Indoor air pollution from solid fuels and risk of upper aerodigestive tract cancers in central and eastern Europe.

BACKGROUND: Indoor air pollution from solid fuels is a potentially important risk factor for cancer, yet data on cancers from organs other than the lung are scarce. We investigated if indoor air pollution from coal and wood are risk factors for additional cancers, particularly that of the upper aerodigestive tract (oral cavity, larynx, pharynx and esophagus) in the high-risk areas of central and eastern Europe. METHODS: We used data from multi-center hospital-based case-control study of 1065 histologically confirmed upper aerodigestive tract cancer cases and 1346 controls. Standardized questionnaires were used to collect information on residential fuel use for cooking and heating. Using unconditional logistic regression, we calculated odds ratios (ORs) and 95% confidence intervals (95% CIs) for upper aerodigestive tract cancer risk after adjusting for potential confounders. RESULTS: Lifelong wood use was associated with pharyngeal and esophageal (OR 4.05, 95% CI: 1.30-12.68 and OR 2.71, 95% CI: 1.21-6.10, respectively). We observed an exposure-response relationship between duration of wood use and risk of pharyngeal cancer among those who had never used coal (P(trend)=0.04), ruling out the possibility of residual confounding by coal. Similarly, we observed an increased risk of laryngeal cancers and head & neck cancers among those who always used coal, with a noted exposure-response relationship (P(trend)<0.01). CONCLUSIONS: Our results suggest a possible role of indoor air pollution from solid fuel use in head and neck carcinogenesis in the high risk area of central and eastern Europe.

Genomic copy number alterations in clear cell renal carcinoma: associations with case characteristics and mechanisms of VHL gene inactivation.

Array comparative genomic hybridization was used to identify copy number alterations in clear cell renal cell carcinoma (ccRCC) patient tumors to identify associations with patient/clinical characteristics. Of 763 ccRCC patients, 412 (54%) provided frozen biopsies. Clones were analyzed for significant copy number differences, adjusting for multiple comparisons and covariates in multivariate analyses. Frequent alterations included losses on: 3p (92.2%), 14q (46.8%), 8p (38.1%), 4q (35.4%), 9p (32.3%), 9q (31.8%), 6q (30.8%), 3q (29.4%), 10q (25.7%), 13q (24.5%), 1p (23.5%) and gains on 5q (60.2%), 7q (39.6%), 7p (30.6%), 5p (26.5%), 20q (25.5%), 12q (24.8%), 12p (22.8%). Stage and grade were associated with 1p, 9p, 9q, 13q and 14q loss and 12q gain. Males had more alterations compared with females, independent of stage and grade. Significant differences in the number/types of alterations were observed by family cancer history, age at diagnosis and smoking status. Von Hippel-Lindau (VHL) gene inactivation was associated with 3p loss (P

Occupational exposure to dusts and risk of renal cell carcinoma.

BACKGROUND: Occupational exposures to dusts have generally been examined in relation to cancers of the respiratory system and have rarely been examined in relation to other cancers, such as renal cell carcinoma (RCC). Although previous epidemiological studies, though few, have shown certain dusts, such as asbestos, to increase renal cancer risk, the potential for other occupational dust exposures to cause kidney damage and/or cancer may exist. We investigated whether asbestos, as well as 20 other occupational dust exposures, were associated with RCC risk in a large European, multi-center, hospital-based renal case-control study. METHODS: General occupational histories and job-specific questionnaires were reviewed by occupational hygienists for subject-specific information. Odds ratios (ORs) and 95% confidence intervals (95% CIs) between RCC risk and exposures were calculated using unconditional logistic regression. RESULTS: Among participants ever exposed to dusts, significant associations were observed for glass fibres (OR: 2.1; 95% CI: 1.1-3.9), mineral wool fibres (OR: 2.5; 95% CI: 1.2-5.1), and brick dust (OR: 1.5; 95% CI: 1.0-2.4). Significant trends were also observed with exposure duration and cumulative exposure. No association between RCC risk and asbestos exposure was observed. CONCLUSION: Results suggest that increased RCC risk may be associated with occupational exposure to specific types of dusts. Additional studies are needed to replicate and extend findings.

