recognized preinvasive lesions do not completely explain the development of all histological types of lung carcinoma. By examining 114 resection lung specimens, we concluded that there are four histological patterns of bronchial epithelial dysplasia based on morphological features (basal cell dysplasia, columnar cell dysplasia, bronchial epithelial dysplasia with transitional differentiation, and squamous dysplasia). The histological patterns were further characterized by immunohistochemistry. Basal cell dysplasia was focally positive for cytokeratin (CK) 17 and 10/13; columnar cell dysplasia was generally positive for CK7, 8, and 18; bronchial epithelial dysplasia with transitional differentiation had a heterogeneous immunoprofile, while squamous dysplasia was positive for CK10/13 and focally positive for CK17. Various degrees of abnormal expression of p53 and Ki-67 were found in the different types of bronchial epithelial dysplasia. The cases were divided into three groups based on degree and extent of bronchial epithelial dysplasia. By Crosstabs McNemar test, the Mann–Whitney U-test (for two independent groups), the Kruskal–Wallis one-way nonparametric ANOVA (for >2 independent groups) and Spearman correlation analysis, the degree and extent of bronchial epithelial dysplasia was shown to be positively correlated with the incidence of bronchogenic carcinoma and multifocal primary lung carcinoma (P<0.05). These findings indicated the following: (1) bronchial epithelium can develop various patterns of dysplasia with abnormal/ambiguous cell differentiation and abnormal expressions of p53 and Ki-67. Thus, these bronchial epithelial dysplastic lesions may represent a preneoplastic process. (2) The degree of bronchial epithelial dysplasia may significantly predispose individuals to bronchogenic carcinoma and multifocal primary lung carcinoma.

Bronchogenic carcinoma following cardiac transplantation

7292 Background: For decades, elevated risk of certain de novo malignancies following solid-organ transplantation have been reported. In the last several years increased incidence of bronchogenic carcinoma has been variably (1.56 - 4.1% incidence) described as a common non-cutaneous malignancy among heart transplant recipients. Our objective was to systematically review cases of lung cancer following cardiac transplantation at our center. Patients and Methods: 267 patients underwent orthotopic cardiac transplantation at the Ohio State University between 1986 and 2004. Transplant records among the cohort of patients surviving greater than one month (n = 237) were reviewed. Nine patients with bronchogenic carcinoma were identified and their clinical charts reviewed. Results: 3.78% of heart transplant recipients at our center developed bronchogenic carcinoma, the most common non-cutaneous malignancy. Indications for transplant included: ischemic (6), dilated (1), viral (1), and idiopathic (1) cardiomyopathie...

Cáncer de pulmón en el Área Sanitaria de A Coruña: incidencia, abordaje clínico y supervivencia

To determine the incidence, clinical approach, diagnostic delay and survival for bronchogenic carcinoma (BC) in the public health area of A Coruña (Spain). This was a retrospective study of patients with a diagnosis of BC made in 1995 and 1996 in a health care area with 509,000 inhabitants. For analysis we gathered demographic, clinical and cyto-histologic data and analyzed diagnostic delay, extension of disease and time of death. Crude, age-specific and age-standardized incidences were calculated. BC was diagnosed in 378 patients (95% men and 5% women). The crude incidence was 37 per 100,000 inhabitants (73.7 per 100,000 men and 3 per 100,000 women) and the age-standardized incidence was 21.7 per 100,000. Diagnosis was by cyto-histology in 87% of the cases, and the most frequent biopsy finding was epidermoid carcinoma. Diagnosis was by clinical or radiologic findings for 13.7%, and patients in that group were older and had greater comorbidity. No symptoms were present in 13% and in those patients diagnosis was earlier, with non-small BC predominating and 60% treated surgically. The diagnostic delay (time from the first symptom to histologic confirmation) was 2.5 months (median, 2.1), and length of delay did not affect survival. Surgery was performed in 23% of the patients with non-small BC. The median survival was 7.1 months (5.2 months for patients who were not treated surgically, and 37.6 for those who were). The incidence of BC in men in our study is consistent with that reported for other Spanish regions, although the incidence we observed for women is much lower. Diagnostic delay did not affect survival. The percentage of patients with surgical-stage disease is very low and survival is very short. These findings support the need for early diagnosis.

