Implementing low-dose computed tomography screening for lung cancer in Canada: implications of alternative at-risk populations, screening frequency, and duration

BACKGROUND

Low-dose computed tomography (ldct) screening has been shown to reduce mortality from lung cancer; however, the optimal screening duration and "at risk" population are not known.

METHODS

The Cancer Risk Management Model developed by Statistics Canada for the Canadian Partnership Against Cancer includes a lung screening module based on data from the U.S. National Lung Screening Trial (nlst). The base-case scenario reproduces nlst outcomes with high fidelity. The impact in Canada of annual screening on the number of incident cases and life-years gained, with a wider range of age and smoking history eligibility criteria and varied participation rates, was modelled to show the magnitude of clinical benefit nationally and by province. Life-years gained, costs (discounted and undiscounted), and resource requirements were also estimated.

RESULTS

In 2014, 1.4 million Canadians were eligible for screening according to nlst criteria. Over 10 years, screening would detect 12,500 more lung cancers than the expected 268,300 and would gain 9200 life-years. The computed tomography imaging requirement of 24,000-30,000 at program initiation would rise to between 87,000 and 113,000 by the 5th year of an annual nlst-like screening program. Costs would increase from approximately $75 million to $128 million at 10 years, and the cumulative cost nationally over 10 years would approach $1 billion, partially offset by a reduction in the costs of managing advanced lung cancer.

CONCLUSIONS

Modelling various ways in which ldct might be implemented provides decision-makers with estimates of the effect on clinical benefit and on resource needs that clinical trial results are unable to provide.

Using the Cancer Risk Management Model to evaluate the health and economic impacts of cytology compared with human papillomavirus DNA testing for primary cervical cancer screening in Canada

BACKGROUND

In Canada, discussion about changing from cytology to human papillomavirus (hpv) dna testing for primary screening in cervical cancer is ongoing. However, the Canadian Task Force on Preventive Health Care has not yet made a recommendation, concluding that the evidence is insufficient.

METHODS

We used the cervical cancer and hpv transmission models of the Cancer Risk Management Model to study the health and economic outcomes of primary cytology compared with hpv dna testing in 14 screening scenarios with varying screening modalities and intervals. Projected cervical cancer cases, deaths, colposcopies, screens, costs, and incremental cost-effectiveness were evaluated. We performed sensitivity analyses for hpv dna test costs.

RESULTS

Compared with triennial cytology from age 25, 5-yearly hpv dna screening alone from age 30 resulted in equivalent incident cases and deaths, but 55% (82,000) fewer colposcopies and 43% (1,195,000) fewer screens. At hpv dna screening intervals of 3 years, whether alone or in an age-based sequence with cytology, screening costs are greater, but at intervals of more than 5 years, they are lower. Scenarios on the cost-effectiveness frontier were hpv dna testing alone every 10, 7.5, 5, or 3 years, and triennial cytology starting at age 21 or 25 when combined with hpv dna testing every 3 years.

CONCLUSIONS

Changing from cytology to hpv dna testing as the primary screening test for cervical cancer would be an acceptable strategy in Canada with respect to incidence, mortality, screening and diagnostic test volumes.

Systematic review and meta-analysis of the accuracy of MRI and endorectal ultrasound in the restaging and response assessment of rectal cancer following neoadjuvant therapy

AIM

Restaging imaging by MRI or endorectal ultrasound (ERUS) following neoadjuvant chemoradiotherapy is not routinely performed, but the assessment of response is becoming increasingly important to facilitate individualization of management.

METHOD

A search of the MEDLINE and Scopus databases was performed for studies that evaluated the accuracy of restaging of rectal cancer following neoadjuvant chemoradiotherapy with MRI or ERUS against the histopathological outcome. A systematic review of selected studies was performed. The methodological quality of studies that qualified for meta-analysis was critically assessed to identify studies suitable for inclusion in the meta-analysis.

RESULTS

Sixty-three articles were included in the systematic review. Twelve restaging MRI studies and 18 restaging ERUS studies were eligible for meta-analysis of T-stage restaging accuracy. Overall, ERUS T-stage restaging accuracy (mean [95% CI]: 65% [56-72%]) was nonsignificantly higher than MRI T-stage accuracy (52% [44-59%]). Restaging MRI is accurate at excluding circumferential resection margin involvement. Restaging MRI and ERUS were equivalent for prediction of nodal status: the accuracy of both investigations was 72% with over-staging and under-staging occurring in 10-15%.

CONCLUSION

The heterogeneity amongst restaging studies is high, limiting conclusive findings regarding their accuracies. The accuracy of restaging imaging is different for different pathological T stages and highest for T3 tumours. Morphological assessment of T- or N-stage by MRI or ERUS is currently not accurate or consistent enough for clinical application. Restaging MRI appears to have a role in excluding circumferential resection margin involvement.

Prospective Study of Early MRI Appearances following Flow-Diverting Stent Placement for Intracranial Aneurysms

BACKGROUND AND PURPOSE

MR imaging findings of aneurysm enlargement, aneurysm wall enhancement, perianeurysmal edema, and embolic phenomena following deployment of flow-diverting stents may be relevant to those patients who subsequently experience procedure-related intracranial hemorrhage. We sought to document the routine early postoperative MR imaging findings following flow-diverting stent insertion.