TP53, EGFR, and KRAS mutations in relation to VHL inactivation and lifestyle risk factors in renal-cell carcinoma from central and eastern Europe.

Renal-cell carcinomas (RCC) are frequent in central and eastern Europe and the reasons remain unclear. Molecular mechanisms, except for VHL, have not been much investigated. We analysed 361 RCCs (334 clear-cell carcinomas) from a multi-centre case-control study for mutations in TP53 (exons 5-9 in the whole series and exons 4 and 10 in a pilot subset of 60 tumours) and a pilot 50 tumours for mutations in EGFR (exons 18-21) or KRAS (codon 12) in relation to VHL status. TP53 mutations were detected in 4% of clear-cell cases, independently of VHL mutations. In non-clear-cell carcinomas, they were detected in 11% of VHL-wild-type tumours and in 0% of tumours with VHL functional mutations. No mutations were found in EGFR or KRAS. We conclude that mutations in TP53, KRAS, or EGFR are not major contributors to the RCC development even in the absence of VHL inactivation. The prevalence of TP53 mutations in relation to VHL status may differ between clear-cell and other renal carcinomas.

Vitamin d pathway genes, diet, and risk of renal cell carcinoma.

Mediated by binding to the high-affinity vitamin D receptor (VDR), vitamin D forms a heterodimer complex with the retinoid-X-receptor (RXR). Variation in both genes has been shown to modify renal cell carcinoma (RCC) risk. Therefore, we investigated whether VDR and RXRA polymorphisms modify associations between RCC risk and frequency of dietary intake of vitamin D and calcium rich foods, and occupational ultraviolet exposure among 777 RCC case and 1035 controls from Central and Eastern Europe. A positive association was observed in this population between increasing dietary intake frequency of yogurt, while an inverse association was observed with egg intake frequency. RXRA polymorphisms, located 3' of the coding sequence, modified associations between specific vitamin D rich foods and RCC risk, while RXRA polymorphisms, located in introns 1 and 4, modified associations with specific calcium rich foods. Results suggest that variants in the RXRA gene modified the associations observed between RCC risk and calcium and vitamin D intake.

Association of common genetic variants with colorectal cancer risk in a Romanian sample.

Recently, several genome-wide association studies identified and validated loci at which common genetic variants influence the risk of colorectal cancer. We aimed to test the association between eight SNPs and colorectal cancer in a Romanian case-control sample. We genotyped rs10795668, rs16892766, rs3802842, rs4444235, rs4779584, rs4939827, rs6983267, and rs9929218 and we statistically tested the association with the disease. Five SNPs (rs6983267, rs4939827, rs3802842, rs4444235, rs10795668) showed an association with colon and rectal cancer. Three of them proved to be statistically significant: rs6983267 and rs4939827 risk alleles were significantly associated with rectal cancers (p = 0.031 and p = 0.004 for homozygous, p = 0.002 and p = 0.005 for heterozygous). For rs3802842 we found a greater risk for colon than rectal cancer with an OR of 2.26 (CI = 1.04-5.88, p = 0.040) for the dominant model. The rs4444235 confirmed the risk for both homozygous and heterozygous carriers, with the greatest ORs of 1.49 (CI = 0.61-3.61) for heterozygote. For rs10795668 we found an increased risk for rectum cancer vs. controls with an OR of 1.46 (CI = 0.66-3.21), and for rectum cancer vs. colon cancer (OR = 2.19; CI = 0.87-5.55). This is the first Romanian study that confirms previously-identified associations with colorectal cancer risk for five out of eight SNPs investigated and underlines the necessity of extensive replication using larger samples.

Occupation and renal cell cancer in Central and Eastern Europe.

