Tobacco use and cancer causation: association by tumour type

Effect of prior malignancy on survival after cardiac surgery

BACKGROUND

The number of patients with a previously treated tumor, needing cardiac surgery is increasing. Whether this operation in these patients is justified is determined by the long-term outcome.

METHODS

Of 8620 patients referred for cardiac surgery, 205 had a documented malignant tumor. The time interval between the occurrence of the tumor and the cardiac surgery was recorded. These patients were matched with 205 patients without a tumor according to age, gender, comorbidity and type of cardiac surgery. The patients were followed retrospectively. A chi(2) Kaplan Meier and Cox' regression analysis were performed.

RESULTS

During follow-up, 95.8% of the patients were traced (2794 patient years). Univariate analysis showed that 5- and 10-year survival was better in patients without a malignant tumor in the history (0.91 +/- 0.02 versus 0.72 +/- 0.03 and 0.73 +/- 0.04 versus 0.40 +/- 0.05; p < 0.0001). For shorter time intervals, mortality for all causes and mortality due to the tumor increase significantly (p < 0.0001). Multivariate analysis identified 4 independent variables: a malignant tumor in the history (p < 0.001), chronic obstructive pulmonary disease (p = 0.003), age (p = 0.001), and impaired left ventricular function (p = 0.035)

CONCLUSIONS

A malignant tumor in the history is the most prognostic factor after cardiac surgery, but the operation is still rewarding. Fatal progression of the tumor is seen if the time interval between the occurrence of the malignant tumor and cardiac surgery is short. Other unfavorable factors are decreased left ventricular function, chronic obstructive pulmonary disease and high age.

Esophageal squamous cell cancer in patients with head and neck cancer: Prevalence of human papillomavirus DNA sequences

An etiologic role for human papillomavirus (HPV) infections in either head and neck (HNC) or esophageal carcinogenesis remains debatable. Patients with head and neck cancer are at high risk for developing a second esophageal squamous cell cancer (ESCC). The aim of our study was to determine whether HPV infections play a role in this multifocal carcinogenesis. Samples from 2 groups of HNC patients were studied: Random esophageal biopsies were collected from the first group of 60 patients who had been screened for asymptomatic ESCC. The second group consisted of 21 patients with pairs of HNC and ESCC. Both the fresh frozen biopsy samples of the first group and the paraffin-embedded specimens of the second group were evaluated for the presence of HPV DNA sequences by PCR amplification, cloning and sequencing. HPV DNA sequences were detected in 66.7% of normal/inflammatory (34/51) and dysplastic and malignant (6/9) esophageal tissues from HNC patients being screened endoscopically. Similarly, in the second group of 21 patients with both HNC and ESCC, HPV DNA sequences were demonstrated in 13 (61.9%) of the HNC biopsies and in 14 (66.7%) of the ESCC biopsies. The prevalence of high-risk-type HPV 16 was low (5/51, 9.8%) in normal/inflammatory esophageal mucosa but higher (10/24, 47.6%) in ESCC. The low-risk HPV 11 was present in 37.3% (19/51) of normal/inflammatory, 66.7% (4/6) of dysplastic and 28.9% (13/45) of the carcinoma samples. The same HPV type was present in only 3/21 pairs of HNC and ESCC samples, suggesting that a clonal expansion from the HNC to a subsequent ESCC, or visa versa, is unlikely. The high prevalence of "low-risk" HPV infections points to the need for studies on possible interactions of these infections with the use of alcohol and tobacco in the pathogenesis of these tumors.

Nicotine-related alkaloids and metabolites as inhibitors of human cytochrome P-450 2A6

S-(-)-Nicotine and 13 of the most prevalent nicotine-related alkaloids and metabolites (i.e., S-(-)-nornicotine, myosmine, beta-nicotyrine, S-cotinine, S-norcotinine, S-(-)-nicotine N-1'-oxide, S-(-)-nicotine Delta1'-5'-iminium ion, S-(-)-anabasine, S-(-)-N-methylanabasine, anabaseine, S-(-)-anatabine, nicotelline, and 2,3'-bipyridyl) were evaluated as inhibitors of human cDNA-expressed cytochrome P-450 2A6 (CYP2A6) mediated coumarin 7-hydroxylation. Tobacco alkaloids myosmine, S-(-)-nornicotine, S-cotinine, S-norcotinine, S-(-)-nicotine N-1'-oxide, S-(-)-nicotine Delta1'-5'-iminium ion, S-(-)-N-methylanabasine, anabaseine, and nicotelline had Ki values for inhibition of coumarin 7-hydroxylation ranging from 20 microM to more than 300 microM whereas nicotine and S-(-)-anatabine were much more potent (i.e. 4.4 and 3.8 microM, respectively). The tobacco alkaloids 2,3'-bipyridyl (7.7 microM) and S-(-)-anabasine (5.4 microM), were somewhat less potent compared with S-(-)-nicotine or S-(-)-anatabine in inhibition of human CYP2A6. beta-Nicotyrine, in which the N-methylpyrrolidino moiety of nicotine was replaced by the aromatic N-methylpyrrole ring, was shown to inhibit human CYP2A6 with much greater potency (Ki=0.37 microM) compared with S-(-)-nicotine. Among the compounds examined, only nicotine and beta-nicotyrine were mechanism-based inhibitors of human CYP2A6. The potency of the mechanism-based CYP2A6 inhibitors suggests that, for smokers, modulation of CYP2A6 may be greater than that predicted on the basis of serum concentration of these alkaloids. Our results indicate that the prominent nicotine-related alkaloid beta-nicotyrine present after smoking potently inhibits human CYP2A6.

