Cancer incidence, mortality, and stage at diagnosis in First Nations living in Manitoba.

BACKGROUND: In the present study, we examined breast (bca) and colorectal cancer (crc) incidence and mortality and stage at diagnosis for First Nations (fn) individuals and all other Manitobans (aoms). METHODS: Several population-based databases were linked to determine ethnicity and to calculate age-standardized incidence and mortality rates. Logistic regression was used to compare bca and crc stage at diagnosis. RESULTS: From 1984-1988 to 2004-2008, the incidence of bca increased for fn and aom women. Breast cancer mortality increased for fn women and decreased for aom women. First Nations women were significantly more likely than aom women to be diagnosed at stages iii-iv than at stage i [odds ratio (or) for women ≤50 years of age: 3.11; 95% confidence limits (cl): 1.20, 8.06; or for women 50-69 years of age: 1.72; 95% cl: 1.03, 2.88). The incidence and mortality of crc increased for fn individuals, but decreased for aoms. First Nations status was not significantly associated with crc stage at diagnosis (or for stages i-ii compared with stages iii-iv: 0.98; 95% cl: 0.68, 1.41; or for stages i-iii compared with stage iv: 0.91; 95% cl: 0.59, 1.40). CONCLUSIONS: Our results underscore the need for improved cancer screening participation and targeted initiatives that emphasis collaboration with fn communities to reduce barriers to screening and to promote healthy lifestyles.

Type-specific human papillomavirus infections and Pap test findings in Inuit and non-Inuit women in Nunavut, Canada.

OBJECTIVE: To determine the prevalence and distribution of type-specific human papillomavirus (HPV) infections and their association with cytological outcomes in women living in the Canadian territory of Nunavut. METHODS: Surveillance of type-specific HPV infection was conducted. Cervical specimens of all Inuit, First Nations and non-Aboriginal women in Nunavut who presented for a Pap test in any clinical setting between January 2008 and March 2009 were tested for HPV infection. The association between high-grade cervical lesions and HPV type was also examined. RESULTS: HPV results were available for 4,043 individual women (13 to 77 years). Of those with known ethnicity (N=4,033), 89.2% were Inuit, 0.4% were First Nations and 10.4% were non-Aboriginal. First Nations women were included in all analyses except those making comparisons by ethnicity, due to the small number of individuals in this group. Overall, 29.9% of women were found to be infected with HPV (any type) and 19.9% with any high-risk HPV (type 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58 or 59). Most often, women were infected with HPV 16 (6.4%) followed by HPV 31 (3.1%). There were no statistically significant differences between Inuit and non-Aboriginal (reference group) women 20 years of age and older regarding the prevalence of any HPV (odds ratios (OR): 1.19, 95% confidence intervals (CI): 0.92-1.54), high-risk HPV (OR: 1.06, 95% CI: 0.78-1.44) or HPV 16 and 18 (OR: 0.81, 95% CI: 0.51-1.27). HPV 31 was the only type that was significantly more frequent among Inuit than non-Aboriginal women (OR: 3.95, 95% CI: 1.24-12.54). There was no difference in the overall occurrence of cervical abnormalities between non-Aboriginal and Inuit women (p-value = 0.17). HPV 16 was strongly associated with cervical dysplasia, being present in 50.9% of specimens with a high-grade lesion. CONCLUSION: HPV is a significant public health issue in the territory of Nunavut. The findings presented in this article are similar to those in other studies among Inuit women, with prevalence of HPV being higher than in studies conducted among non-Inuit women in other regions of Canada. These results provide a baseline of HPV prevalence that precedes the introduction of the Nunavut HPV Immunization Program in 2010 and will allow for future evaluation. The high prevalence of HPV infection among women living in Nunavut can be reduced through immunization and associated high-grade cervical abnormalities mitigated by regular cervical screening.

Distribution of human papillomavirus types, cervical cancer screening history, and risk factors for infection in Manitoba.

OBJECTIVES: We conducted a study to investigate the prevalence of human papillomavirus (HPV) infections in an opportunistic sample of women in Manitoba, Canada. We inquired about risk factors associated with HPV infections and linked the HPV typing results with the cervical cancer screening history of the participants. METHODS: The study population included 592 women attending Papanicolaou (Pap) test clinics. After signing a consent form, participants were given a self-administered questionnaire on risk factors and received a conventional Pap test. Residual cells from the Pap tests were collected and sent for HPV typing. RESULTS: The mean age of the population was 43 years. A total of 115 participants (19.4%) had an HPV infection, 89 of whom had a normal Pap test. Of those who were HPV-positive, 61 (10.3%) had high-risk (Group 1) HPV. HPV-16 was the most prevalent type (15/115: 13.0% of infections). The most consistent risk factors for HPV infection were young age, Aboriginal ethnicity, higher lifetime number of sexual partners and higher number of sexual partners in the previous year. CONCLUSION: The prevalence of HPV types in Manitoba is consistent with the distributions reported in other jurisdictions. These data provide baseline information on type-specific HPV prevalence in an unvaccinated population and can be useful in evaluating the effectiveness of the HPV immunization program. An added benefit is in the validation of a proof of concept which links a population-based Pap registry to laboratory test results and a risk behaviour survey to assess early and late outcomes of HPV infection. This methodology could be applied to other jurisdictions across Canada where such capacities exist.