OBJECTIVE: Central and Eastern Europe has among the highest rates of renal cell cancer worldwide. Few studies have been conducted in these areas to investigate the possible role of occupational exposures in renal cell cancer aetiology. The purpose of this study was to examine the association of renal cell cancer with employment in specific occupations and industries. METHODS: From 1999 to 2003, we conducted a hospital-based case-control study in seven areas of the Czech Republic, Poland, Romania and Russia. A detailed occupational history was collected from renal cell cancer cases and controls, together with information on potential confounders. Odds ratios (ORs) and 95% CI of cancer risk were calculated for having ever been employed in selected jobs and industries, with follow-up analyses examining duration of employment. RESULTS: A total of 992 histologically confirmed incident renal cell cancer cases and 1459 controls were included in the analysis. An increased risk of renal cell cancer was observed for workers in agricultural labour and animal husbandry (OR 1.43; 95% CI 1.05 to 1.93), particularly among women employed as general farm workers (OR 2.73; 95% CI 1.05 to 7.13). Risk gradients for agricultural work increased with longer employment. An overall increased risk of renal cell cancer was seen among architects and engineers (OR 1.89; 95% CI 1.35 to 2.65), and mechanical engineers (OR 1.71; 95% CI 1.03 to 2.84). CONCLUSIONS: Our data suggest an association between renal cell cancer and agricultural work, particularly among female workers.

Tobacco smoking, body mass index, hypertension, and kidney cancer risk in central and eastern Europe.

In a case-control study of kidney cancer in four central European countries, with 1097 incident cases and 1476 controls, we found an increased risk for self-reported hypertension and for obesity. Additional unknown risk factors are likely to be responsible for the high rates of kidney cancer in this region.

Renal cell carcinoma, occupational pesticide exposure and modification by glutathione S-transferase polymorphisms.

This study investigated associations between occupational pesticide exposure and renal cell carcinoma (RCC) risk. To follow-up on a previous report by Buzio et al., we also considered whether this association could be modified by glutathione S-transferase M1 and T1 (GSTM1 and GSTT1) genotypes. About 1097 RCC cases and 1476 controls from Central and Eastern Europe were interviewed to collect data on lifetime occupational histories. Occupational information for jobs held for at least 12 months duration was coded for pesticide exposures and assessed for frequency and intensity of exposure. GSTM1 and GSTT1 gene deletions were analyzed using TaqMan assays. A significant increase in RCC risk was observed among subjects ever exposed to pesticides [odds ratio (OR): 1.60; 95% confidence interval (CI): 1.00-2.55]. After stratification by genotypes, increased risk was observed among exposed subjects with at least one GSTM1 active allele (OR: 4.00; 95% CI: 1.55-10.33) but not among exposed subjects with two GSTM1 inactive alleles compared with unexposed subjects with two inactive alleles (P-interaction: 0.04). Risk was highest among exposed subjects with both GSTM1 and GSTT1 active genotypes (OR: 6.47; 95% CI: 1.82-23.00; P-interaction: 0.02) compared with unexposed subjects with at least one GSTM1 or T1 inactive genotype. In the largest RCC case-control study with genotype information conducted to date, we observed that risk associated with pesticide exposure was exclusive to individuals with active GSTM1/T1 genotypes. These findings further support the hypothesis that glutathione S-transferase polymorphisms can modify RCC risk associated with occupational pesticide exposure.

Dietary risk factors for squamous cell carcinoma of the upper aerodigestive tract in central and eastern Europe.

OBJECTIVE: The incidence of squamous cell carcinoma of upper aerodigestive tract (UADT: oral cavity, pharynx, larynx, and esophagus) has been increasing in central and eastern European countries. We investigated the relationship between diet and UADT cancers in these high risk areas. METHODS: We used data from hospital-based case-control study of 948 UADT cancer cases and 1,228 controls conducted in Romania, Hungary, Poland, Russia, Slovakia, and Czech Republic. Standardized questionnaire were used to collect information on 23 different food items, along with alcohol and tobacco consumptions. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for the UADT cancers after adjusting for center, age, sex, tobacco & alcohol intake, and other food groups. RESULTS: Consumption of dairy product was negatively associated with selected UADT cancers: larynx (OR: 0.38, CI: 0.23-0.62) and esophagus (OR: 0.55, CI: 0.33-0.93). While consumption of yellow/orange vegetables were inversely associated with oral/pharyngeal and laryngeal cancer (OR: 0.53, CI: 0.35-0.81 and OR: 0.62, CI: 0.38-1.00, respectively), preserved vegetable was positively associated with oral/pharyngeal and laryngeal cancer risk (p (trend) < 0.01 for both). CONCLUSION: Specific dietary components may play a role in the development of UADT cancers in the high-risk region of central and eastern Europe.