MATERIALS AND METHODS

Patients requiring flow-diverting stent placement for treatment or retreatment of cerebral aneurysms were prospectively included in the study during a 26-month period. Early postprocedural MR imaging studies were obtained and compared with preoperative imaging. Patient clinical outcome data were also collected.

RESULTS

There were 34 stent-placement procedures during the study period. Aneurysm mural enhancement and mild new perianeurysmal edema were present in 50% and 14%, respectively. Any DWI lesion was present in 57% of cases. New or possibly new foci of susceptibility effect were found ipsilateral to the stent and not associated with diffusion restriction in 66% of cases. There were 2 cases (6%) of parenchymal hemorrhage and 2 major clinical complications (6%) causing permanent morbidity.

CONCLUSIONS

Asymptomatic aneurysm mural enhancement is frequently seen following flow-diverting stent placement and should not necessarily be interpreted as a sign of impending aneurysm rupture. This finding often persists despite complete aneurysm occlusion. New small brain parenchymal susceptibility foci following stent placement have not previously been reported, to our knowledge, but were common in our series.

Primary Sjögren's Syndrome Presenting as Flaccid Quadriparesis

Primary Sjögren's syndrome is an autoimmune disease presenting classically as keratoconjunctivitis sicca. Renal involvement in Sjögrens's syndrome is less common, and the initial presentation with renal complications without any sicca symptoms is extremely rare. The renal involvement may present with symptoms arising from interstitial nephritis, mainly distal renal tubular acidosis.

Primary cell and micromass culture in assessing developmental toxicity

Under the European Commission's New Chemical Policy both currently used and new chemicals should be tested for their toxicities in several areas, one of which was reproductive/developmental toxicity. Thousands of chemicals will need testing which will require a large number of laboratory animals. In vitro systems (as pre-screens or as validated alternatives) appear to be useful tools to reduce the number of whole animals used or refine procedures and hence decrease the cost for the chemical industry. Validated in vitro systems exist for developmental toxicity/embryotoxicity testing. Indeed, three assays have recently been validated: the whole embryo culture (WEC), the rat limb bud micromass (MM), and the embryonic stem cell test (EST). In this article, the use of primary embryonic cell culture, and in particular micromass culture, including a relatively novel chick heart micromass (MM) culture system has been described and compared to the validated D3 mouse embryonic stem cell (ESC) test.

Knowledge, attitudes and practices of barbers about hepatitis B and C transmission in Hyderabad, Pakistan

Hepatitis B and C virus (HBV/HCV) infections are serious global health problems. Shaving by barbers has been identified as the key risk factor for spread of HBV. We conducted a cross-sectional survey of barbers in Hyderabad city, Pakistan in 2007 to establish their knowledge and attitudes to the risk of HBV and HCV transmission and their working patterns. Observations showed that 96.2% washed razors with antiseptic after each client and 95.7% used a new blade with new clients. However, knowledge about the diseases and modes of transmission were poor and only 36.6% knew that hepatitis can be transmitted via shaving instruments. Only 3.2% of 186 barbers were vaccinated against HBV. Strategies are needed for raising awareness and regulations of barbers' practices.

An evaluation of topical and local anesthesia in phacoemulsification

OBJECTIVE

To assess the comparative efficacy of topical and local anesthesia in phacoemulsification.

MATERIAL AND METHODS

The medical records of 186 men and women between the ages of 45-85 years, who underwent elective cataract surgery by phacoemulsification technique, under the care of one surgeon, over a period of one year, from March 1999-March 2000 were reviewed.

RESULTS

Of 186 patients who underwent small incision, self-healing phacoemulsification cataract surgery, 124 received topical and 62 local anesthesia. The most common cataract types were nuclear sclerosis. The duration of surgery with topical anesthesia was shorter. Sutures and eye padding were more frequently applied for procedures done under local anesthesia. Uncorrected visual acuity in the first post-op week was between 20/20-20/50 for 53.6% of the cases done under topical compared to 30.9% in local anesthesia. A similar trend was noted in the visual acuity one month post operatively.

CONCLUSION

The uncorrected visual acuity improves faster and the duration of surgery is shorter when topical anesthesia is used.

Effects of high sugar diets on renal fluid, electrolyte and mineral handling in rats: relationship to blood pressure

OBJECTIVE

We examined whether sugar-induced systolic blood pressure (SBP) elevations in rats may develop, in part, through a mechanism common to salt-induced hypertension, i.e., renal retention of water and salt.

DESIGN

Spontaneously hypertensive rats (SHR) ate four diets: two high (> 50% of calories) and two low (< 12% of calories) in sugar (sucrose). SBP, various urinary parameters, and the renal angiotensin and prostaglandin systems were assessed.