High incidence of chronic lymphocytic leukemia (CLL) diagnosed by immunophenotyping: a population-based Canadian cohort.

Incidence and outcomes of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) are not well established at the population level, especially since the widespread use of immunophenotyping. We studied the epidemiology of CLL in Manitoba (Canada) by combining data from a centralized flow cytometry facility and the provincial cancer registry for the period 1998-2003. Of 616 cases identified, 27% of patients identified by flow cytometry were not on the cancer registry. The age-adjusted incidence of 7.99/100,000 is substantially higher than the reported incidence in registry reports. We also noted differences in relative survival based on age and gender.

Incidence of right-sided colorectal cancer after breast cancer: a population-based study.

OBJECTIVES: Estrogen levels, which are involved in the development of breast cancer, may also be responsible for a higher incidence of right-sided colorectal neoplasia in women. Our objective was to determine the incidence of right-sided colorectal cancer (CRC) after the diagnosis of breast cancer. METHODS: All cases of breast cancers diagnosed between 1956 and 2006 were identified from the Manitoba Cancer Registry (MCR) and followed up until the diagnosis of any invasive cancer, death, migration out of the province, or 31 December 2006. Standardized incidence ratios (SIRs) for all CRC and right-sided CRC (cecum, ascending colon, and hepatic flexure) were calculated to compare the observed CRC incidence with that expected in the general population. Stratified analysis was performed to determine the risk at different follow-up time intervals, age at breast cancer diagnosis, and for tamoxifen use. RESULTS: There were 23,377 cases of breast cancer diagnosed between 1956 and 2006 with a total follow-up of 221,364 patient-years. The SIR for all CRC was 0.96 (95% confidence interval (CI) 0.87-1.06) and for right-sided CRC it was 1.02 (95% CI 0.87-1.20). The SIRs remained close to unity at different time intervals, for different age groups, and in analysis restricted to more recent years (1985-2006). Tamoxifen use did not alter the risk of all CRC (SIR 1.22; 95% CI 0.92-1.62) or right-sided CRC (SIR 0.90; 95% CI 0.48-1.54). CONCLUSIONS: There is no increase in the overall risk for CRC or for right-sided CRC after the diagnosis of breast cancer. CRC screening strategy for breast cancer survivors should be similar to that for the general population.

Survival and treatment trends of rectal cancer patients in a population with suboptimal local control.

AIM: To explore trends in rectal cancer survival in Manitoba, particularly in patients where local control was an issue. METHOD: Patients diagnosed with rectal or rectosigmoid adenocarcinoma from 1985 to 1999 were included. Demographic, treatment and mortality information were abstracted from the registry. Relative survival was examined for all patients for the periods 1985-1989, 1990-1994 and 1995-1999, and subsequently limited to those who underwent major surgery (Hartmann's, anterior, and abdominal perineal resection). RESULTS: Of the 2925 patients identified, 2163 (74%) had undergone a major surgery. Five-year relative survival was 46%, 54% and 53% for all patients for the three periods, respectively; major surgery results were 53%, 59% and 60%. Radiotherapy was used in 32% of cases in 1985-1989 and in 40% of cases in 1995-1999. Chemotherapy was used in 13% of cases in 1985-1989 and in 37% of cases in 1995-1999. CONCLUSION: Consistent with other studies, overall rectal cancer survival in Manitoba has improved since 1985. Better local control, as suggested in other studies, does not appear to be a major factor in that improvement. Future work should include review of the local control strategy in Manitoba and factors to explain the improved survival.

High rate of discordance between clinical and autopsy diagnoses in blood and marrow transplantation.

We analyzed autopsies performed in a Canadian blood and marrow transplantation (BMT) program. We aimed to assess variables that predict the performance of an autopsy, whether rates of autopsy are changing, and the rate of discordance between clinical and autopsy diagnoses. All deceased adult patients from January 1990 to December 2004 were reviewed. Autopsy rates were compared to a large teaching hospital. Of 476 myeloablative BMT patients, 225 died and 48 (27%) underwent autopsy. Autopsy was more likely in patients dying: <100 days post-BMT, in the intensive care unit, after allografting, and on weekends. Autopsy rates among BMT patients declined during the three time periods (1990-1994, 1995-1999, 2000-2004). The autopsy rate at the teaching hospital showed a similar downward temporal trend. Major and minor disagreements at autopsy were present in 16 (34%) and 14 (30%) of cases, respectively. There was no change in discordance rates over time. Thus, despite advances in diagnostic procedures, high levels of disagreement between clinical and autopsy diagnoses for BMT patients persist as autopsy rates decline. We recommend that the autopsy regains its role as a valuable investigation. This may become especially relevant in an era where patients with medical comorbidities are undergoing reduced-intensity BMT.