Vitamin D receptor polymorphisms and renal cancer risk in Central and Eastern Europe.

Previous studies investigated the role of vitamin D intake and cancer risk. The kidney is a major organ for vitamin D metabolism, activity, and calcium homeostasis; therefore, it was hypothesized that dietary vitamin D intake and polymorphisms in the vitamin D receptor (VDR) gene may modify renal cell carcinoma (RCC) risk. Three common VDR gene polymorphisms (BsmI, FokI, TaqI) were evaluated among 925 RCC cases and 1192 controls enrolled in a hospital-based case-control study conducted in Central and Eastern Europe. Overall associations with RCC risk were not observed; however, subgroup analyses revealed associations after stratification by median age of diagnosis and family history of cancer. Among subjects over 60 yr, reduced risks were observed among carriers of the f alleles in the FokI single-nucleotide polymorphism (SNP) (odds ratio [OR] = 0.61 for Ff and OR = 0.74 for ff genotypes) compared to subjects with the FF genotype (P trend = 0.04; P interaction = 0.004). Subjects with the BB BsmI genotype and a positive family history of cancer had lower risk compared to subjects with the bb allele (OR = 0.60; 95% CI: 0.33-1.1; P trend = 0.05). Genotype associations with these subgroups were not modified when dietary sources of vitamin D or calcium were considered. Additional studies of genetic variation in the VDR gene are warranted.

Glutathione S-transferase polymorphisms, cruciferous vegetable intake and cancer risk in the Central and Eastern European Kidney Cancer Study.

High consumption of cruciferous vegetables has been associated with reduced kidney cancer risk in many studies. Isothiocyanates, thought to be responsible for the chemopreventive properties of this food group, are conjugated to glutathione by glutathione S-transferases (GSTs) before urinary excretion. Modification of this relationship by host genetic factors is unknown. We investigated cruciferous vegetable intake in 1097 cases and 1555 controls enrolled in a multicentric case-control study from the Czech Republic, Poland, Romania and Russia. To assess possible gene-diet interactions, genotyped cases (N = 925) and controls (N = 1247) for selected functional or non-synonymous polymorphisms including the GSTM1 deletion, GSTM3 3 bp deletion (IVS6 + 22-AGG) and V224I G>A substitution, GSTT1 deletion and the GSTP1 I105V A>G substitution. The odds ratio (OR) for low (less than once per month) versus high (at least once per week) intake of cruciferous vegetables was 1.29 [95% confidence interval (CI): 1.02-1.62; P-trend = 0.03]. When low intake of cruciferous vegetables (less than once per month) was stratified by GST genotype, higher kidney cancer risks were observed among individuals with the GSTT1 null (OR = 1.86; 95% CI: 1.07-3.23; P-interaction = 0.05) or with both GSTM1/T1 null genotypes (OR = 2.49; 95% CI: 1.08-5.77; P-interaction = 0.05). These data provide additional evidence for the role of cruciferous vegetables in cancer prevention among individuals with common, functional genetic polymorphisms.

Tubular carcinoma of the breast: a population-based study of nodal metastases at presentation and of patterns of relapse.