RESULTS

SHR consuming diets high in sugar showed significantly decreased urinary volume and excretion of electrolytes, which coincided with increasing SBP. When low sugar diets replaced high sugar diets, SBP and urinary parameters rapidly returned to baseline. SHR received captopril while consuming high sugar diets, and both SBP and urinary parameters assumed baseline values, comparable to ones seen in SHR consuming low sugar diets. A direct angiotensin II receptor antagonist (DuPont 753) did not influence SBP. However, we found decreased PGE2 excretion in SHR consuming excess sugar.

CONCLUSIONS

Salt and water retention occur early during sugar-induced hypertension due to reduced renal excretion, consistent with some part in the pathogenesis. The effects of high sugar diets on SBP were not due to angiotensin II inhibition, however, decreased availability of vasodilatory prostaglandins may play a role in the renal events and sugar-induced hypertension in SHR.

Rabbit and human renotropin are not epidermal growth factor

Sera obtained from rabbits and humans after unilateral nephrectomy (uni sera) compared with sera obtained preoperatively (control sera) significantly stimulate 3H-thymidine incorporation into the DNA of cultured renal tissue from the respective species. In contrast, rabbit liver cells in culture are not stimulated by the uni sera compared with control sera obtained from rabbits. Mouse epidermal growth factor (EGF) added to tissue cultures significantly stimulates both kidney and liver cells of rabbits and kidney cells of humans. Antiserum against EGF overcomes, at least to some extent, the enhancing effect of EGF under all circumstances, but does not influence the stimulatory ability of uni serum obtained from rabbit and human kidney cells from the respective species. In addition, the activity of EGF was not different in the presence of uni and control sera. This study corroborates the presence of renotropic activity in the sera of rabbits and humans after removal of functioning renal mass and shows that this activity is not derived from EGF, nor does it work by potentiating some aspect of the EGF system.

Important aspects concerning evaluation of renal function and blood pressure. Kinins, prostaglandins, lead

The kallikrein-kinin and prostaglandin-thromboxane-leukotriene systems and the body lead burden all influence renal function and systemic blood pressure to some extent. Because these systems may become generally accepted as more important in assessing renal function and blood pressure in the future, a brief overview of each has been given.

Antibody reactivity with HBLV (HHV-6) in U.S. populations

500 sera representing healthy blood donors and a random representation of the U.S. population collected 10 years ago were screened by ELISA for antibody reactivity with purified, disrupted HBLV virions. In each group, the ELISA results were normally distributed with no evidence of bimodality. All sera were subsequently retested after preincubation of each with well-characterized preparations of disrupted HSB-2 cells or HBLV-infected HSB-2 cells. Sera showing significant levels of HBLV-specific neutralization (50% or more) were found in Minneapolis, Kansas City, and in a random population survey (81, 88 and 97% of donors, respectively). Mean ELISA test values were the same for all groups and for males and females within the same group. Sera from these normal donors reacted preferentially with viral antigens of 120 and 58 kDa by Western blot. In a hospital-based prevalence study, frequent IgM and IgG seroconversions were apparent among infants less than 1 year old, and mean ELISA test values reached the adult level before school age. Antigen preparations used in blocking experiments showed no competitive cross-reactivity with antisera against EBV, CMV, HSV, VZV, HIV, or adenovirus type 2 at levels which reduced antibody binding to HBLV by more than 90%. Antibody cross-reactivities towards HBLV and other human herpesviruses were assessed by cross-correlation of viral antibody titers against all of the viruses and by cross-absorptions of antisera against the other viruses with HBLV. In these experiments no antibody cross-reactivity between HBLV and other human herpesviruses were detected. The significance of these findings with respect to health/disease status is presently unknown. Further seroepidemiologic studies of quantitative levels of HBLV antibody reactivity to measure the age of primary infection and progressive changes in healthy and selected disease populations are needed to determine the risk of disease associated with HBLV infection.

Human B-lymphotropic virus (human herpesvirus-6)

Human B-lymphotropic virus (HBLV), also known as human herpesvirus-6 (HHV-6) was first isolated in 1986 from AIDS patients and patients with other lymphoproliferative disorders. HBLV is distinct from known human herpesviruses, biologically, immunologically and by molecular analysis. HBLV can infect and replicate in fresh and established lines of hemopoietic cells and cells of neural origin, suggesting wide tropism. The prevalence of HBLV antibody in the normal population was 26% though clear differences between different populations were observed. The prevalence of HBLV antibody an elevated antibody titer was higher in sera from certain malignancies, Sjögren's syndrome and sarcoidosis. Antibody to HBLV was also elevated in AIDS patients and patients with chronic fatigue syndrome. HBLV-DNA was detected in some B-cell lymphomas. The broad in vitro tropism, combined with immunological and molecular evidence of HBLV infection in individuals raise the question of the pathogenicity of this virus in some diseases. Because in vitro co-infection of CD4 cells by HBLV and HIV leads to enhanced degeneration, this raises the possibility that infection in AIDS patients by both viruses can aggravate the HIV-induced immunodeficiency. Specific reagents and immunological and molecular assays are currently being investigated, which will aid in virus detection in cells from patients, and in elucidating the possible pathogenesis of HBLV.