Bronchogenic carcinoma complicating lung transplantation

Background Malignancy is a well-recognized complication of solid-organ transplantation. Although a variety of malignancies have been reported in lung transplant recipients, a paucity of information exists regarding the incidence and clinical course of bronchogenic carcinoma in this patient population. Methods We conducted a retrospective cohort study of our lung transplant experience at the University of Pennsylvania. Results We identified 6 patients with bronchogenic carcinoma detected at the time of, or developing after, transplantation. The incidence of bronchogenic carcinoma was 2.4%. All patients with lung cancer had a history of smoking, with an average of 79 ± 39 pack-years. A total of 5 patients had chronic obstructive pulmonary disease, and 1 had idiopathic pulmonary fibrosis. Lung cancers were all of non–small-cell histology and first developed in native lungs. Three patients had bronchogenic carcinoma at the time of surgery. The remaining 3 patients were diagnosed between 280 and 1,982 days post-transplantation. Of the 6 patients, 4 presented with a rapid course suggestive of an infectious process. The 1- and 2-year survival rates after diagnosis were 33% and 17%, respectively. Conclusion Lung transplant recipients are at risk for harboring or developing bronchogenic carcinoma in their native lungs. Rapid progression to locally advanced or metastatic disease commonly occurs, at times mimicking an infection. Bronchogenic carcinoma should be considered in the differential diagnosis of pleuroparenchymal processes involving the native lung.

Bronchogenic carcinoma in lung transplant recipients

Although lung transplant recipients have a higher prevalence of non-melanoma skin cancers and lymphoma than the general population, the same has not been noted for bronchogenic carcinoma. If an increased prevalence of bronchogenic carcinoma exists, contributing factors may include the high rate of previous tobacco use in this population and/or the chronic immunosuppression used to prevent allograft rejection. With time, the incidence of bronchogenic carcinoma in the lung transplant population is likely to parallel the increasing longevity and number of transplanted individuals. We describe 2 cases of bronchogenic carcinoma in lung transplant recipients that demonstrate the morbidity associated with the discovery or development of bronchogenic carcinoma in this population.

ATYPICAL METAPLASIA AND INCIDENCE OF BRONCHOGENIC CARCINOMA

The prognostic implication of atypical squamous metaplasia of the respiratory tract has been uncertain, especially for mild atypia. The relation between degree of severity of atypical metaplasia as detected by sputum cytology and incidence of bronchogenic carcinoma was assessed among 14,414 men aged 45 years or older who smoked one or more packs of cigarettes per day. Trial participants underwent sputum cytologic evaluations every 4 months for an average of 7.4 years as part of the Cooperative Early Lung Cancer Detection Program of the National Cancer Institute and were followed for the development of lung cancer between 1971 and 1983 at three institutions: The Johns Hopkins University, the Memorial Sloan-Kettering Cancer Center, and the Mayo Clinic. Analysis with logistic regression controlling for age, race, occupational exposures to lung carcinogens, average number of cytology records per year, and smoking habits revealed that the estimate of the relative rate (RR) of developing bronchogenic carcinoma was greater among men who had mild atypia as compared with men who had negative cytology readings, but there were marked differences among institutions (RR = 1.1, 95% confidence interval (Cl) 0.8-1.5 at The Johns Hopkins University; RR = 1.6, 95% Cl 1.1-2.5 at the Memorial Sloan-Kettering Cancer Center; and RR = 2.5, 95% Cl 1.6-4.0 at the Mayo Clinic). Results suggest that mild atypia as detected by cytologic evaluation of sputum is an indicator of a modest elevation in risk of bronchogenic carcinoma.

Effects of crocidolite and chrysotile asbestos on cellular uptake and metabolism of benzo(a)pyrene in hamster tracheal epithelial cells.

The incidence of bronchogenic carcinoma is increased substantially in asbestos workers who smoke. We used several approaches to determine possible mechanisms of synergism at the cellular level between asbestos and the polycyclic aromatic hydrocarbon (PAH), benzo(a)pyrene (BaP), a chemical carcinogen in cigarette smoke. Specifically, we hypothesized that cellular uptake and metabolism of BaP might be facilitated when the hydrocarbon was coated on asbestos. In addition, we were interested in whether asbestos, alone or in combination with BaP, caused single strand breakage of DNA in epithelial cells of the airway. UICC reference samples of crocidolite and chrysotile were coated with 3H-BaP before their addition to monolayers of hamster tracheal epithelial cells. In comparative studies, 3H-BaP at identical amounts was added to cells in culture medium. At intervals thereafter, uptake of BaP by cells was documented by scintillation spectrometry and by autoradiography. In addition, cells and media were assayed by use of high pressure liquid chromatography (HPLC) to demonstrate the water-soluble metabolites of BaP. The integrity of DNA was monitored by alkaline elution at intervals after exposure of tracheal cells to various concentrations of asbestos, BaP and BaP-coated asbestos. A rapid transfer of BaP to cells occurred after addition of BaP-coated asbestos to cultures. When BaP was adsorbed to both types of fibers before their addition to cultures, 70% of the total BaP introduced entered the cell within 1 hr; 50% remained intracellular after 8 hr. In contrast, if identical amounts of BaP were added directly to medium, an initial influx of 20% was observed and cells retained only 5% of the initial amount at 8 hr.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanisms of asbestos carcinogenesis