Tubular carcinoma of the breast (TCB) is a recognized histologic variant of infiltrating ductal carcinoma (IDC) and has been considered to have a comparatively favorable prognosis. However, previous studies have been based on small numbers of cases, some pure TCB and some mixed histology, or have not employed an appropriate comparison group. In this study 171 pure TCB cases and a comparison group of 386 cases with grade I (well differentiated) IDC were identified in a population-based database maintained by the British Columbia Cancer Agency (BCCA). The proportion of cases with axillary nodal involvement at presentation was lower in TCB cases than in the grade I IDC comparison group (12.9% and 23.9%, respectively; p < 0.05). Low-risk tumors (T1 and without vascular lymphatic or perineural invasion) were more prevalent in the TCB patients than in the grade I IDC patients (66.7% and 60.0%; p < 0.05). Low-risk TCB cases had a significantly lower rate of nodal metastases at presentation than low-risk grade I IDC cases (7.0% and 13.2%; p < 0.05). Kaplan-Meier and log-rank analyses indicated a statistically significantly lower rate of local recurrence in TCB cases than among IDC cases (p < 0.05) and a trend toward a lower rate of systemic relapse in TCB cases (p = 0.07). However, no difference in disease-specific survival was observed between TCB cases and grade I IDC comparisons. We conclude that the biologic behavior of TCB was more favorable than that of a comparison group of IDC cases. In view of the low incidence of axillary node metastases at presentation in the low-risk TCB subset (7%), axillary dissection may be omitted as part of the initial surgical management in these patients.

Health system costs of metastatic breast cancer.

To assess the costs of treating patients with incurable breast cancer, all health system costs during the interval from diagnosis of first recurrence or metastasis until death for 75 female subjects randomly selected from those known to have died of breast cancer in British Columbia, Canada between July 1, 1995 and December 31, 1996, were identified. Costs were determined from several databases within the British Columbia (BC) Ministry of Health, as well as from BC Cancer Agency patient charts. The mean total cost to the health system was CDN $36,474.33 (95% confidence interval $29,752-$43,196) per subject. The mean costs were highest for the youngest age group and lowest for the middle age group, but these only differed by $2,300. Inpatient costs accounted for the greatest proportion of the total, over 50% in all age groups. This data may be valuable in assessing the cost-effectiveness of interventions that are known to affect mortality due to breast cancer.

Diagnosis of metachronous contralateral breast cancer.

The purpose of this study was to compare the characteristics of primary breast cancers (PBCs) and metachronous contralateral breast cancers (MCBCs). Between 1984 and 1996, 236 women treated with curative intent for PBC who developed a MCBC >6 months after initial diagnosis (without previous evidence of distant metastases) were retrospectively evaluated for clinical and pathologic characteristics and method of diagnosis of their tumors. There were more noninvasive cancers among the MCBCs than the PBCs (11.4% and 5.1%, respectively, p < 0.02). Among the invasive cancers, the mean size of the MCBCs was smaller than the PBCs (1.94 versus 2.55 cm, p < 0.001). MCBCs were more likely than PBCs to be mammographically detected (46.2% versus 19.9%, p < 0.001). Tumor size was correlated with the method of diagnosis. The mean tumor size was 1.39, 2.02, and 2.69 cm for mammogram-, physician-, and patient-detected tumors, respectively. Among patients having axillary lymph node dissections, mammogram- and physician-detected tumors were less likely to have lymph node metastases than patient-detected tumors (22.0% versus 41.2%, p < 0.005). Regular follow-up of breast cancer patients diagnoses MCBCs when they are smaller and less likely to have nodal metastases than PBCs mainly because of early mammographic detection.

Relationship between tumor location and relapse in 6,781 women with early invasive breast cancer.

