Disparity in age at lung cancer diagnosis between current and former smokers.

PURPOSE: In a previous study of smoking cessation in veterans with lung cancer, we noted as an incidental finding that current smokers were much younger than former smokers at diagnosis. To confirm and extend this observation, we analyzed the association of smoking status with age at diagnosis and survival of lung cancer patients. METHODS: The Jefferson Cancer Registry collects information on all cancer patients registered at this hospital. Information on smoking status has been recorded since 1995. We determined age at diagnosis and survival of current and former smokers with lung cancer. RESULTS: 5111 lung cancer cases were identified in the registry from 1995 to 2011 inclusive. Smoking status was recorded in 4687 cases (91.7%). Of these, 1859 (39.7%) were current, 2423 (51.7%) were former, and 405 (8.6%) were never smokers. There was a 6-year difference in median age at lung cancer diagnosis between the current (63 years) and former smokers (69 years) (P < 0.0001). The median survival was 12.1 months for current versus 14.5 months for former smokers (P < 0.0001). CONCLUSIONS: These results confirm and extend our observation that among patients diagnosed with lung cancer, current smokers are younger than former smokers. The possible explanations include higher competing causes of death and increased risk of lung cancer among current smokers as well as increasing proportions of former smokers in older populations. Ongoing exposure to tobacco carcinogens may accelerate the development of lung cancer in continuing smokers. This provides more incentive for smokers to quit at the earliest age possible.

The Role of Telemedicine in Providing Thoracic Oncology Care to Remote Areas of British Columbia.

PURPOSE OF REVIEW: The purpose of this study is to review the role of telemedicine in providing oncology care; we describe our long-standing, high-volume telemedicine experience. RECENT FINDINGS: The Interior Health Thoracic Surgical Group (IHTSG) uses telemedicine, through Virtual Thoracic Surgical Clinics (VTSC), to provide service to remote patients. The IHTSG serves a population of 1.01 million people over an area of 807,538 km2 (1.3 persons/km2) in the Interior and North of British Columbia, Canada. Between 2003 and 2015, the IHTSG conducted 15,073 telemedicine patient encounters at 63 geographic sites. Telemedicine saved these patients a total travel distance of 11.5 million km-an average of 766 km per patient. VTSC supports and strengthens the Hub and Spoke model of healthcare delivery-patients residing remotely can easily access centrally delivered service. Telemedicine makes specialized care available to all patients by overcoming a major impediment to access, namely distance.

Acute activation, desensitization and smoldering activation of human acetylcholine receptors.

The behavioral effects of nicotine and other nicotinic agonists are mediated by AChRs in the brain. The relative contribution of acute activation versus chronic desensitization of AChRs is unknown. Sustained "smoldering activation" occurs over a range of agonist concentrations at which activated and desensitized AChRs are present in equilibrium. We used a fluorescent dye sensitive to changes in membrane potential to examine the effects of acute activation and chronic desensitization by nicotinic AChR agonists on cell lines expressing human α4ß2, α3ß4 and α7 AChRs. We examined the effects of acute and prolonged application of nicotine and the partial agonists varenicline, cytisine and sazetidine-A on these AChRs. The range of concentrations over which nicotine causes smoldering activation of α4ß2 AChRs was centered at 0.13 µM, a level found in smokers. However, nicotine produced smoldering activation of α3ß4 and α7 AChRs at concentrations well above levels found in smokers. The α4ß2 expressing cell line contains a mixture of two stoichiometries, namely (α4ß2)2ß2 and (α4ß2)2α4. The (α4ß2)2ß2 stoichiometry is more sensitive to activation by nicotine. Sazetidine-A activates and desensitizes only this stoichiometry. Varenicline, cytisine and sazetidine-A were partial agonists on this mixture of α4ß2 AChRs, but full agonists on α3ß4 and α7 AChRs. It has been reported that cytisine and varenicline are most efficacious on the (α4ß2)2α4 stoichiometry. In this study, we distinguish the dual effects of activation and desensitization of AChRs by these nicotinic agonists and define the range of concentrations over which smoldering activation can be sustained.

Spontaneous smoking cessation before lung cancer diagnosis.