A striking synergistic effect on tumor induction is seen when asbestos and polycyclic hydrocarbons (PCH) are inhaled by or instilled intratracheally into rodents. This observation supports the results of epidemiologic studies indicating that the incidence of bronchogenic carcinoma is increased substantially in smokers occupationally exposed to asbestos. To determine the mechanisms of asbestos-induced carcinogenesis at the cellular level, cell and organ cultures of tracheobronchial epithelium were examined morphologically and biochemically after their exposure to asbestos with and without the adsorption of PCH to its surfaces. Asbestos was phagocytized by the basal cells of the epithelium. The mineral stimulated cellular division, hyperplastic and metaplastic changes, and induction of Na +K + ATPase, a marker enzyme for the plasma membrane. The metabolism of 3-methyl-cholanthrene (3 MC), as determined by aryl hydrocarbon hydroxylase (AHH) activity in monolayers of epithelial cells after their exposure to both asbestos and 3 MC, was potentiated. A hypothetical construct depicting the role of asbestos in carcinogenesis of the respiratory tract is presented.

Evaluation of Primary Carcinoma of the Lung and Survival Rate after Curative Resection in a Large City Hospital

Los autores exponemos nuestra experiencia en el diagnóstico de la hidatidosis pulmonar, presentando 76 quistes hidatídicos en 72 pacientes estudiados.Destacan la importancia de la epidemiología, una exhaustiva historia clínica y el escaso valor de la exploración física, así como los datos de laboratorio general. Consideramos la intradermorreacción de Cassoni como la prueba biológica más eficaz, preponderando sobre todo el estudio radiológico simple y tomográfico, así como la tomografía axial computarizada (TAC) y ecografía, encontrando poco valor a la broncoscopia, broncografía, gammagrafía pulmonar, citología del esputo y arteriografia pulmonar.Al final exponemos el exacto valor de la toracotomía exploradora a veces como el único medio diagnóstico para esta afección.We describe our experience in the diagnosis of pulmonary hydatidosis with seventy-two patients in whom seventy-six hydatid cysts were seen.Factors of importance were: epidemiology, exhaustive clinical history, low valué of physical examination and general laboratory findigns.We consider Cassoni’s intradermal reaction as the most significant biological test. Simple radiologic and tomographic studies together with computed axial tomography (TAC) and echography are more valuable diagnostic procedures than are bronchoscopy, bronchography, pulmonary gammagraphy, pulmonary arteriography and sputum cytology.The valué of thoracotomy which at times may be the only exploratory procedure possible for the diagnosis of hydatidosis, is also discussed.

Mesothelioma and Its Association With Asbestosis

Within a three-year period in a community hospital, 17 cases of mesothelioma, nine of the pleura and eight of the peritoneum, were found at surgery. Two of our patients contracted this malignancy with only environmental exposure consisting of living in a community adjacent to the asbestos mill. In the same hospital, there has been a high incidence of bronchogenic carcinoma with asbestosis. A review of the autopsy material of the past decade brought to light only one additional case. It is our belief that the incidence of mesothelioma is increasing as is the incidence of asbestosis, with the increasing application of this product in many different industries.

AN AUTOPSY SURVEY OF BANTU SOUTH AFRICAN COAL-MINERS.

An autopsy survey of 1,010 Bantu South African coal-miners has been carried out in order to ascertain the commonest causes of death and the incidence of cardiorespiratory tuberculosis and of coal-workers9 pneumoconiosis. These are consecutive autopsy cases. By law, all miners who die from any cause whatsoever, while still employed by the mines immediately before death, must be autopsied, but few autopsies are performed on repatriated miners who die in their homes. For this reason a serious bias has taken place and this limits the possibility of generalizing from this paper. The commonest cause of death was multiple injuries. Primary carcinoma of the liver was the commonest malignancy and the incidence of bronchogenic carcinoma was low. These are the usual findings in the Bantu. Active tuberculosis of the respiratory organs was found in 12% of cases. Coal-workers9 pneumoconiosis was present in 26·8%, and 94% of these cases were of the simple type. There were only 17 cases of progressive massive fibrosis, and this is due to the fact that few autopsies were carried out on such cases. Active tuberculosis of the respiratory organs was present in 21% of cases with simple coal-workers9 pneumoconiosis. The commonest cardiac lesion was chronic non-specific adhesive pericarditis. Myocardial infarction was absent in this series but this is not unusual as infarction of the heart is rare in the Bantu.

Association of bronchogenic carcinoma and active pulmonary tuberculosis; with report of four cases.