PURPOSE: To explore the independent prognostic impact of medial hemisphere tumor location in early breast cancer. PATIENTS AND METHODS: A comprehensive database was used to review patients referred to the British Columbia Cancer Agency from 1989 to 1995 with early breast cancer. Patients were grouped according to relapse risk (high or nonhigh) and adjuvant systemic therapy received. Multiple regression analysis was used to determine whether the significance of primary tumor location (medial v lateral hemisphere) was independent of known prognostic factors and treatment. RESULTS: In the adjuvant systemic therapy groups, medial location was associated with a 50% excess risk of systemic relapse and breast cancer death compared with lateral location. Five-year systemic disease-free survival rates were 66.3% and 74.2% for high-risk medial and lateral lesions, respectively (P <.005). Corresponding 5-year disease-specific survival rates were 75.7% and 80.8%, respectively (P <.03). No significant differences were observed between medial and lateral location for low-risk disease regardless of adjuvant therapy or for high-risk disease with no adjuvant therapy. Local recurrence rates were similar for all risk and therapy groups. CONCLUSION: The two-fold risk of relapse and breast cancer death associated with high-risk medial breast tumors may be due to occult spread to internal mammary nodes (IMNs). Enhanced local control, such as with irradiation of the IMN chain, may be one way to reduce the excess risk. Ongoing randomized controlled trials may provide prospective answers to the question of the optimal volume of radiotherapy.

A decision analysis of the effect of avoiding axillary lymph node dissection in low risk women with invasive breast carcinoma.

BACKGROUND: Evidence that avoiding axillary lymph node dissection (AxD) strikes an appropriate balance between morbidity and recurrence risk in patients with invasive breast carcinoma generally is anecdotal and without a formally quantified basis. The current study presents a decision analysis of the difference in 5-year disease free survival (DFS) rate between treatment scenarios with and without routine AxD. METHODS: To derive quantitative estimates of the effect of avoiding AxD on 5-year DFS, the authors examined outcomes for women undergoing 2 treatment scenarios: AxD or no AxD with adjuvant therapy decisions based on risk factors in the primary tumor. Eligible patients belonged to 2 lymph node metastases risk groups: low (patients without palpable lymph nodes and lymphatic or vascular invasion [LVI] negative tumors < or = 0.5 cm in greatest dimension) and moderate (patients with mammographically detected, LVI negative tumors, between 0.6-2.0 cm in greatest dimension or patients with palpable LVI negative tumors between 0.6-1.0 cm in greatest dimension with nonpalpable lymph nodes). Along with observed data regarding treatment and recurrence, the authors employed estimates of the efficacy of chemotherapy, tamoxifen, and regional radiation therapy derived from published randomized trials to estimate the 5-year DFS rate for treatment scenarios with and without AxD. RESULTS: Patients in the low risk group had a 5% risk of lymph node metastases. In these women, eliminating AxD and treating no patients with chemotherapy and/or tamoxifen resulted in a < 1% decrease in the 5-year DFS rate. Patients in the moderate risk group had a 10% risk of lymph node metastases. Eliminating AxD and treating only those women with Grade 3 tumors > 1 cm in greatest dimension with chemotherapy and/or tamoxifen resulted in a 1.8% decrease in the 5-year DFS rate. However, if all patients in this group were treated with chemotherapy and/or tamoxifen and no AxD, the 5-year DFS rate increased by 2.7%. CONCLUSIONS: In patients with a low risk of lymph node metastases, it was estimated that eliminating AxD may result in only minimal changes in the estimated 5-year DFS rate.

Effect of time interval between breast-conserving surgery and radiation therapy on ipsilateral breast recurrence.

