Male breast cancer: a population-based comparison with female breast cancer in Hong Kong, Southern China: 1997-2006.

BACKGROUND: Male breast cancer (MBC) is uncommon. As a result, there is limited availability of studies and reviews and even fewer reports from Asia. This is the largest population-based study to compare Chinese MBC patients with female patients during a 10-year period in Hong Kong, Southern China. METHODS: A retrospective review of medical records of 132 male and 8,118 female breast cancer patients between year 1997 and 2006 in Hong Kong was performed. Each MBC patient was matched with three female breast cancer patients for further analysis. Different characteristics, overall, breast-cancer specific, and disease-free survivals (DFS) were compared. RESULTS: Mean age at diagnosis of male and female patients was 64.5 and 52.7 years respectively. Male patients showed lower histological grade, overall stage, smaller tumor size, and more positive sensitivity in hormone receptors. They were more likely to die of causes other than breast cancer. Matched analysis found that the 5-year overall survival (OS), breast-cancer-specific mortality, and DFS for male and female patients were 78.7, 90.5, 90.5, and 77.9, 86.4, and 81.4 % respectively. Male patients had poorer OS at early overall stage but better breast-cancer-specific mortality rates at any age (p < 0.01). Male patients had a significant risk of dying due to any cause in the presence of distant relapse and had less risk of dying when tumor was ER-positive and HER2-positive. CONCLUSIONS: Chinese male breast cancer patients tend to have poorer OS but better breast-cancer-specific survival compared with their female counterparts.

Incidence, mortality, and survival trends of ovarian cancer in Hong Kong, 1997 to 2006: a population-based study.

OBJECTIVES: To assess the incidence and mortality of ovarian cancer, and the survival patterns of the invasive epithelial ovarian carcinoma in Hong Kong based on population-based cancer registry data. DESIGN: Historical cohort study. SETTING: Hong Kong. PATIENTS: All patients with ovarian cancer diagnosed between 1997 and 2006 were included. Patients eligible for survival analysis were followed up until 31 December 2007. MAIN OUTCOME MEASURES: Age-standardised incidence and mortality rates with their estimated annual percent changes were determined. Cumulative observed and relative survival rates were estimated using a period approach. RESULTS: During the study period, in Hong Kong there was a steadily increasing ovarian cancer incidence rate (1.4% annually) but a steadily decreasing mortality rate (1.9% annually). The improvement in mortality was mainly in the age-group of 50-69 years (4.7% annually). Invasive epithelial ovarian carcinoma accounted for 79.6% of the study cohort. The 2-year and 5-year relative survival rates were 75.8% and 63.1%, respectively. Those diagnosed in the period 2002 to 2006 had significantly better survival than those diagnosed in the period 1997 to 2001 (65.3% vs 60.7%; P=0.008); a significant improvement was evident for patients with stage II disease and in the age-group of 50-69 years. Multivariate analyses confirmed that age, histological subtype, FIGO stage, and the period of diagnosis were independent prognostic indicators of invasive epithelial ovarian carcinoma. CONCLUSION: In Hong Kong, invasive epithelial ovarian carcinoma showed an increasing incidence and an improving survival trend over the period 1997 to 2006. The survival data derived from this study provides a baseline from which to monitor the effectiveness of ovarian cancer treatment in Hong Kong.

Effectiveness of population-based colorectal cancer screening programme in down-staging.

BACKGROUND: This is the first evaluation study to assess the demographic characteristics of the colorectal cancer (CRC) cases detected in the prevalent round of the population-based Colorectal Cancer Screening Programme (CRCSP) in Hong Kong and to explore the effectiveness of the programme on the stage distribution of CRC. METHODS: This study covered the period between 28 September 2016 and 31 December 2018. Information on CRC diagnosis, age and stage at diagnosis were retrieved and reviewed by the Hong Kong Cancer Registry (HKCaR). The CRC detection rate among CRCSP-screened participants and incidence rate among the Hong Kong general population were calculated respectively. The odds ratio (OR) was calculated to measure the strength of association and quantify the effect of CRCSP on stage shift between CRCSP-detected CRC cases and an age-matched cohort of CRC cases diagnosed outside the programme. RESULTS: The CRC detection rate among participants of the CRCSP during the study period was 736.0/100,000, whereas the overall CRC incidence rate among general population of similar age groups was 393.7/100,000. For all ages and both sexes, the OR of stage I CRCSP-detected CRC compared to the CRC from the age-matched cohort was 3.91 (95%CI=3.41-4.48) and the OR dropped to 0.54 (95%CI=0.41-0.70) at stage IV. Meanwhile, the overall OR of CRCSP-detected CRC compared to CRC from the age-matched cohort dropped from 2.24 (95%CI=1.97-2.56) to 1.62 (95%CI=1.40-1.87) with increasing age. CONCLUSION: The present study has demonstrated the initial impact of the CRCSP on shifting the stage at diagnosis towards earlier stage. The benefit of stage-shift was similar for all ages from 60 to 77 in both sexes and seems to increase with younger age. Given the stage-dependent survival outcomes, this stage-shift could lead to a reduction in CRC-associated mortality in Hong Kong in future.