Chemical composition, cytotoxicity and mutagenicity of smoke from US commercial and reference cigarettes smoked under two sets of machine smoking conditions

Eight blended US market cigarettes, two blended reference cigarettes, one Bright tobacco only reference cigarette and an electrically heated prototype cigarette (EHC) were smoked under US Federal Trade Commission (FTC)/International Organisation for Standardisation (ISO) conditions and under Massachusetts Department of Public Health (MDPH) conditions. Smoke was analysed for chemical composition and in vitro toxicity. Yields (quantity/cigarette) of smoke constituents were higher under MDPH conditions compared to FTC/ISO conditions (market and reference average approximately 2.5 times; EHC approximately 1.6 times). Consistent with the higher yields, in vitro toxicity per cigarette was also higher under MDPH conditions. Concentrations (quantity/mg TPM) of nearly all smoke constituents measured decreased with increasing total particulate matter (TPM) yields as regression analyses indicated. Higher TPM yields also tended to be associated with slightly less cytotoxic and mutagenic activity per milligram TPM. Blended reference cigarettes tracked market cigarettes with similar TPM yield. The Bright cigarette displayed high cytotoxicity but low mutagenicity, while in vitro activity of the EHC was remarkably low. The TPM-dependent decreases for the market range of 5-20 mg TPM/cigarette were about 20%, irrespective of whether the increased yields were due to smoking conditions or cigarette construction. At the same TPM yield, the smoke constituent concentrations and in vitro toxicity were similar for low- and high-yield cigarettes.

Effects of Smokeless Tobacco "Maras Powder" Use on Respiratory Functions

In Turkey, "Maras Powder," which is a kind of powder yielded from the shields of tobacco, is widely used as smokeless tobacco through buccal mucosa or together with cigarette. Maras powder, composed of ash and a plant named Nicotiana Rustica Linn, is sometimes used to give up smoking. The present study was aimed to investigate the effects of Maras powder use on respiratory functions of healthy subjects who do not have any chronic disease. We found statistically significant differences in percentage of forced expiratory volume in the first second (FEV(1)%) (p = 0.001), the ratio of FEV(1) to forced vital capacity (FEV(1)/FVC) (p = 0.024), percent of maximum expiratory flow rate (FEF(25-75)%) (p = 0.002) and percent of peak expiratory flow (PEF%) (p = 0.037) between cigarette smokers with Maras powder use (n = 23) and control subjects (n = 24). Likewise, when cigarette smokers (n = 24) and control subjects were compared, the differences for all these parameters were significant (p = 0.022, p = 0.048, p = 0.011 and p = 0.047, respectively). Only FEV(1)% and FEF(25-75)% were significantly lower in cigarette smokers with Maras powder use than in Maras powder users (n = 28) (p = 0.011 and p = 0.022, respectively). There was a negative correlation between forced vital capacity and Maras powder use (r = -0.315, p = 0.03). The present study suggests that Maras powder does not cause serious bronchial obstruction. This may be due to usage of the smokeless tobacco through buccal mucosa but not through inhalation as in case of cigarette smoking.

Teachable moments for promoting smoking cessation: the context of cancer care and survivorship

BACKGROUND

There has been a call for comprehensive cancer care that gives greater consideration to changing lifestyle risk factors such as smoking to improve prognosis and long-term health. Cancer diagnosis, treatment, and survivorship offer challenges and opportunities ("teachable moments") to promote smoking cessation.

METHODS

This review provides a rationale for the importance of smoking cessation programs in the cancer context, highlights practice guidelines for the delivery of these interventions, summarizes the challenges to smoking cessation unique to cancer patients, and recommends approaches to capitalize on the cancer context to promote smoking cessation.

RESULTS

Barriers to smoking cessation by patients with cancer include heavy nicotine dependence, urgency of cessation, fatalistic attitudes about cessation benefits, cancer-related psychological distress, treatment factors, and the presence of smokers in the social network. Opportunities to promote cessation include the transition from inpatient to outpatient care, involvement in cancer patient care by family members who smoke, and distribution of clinical feedback (eg, test results).

CONCLUSIONS

Teachable moments in the cancer context are not being fully utilized to promote smoking cessation. Evidence-based guidelines can assist cancer care teams in promoting cessation.

Human papillomavirus and cervical cancer: not just a sexually transmitted disease

The human papillomavirus (HPV) is the cause of virtually all cancers of the cervix, the fourth most common cancer in women in the United States. HPV is sexually transmitted, and the lifetime risk of contracting the virus is estimated to be 75%-90%. New methods of detecting HPV infection and cellular changes (dysplasia) caused by HPV can greatly reduce the mortality associated with this virus. More than 100 types of HPV exist and may be classified as low-, intermediate-, or high-risk in terms of causing cancer. The virus can cause genital warts, subclinical dysplasia, and cancer. Nurses play an important role in educating patients regarding HPV and preventive measures as well as in screening and treatment. Most women diagnosed with HPV need emotional support and factual information provided in a supportive, nonjudgmental manner. Nurses can meet this challenge and make a difference in reducing the incidence and mortality of cervical cancer.