PURPOSE: To examine the effect of the time interval (interval) between breast-conserving surgery (BCS) and the start of radiation therapy (RT) on the subsequent risk of ipsilateral breast cancer recurrence (IBR). METHODS AND MATERIALS: We reviewed interval and a number of prognostic and treatment factors among 1,962 women treated with BCS and RT for invasive breast cancer diagnosed between January 1, 1989 and December 31, 1993 in British Columbia, Canada. Subjects were female, less than 90 years old at diagnosis, not treated with chemotherapy, not stage T4 or M1, and had survived more than 30 days from diagnosis. The cumulative incidence of IBR was estimated in four interval groups: 0-5, 6-8, 9-12, and 13+ weeks. Only 23 women had an interval of greater than 20 weeks between BCS and start of RT. To assess whether an imbalance of prognostic and treatment factors could be obscuring real differences between the interval groups, Cox proportional hazards regression analyses were conducted. RESULTS: Median follow-up was 71 months. The crude incidence of IBR for the entire sample was 3.9%. The cumulative incidence of IBR in the 6-8, 9-12, and 13+ week groups was not statistically significantly different from the cumulative incidence of IBR in the 0-5 week group. Multivariate analyses demonstrated that patients not using tamoxifen p = 0.027) and those with grade 3 histology (p = 0.003) were more likely to recur in the breast. Interval between BCS and RT was not a statistically significant predictor of breast recurrence when entered into a model incorporating tamoxifen use and tumor grade (0-5 vs. 6-8 weeks, p = 0.872; 0-5 vs. 9-12 weeks, p = 0.665; 0-5 vs. 13+ weeks, p = 0.573). CONCLUSIONS: We found no univariate or multivariate difference in ipsilateral breast cancer recurrence between intervals of 0 to 20 weeks from breast conserving surgery to start of radiation therapy, in a population-based, low risk group of women not receiving adjuvant chemotherapy, after controlling for other factors important in predicting ipsilateral breast cancer recurrence.

Prognosis, treatment, and recurrence of breast cancer for women attending or not attending the Screening Mammography Program of British Columbia.

Breast cancer screening programs have been initiated in many countries in the past decade. To determine the impact of the Screening Mammography Program of British Columbia (SMPBC), disease and treatment outcomes for women with breast cancer diagnosed in BC between 1989 and 1996 were compared on the basis of attendance at the SMPBC. An SMPBC attender was a women diagnosed with breast cancer within three years of an SMPBC screen, regardless whether the cancer was detected as a result of that screen. Of the 13,636 women aged 40-89 years diagnosed with breast cancer in BC during the study period, 2,647 (19.4%) were SMPBC attenders. 73.5% of SMPBC attenders (N = 1,946) and 74.2% of non-attenders (N = 8,149) were referred to the BC Cancer Agency and had pathology, staging, treatment, and outcome information available. SMPBC attenders compared with non-attenders were more likely to have in situ disease alone, and those with invasive cancers had smaller tumors which were less likely to have grade III histology and less likely to have spread to axillary lymph nodes (all P < 0.001). SMPBC attenders were more likely to be treated with breast conservation and less likely to receive adjuvant chemotherapy or tamoxifen (P < 0.001). Log-rank tests showed local (P = 0.017), distant (P < 0.001), and overall (P < 0.001) disease-free survival were better for SMPBC attenders. These favorable surrogate endpoints suggest that the benefits of breast screening as demonstrated by randomized trials can be translated into community practice by an organized breast screening program.

Screening Mammography Program of British Columbia: pattern of use and health care system costs.

BACKGROUND: The use of mammography for screening asymptomatic women has increased dramatically in the past decade. This report describes the changes that have occurred in the use of bilateral mammography in British Columbia since the provincial breast cancer screening program began in 1988. METHODS: Using province-wide databases from both the breast cancer screening program and the provincial health insurance plan in BC, the authors determined the number and costs of bilateral mammography services for women aged 40 years or older between Apr. 1, 1986, and Mar. 31, 1997. Unilateral mammography was excluded because it is used for investigating symptomatic disease and screening abnormalities, and for follow-up of women who have undergone mastectomy for cancer. RESULTS: As the provincial breast cancer screening program expanded from 1 site in 1988 to 23 in 1997, it provided an increasing proportion of the bilateral mammographic examinations carried out each year in BC. In fiscal year 1996/97, 65% of bilateral mammographic examinations were performed through the screening program. The cost per examination within the screening program dropped as volume increased. Thirty percent more bilateral mammography examinations were done in 1996/97 than in 1991/92, but health care system expenditures for these services increased by only 4% during the same period. In calendar year 1996, 21% of new breast cancers were diagnosed as a result of a screening program visit. INTERPRETATION: Substantial increases in health care expenditures have been avoided by shifting bilateral mammography services to the provincial screening program, which has a lower cost per screening visit.