INTRODUCTION: We have observed that many patients with lung cancer stop smoking before diagnosis, usually before clinical symptoms, and often without difficulty. This led us to speculate that spontaneous smoking cessation may be a presenting symptom of lung cancer. METHODS: Patients from the Philadelphia Veterans Affairs Medical Center with lung cancer and for comparison, prostate cancer and myocardial infarction underwent a structured interview about their smoking habits preceding diagnosis. Severity of nicotine addiction was graded using the Fagerström Test for Nicotine Dependence. Among former smokers, dates of cessation, onset of symptoms, and diagnosis were recorded. Difficulty quitting was rated on a scale of 0 to 10. Distributions of intervals from cessation to diagnosis were compared between groups. RESULTS: All 115 patients with lung cancer had been smokers. Fifty-five (48%) quit before diagnosis, and only six of these (11%) were symptomatic at quitting. Patients with lung cancer who quit were as dependent on nicotine, when smoking the most, as those who continued to smoke, unlike the other groups. Despite this, 31% quit with no difficulty. The median interval from cessation to diagnosis was 2.7 years for lung cancer, 24.3 years for prostate cancer, and 10.0 years for patients with myocardial infarction. CONCLUSIONS: These results challenge the notion that patients with lung cancer usually quit smoking because of disease symptoms. The hypothesis that spontaneous smoking cessation may be a presenting symptom of lung cancer warrants further investigation.

The HDAC inhibitor panobinostat (LBH589) inhibits mesothelioma and lung cancer cells in vitro and in vivo with particular efficacy for small cell lung cancer.

Lung cancer is the leading cause of cancer deaths in the United States. Current therapies are inadequate. Histone deacetylase inhibitors (HDACi) are a recently developed class of anticancer agents that cause increased acetylation of core histones and nonhistone proteins leading to modulation of gene expression and protein activity involved in cancer cell growth and survival pathways. We examined the efficacy of the HDACi panobinostat (LBH589) in a wide range of lung cancers and mesotheliomas. Panobinostat was cytotoxic in almost all 37 cancer cell lines tested. IC(50) and LD(50) values were in the low nmol/L range (4-470 nmol/L; median, 20 nmol/L). Small cell lung cancer (SCLC) cell lines were among the most sensitive lines, with LD(50) values consistently <25 nmol/L. In lung cancer and mesothelioma animal models, panobinostat significantly decreased tumor growth by an average of 62% when compared with vehicle control. Panobinostat was equally effective in immunocompetent and severe combined immunodeficiency mice, indicating that the inhibition of tumor growth by panobinostat was not due to direct immunologic effects. Panobinostat was, however, particularly effective in SCLC xenografts, and the addition of the chemotherapy agent etoposide augmented antitumor effects. Protein analysis of treated tumor biopsies revealed elevated amounts of cell cycle regulators such as p21 and proapoptosis factors, such as caspase 3 and 7 and cleaved poly[ADP-ribose] polymerase, coupled with decreased levels of antiapoptotic factors such as Bcl-2 and Bcl-X(L). These studies together suggest that panobinostat may be a useful adjunct in the treatment of thoracic malignancies, especially SCLC.

A population-based study of lung carcinoma in Pennsylvania: comparison of Veterans Administration and civilian populations.