The history of coexistant bronchogenic carcinoma and active pulmonary tuberculosis has been reviewed. The literature reveals that bronchogenic carcinoma occurred in 1.4 per cent of autopsied cases of active pulmonary tuberculosis. Conversely, active pulmonary tuberculosis occurred in 6.4 per cent of the bronchogenic carcinomas in a review of recent autopsy series. Four autopsied cases of coexistent bronchogenic carcinoma and active pulmonary tuberculosis have been reported. There were 726 cases of active pulmonary tuberculosis in the past 25 years, so the incidence of bronchogenic carcinoma was 0.6 per cent in this group. In the same period 96 bronchogenic carcinomas were autopsied, so that 4.2 per cent of these patients had associated active pulmonary tuberculosis. Although the associated diseases may occur coincidentally, at times bronchogenic carcinoma may activate pre-existing pulmonary tuberculosis.

Bronchogenic carcinoma; its frequency, diagnosis, and early treatment.

The incidence of bronchogenic carcinoma is increasing more rapidly than that of any other cancer. In 1912 Adler, 1 who was able to collect only 374 cases of cancer of the lung, stated, On one point, however, there is complete consensus of opinion and that is that primary malignant neoplasms of the lung are among the rarest form of disease. Whereas it was an infrequent lesion 40 years ago, it has become one of the most frequent malignant lesions encountered in men. In the 10 years from 1938 to 1948 the number of fatalities from bronchogenic carcinoma in the United States increased 144%, from 6,732 in 1938 to 16,450 in 1948. In this same period of time the total cancer deaths from all types of cancer, increased 31%, from 149, 214in 1938 to 195,594 in 1948. From 1920 to 1948 the death rate from bronchogenic carcinoma per 100,000 population in the

Roentgen evidence of bronchogenic carcinoma.

Whether the increasing incidence of bronchogenic carcinoma is real or apparent has been discussed to a considerable extent in recent years. One important factor in earlier discovery of the disease has been improved technics in roent-genographic diagnosis. Diagnostic procedures and management of bronchogenic carcinoma are presented in a series of illustrative cases, with emphasis on the problems facing the radiologist.

SMOKING and bronchogenic carcinoma.

HomeRadiologyVol. 56, No. 1 PreviousNext EditorialSmoking and Bronchogenic CarcinomaPublished Online:Jan 1 1951https://doi.org/10.1148/56.1.116MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In AbstractBronchogenic carcinoma as a cause of death has shown a progressive increase during the past several decades. Many theories have been advanced to account for this remarkable change in the vital statistics. Prolongation of the life span must be accorded some consideration, although the incidence of bronchogenic carcinoma has risen relatively more than that of cancer as a whole. The inhalation of gas engine exhaust fumes has been blamed by some, and occupational hazards may play a role. A number of recent studies have indicted tobacco smoking as a possible etiologic factor, and statistical studies strongly support this theory.Wynder and Graham have made a study of 684 cases of proved bronchogenic carcinoma. In 605 of these (in men) they found that over 50 per cent of the patients were excessive or chain smokers compared to 19 per cent of a general hospital group without cancer. Only 2 per cent of the lesions occurred in non-smokers or minimal smokers. In 96 per cent of the carcinoma series there was a history of smoking for over twenty years, which may account for the greater incidence of the disease in men, as excessive smoking by women is of relatively recent development. Wynder and Graham believe that there may be a lag period of ten years or more, even after cessation of smoking, before the development of the neoplasm. A very high percentage (94.1 per cent) of the patients smoked cigarettes, and it is believed that the practice of inhalation among cigarette smokers may be of significance.In a similar study, Doll and Hill reported their observations in 709 cases of carcinoma of the lung from twenty London hospitals. Of the men in this series 0.3 per cent and of the women 31.7 per cent were non-smokers. Among control non-cancer groups, the figure for men was 4.2 per cent and for women 53.3 per cent. Of the smokers with carcinoma of the lung, a high proportion were in the “heavy smoking” category ; 26 per cent of the male patients and 14.6 per cent of the female carcinoma patients smoked the equivalent of 25 cigarettes per day, while only 13.5 per cent of the male and none of the female non-cancer control patients smoked as much. Cigarette smoking was found to be more closely related to carcinoma of the lung than pipe smoking.Levin, Goldstein, and Gerhardt studied the smoking habits of patients with cancer involving both the lung and lip. Their data indicate that cancer of the lung occurs more than twice as frequently among those who have smoked cigarettes for twenty-five years than among non-smokers of comparable age.The offending agent is not indicated from any of these studies, as distillates from tobacco have never been proved to be carcinogenic. Doll and Hill suggest that some other agent, such as spray material on tobacco plants, may be responsible.Article HistoryPublished in print: Jan 1951 FiguresReferencesRelatedDetailsRecommended Articles RSNA Education Exhibits RSNA Case Collection Vol. 56, No. 1 Metrics Altmetric Score PDF download