BACKGROUND: Lung carcinoma remains the major cause of cancer death in North America and is even more common among military veterans. The objective of this study was to determine whether there were differences in the characteristics and survival of Pennsylvania patients with lung carcinoma in the Veterans Administration (VA) hospital system compared with patients in the rest of the state. METHODS: The Pennsylvania Cancer Registry was used to identify all patients who were diagnosed with lung carcinoma in the State of Pennsylvania from 1995 to 1999. Patients who were treated within the Veterans Administration Health Care Network were identified by hospital code. Survival from the date of diagnosis of lung carcinoma was determined by using the Pennsylvania state mortality files from 1995 to 2001. RESULTS: From 1995 to 1999, 48,994 patients were newly diagnosed with lung carcinoma in Pennsylvania (41.2% women), including 856 patients in the VA system (6 women). The current analysis was restricted to male patients (n = 28,798 men). There was no major difference in age of VA patients compared with non-VA patients, and the proportions of patients who had localized or regional stage disease were similar (49% of VA patients vs. 48% of non-VA patients). The proportion of black patients was much higher in the VA population (23%) compared with the non-VA population (9%). The median survival was 6.3 months for VA patients compared with 7.9 months for patients in the rest of the state, and the 5-year overall survival rate was 12% for VA patients compared with 15% for patients in the rest of the state. When survival was analyzed according to race, there was a significant difference in the age-adjusted survival of white patients in the VA system compared with patients in the rest of the state (P = 0.0007), but no significant difference was observed among black patients (P = 0.92). CONCLUSIONS: The overall survival of VA patients with lung carcinoma in Pennsylvania was inferior to that of patients in the remainder of the state and this was due primarily to differences in survival among the white patients. Further investigation will be necessary to determine whether this disparity was caused by differences in socioeconomic status or comorbidities or whether there are systematic differences in the diagnosis, staging, or treatment of lung carcinoma between VA patients and civilian patients.

Clinical implication of p53 mutation in lung cancer.

Lung cancer development involves multiple genetic abnormalities leading to malignant transformation of the bronchial epithelial cells, followed by invasion and metastasis. One of the most common changes is mutation of the p53 tumor suppressor gene. The frequency of p53 alterations in lung cancer is highest in small cell and squamous cell carcinomas. A genetic "signature" of the type of p53 mutations has been associated with carcinogens in cigarette smoke. The majority of clinical studies suggest that lung cancers with p53 alterations carry a worse prognosis, and may be relatively more resistant to chemotherapy and radiation. An understanding of the role of p53 in human lung cancer may lead to more rational targeted approaches for treating this disease. P53 gene replacement is currently under clinical investigation but clearly more effective means of gene deliver to the tumor cells are required. Novel approaches to lung cancer therapy are needed to improve the observed poor patient survival despite current therapies.

Clinical implications of p53 mutations in lung cancer.

The process of bronchial carcinogenesis is characterized by accumulated genetic abnormalities which ultimately lead to malignant transformation of bronchial epithelial cells, followed by invasion and metastasis. One of the most common and consistent of these genetic lesions is inactivation of the p53 tumor suppressor gene by mutation or deletion. The frequency of p53 alterations in lung cancer is highest in those subtypes of bronchial carcinomas that are most consistently associated with smoking, especially SCLC and squamous cell carcinomas. The frequency is lower in adenocarcinomas, in which the association with smoking, although present, is not as strong. The frequency of p53 abnormalities is higher in patients with greater cumulative tobacco exposure. Tobacco-specific carcinogens, in particular BPDE, cause a unique spectrum of p53 mutations, quite distinct from those found in cancers that are not associated with smoking. This characteristic genetic "signature" may persist even decades following smoking cessation. The prognostic significance of p53 mutations in lung cancer is not entirely clear despite the multitude of clinical studies that have been carried out. Nevertheless, the majority of clinical studies suggest that lung cancers with p53 alterations carry a worse prognosis. Furthermore, those tumors with mutant p53 may be relatively more resistant to chemotherapy and radiation. An understanding of the role of p53 in human lung cancer may lead to more rational targeted approaches for treating this disease. For example, the observation that the introduction of wild-type p53 into lung cancer cells with mutant or deleted p53 may reverse the malignant phenotype despite the presence of multiple other genetic abnormalities (14) suggests that replacement of this gene may be an effective clinical strategy. Preclinical and early clinical studies indicate that this is a promising approach, but clearly more effective means of gene delivery to the tumor cells are required (127-129), as discussed elsewhere in this volume.

Clinical and molecular features of small cell lung cancer.

Small cell lung cancer is a common malignancy found in smokers. It has a poor long-term prognosis despite initial sensitivity to chemotherapy and radiation. The clinical features of small cell lung cancer are unique among lung cancers and other neuroendocrine tumors. In order to better understand the pathogenesis of small cell lung cancer, there has been a great effort to identify the genetic alterations involved in the development and progression of the disease, and to translate these to novel molecular strategies for treatment.