Breast cancer in Hong Kong, Southern China: the first population-based analysis of epidemiological characteristics, stage-specific, cancer-specific, and disease-free survival in breast cancer patients: 1997-2001.

BACKGROUND: Cancer registries have been set up worldwide to provide information for cancer health planning. There are known variations in breast cancer incidence and mortality worldwide. However, breast cancer incidence, pathological characteristics, and survival data is still under-reported in Asian countries. This is the first comprehensive population-based breast cancer study performed using population database of the Hong Kong Cancer Registry. METHODS: A retrospective review of medical records of 8,961 subjects who were diagnosed with breast cancer between January 1, 1997 to December 31, 2001 and followed up to December 31, 2007. Descriptive statistics were employed to analyze the epidemiological and clinical data. Estimates of overall, disease-free, and cancer-specific survival at 5 years were estimated by the Kaplan-Meier method and stage-specific relative survival rates were calculated. RESULTS: A total of 7,630 breast cancer patients' medical records and dataset were available during this period, and 7,449 subjects were eligible for the final analysis. Median follow-up was 84 months. A total of 47.4% were diagnosed with breast cancer at age 49 years and younger; 22.2%, 46.9%, 10.8%, and 4.1% presented at stages I, II, III, and IV, respectively. A total of 53.5% had ER-positive cancer, and 20.3% had HER2-positive cancers; 13.4% had triple-negative cancers. The relative, cancer-specific, and disease-free survival rates at 5 years were 84%, 85.2%, and 81.2%, respectively. DISCUSSION: We performed the first comprehensive population-based breast cancer epidemiology study in Southern China using the Hong Kong Cancer Registry database. This provides a baseline study cohort for comparative studies with other Asian countries and Chinese who have migrated to the West.

A population-based analysis of incidence, mortality, and stage-specific survival of cervical cancer patients in Hong Kong: 1997-2006.

OBJECTIVES: To determine the trends in incidence and mortality of cervical cancer patients diagnosed during 1997 to 2006, and to describe stage-specific survival using population-based cancer registry data. DESIGN: Retrospective, population-based study. SETTING: Hong Kong. PATIENTS: All patients diagnosed with cervical cancer between 1997 and 2006. Patients eligible for survival analysis were followed up till 31 December 2007. MAIN OUTCOME MEASURES: Age-standardised incidence and mortality rates and average annual percent changes in these parameters were calculated using the Poisson regression model. Survival was expressed as relative survival rate using a period approach. Hazard ratios of mortality including 95% confidence intervals for certain variables were estimated using the Cox proportional hazards model. RESULTS: During the 10-year period of the study, overall annual incidence and mortality rates decreased by 4.2% and 6.0%, respectively. Significant rates of reduction were observed in all age-groups except those younger than 45 years. The reduction in incidence of squamous cell carcinoma (3.6% annually) was less than that of adenocarcinoma (5.2%) and other histological types (6.8%). In all, 3807 (86.4%) of the patients were included in survival analysis. The overall 5-year relative survival rate was 71.3% (95% confidence interval, 69.5-73.1%), while the values for stages I, II, III, and IV were 90.9%, 71.0%, 41.7%, and 7.8%, respectively. Age, stage, and histology were independent prognostic factors. Survival of stage IA patients was as good as that of the general population. CONCLUSIONS: As in other industrialised countries, the incidence and mortality rate of cervical cancer were decreasing. Stage-specific population-based cancer survival was available for the first time, and was useful as an indicator of cancer control. Collaboration between public and private sectors to further improve the follow-up data could provide more comprehensive surveillance information.

Risk, pattern and survival impact of second primary tumors in patients with nasopharyngeal carcinoma following definitive intensity-modulated radiotherapy.

AIM: Second primary tumor (SPT) is a serious late complication after definitive radiotherapy for nasopharyngeal carcinoma (NPC). We evaluated the incidence, pattern, risk factors and survival impact of SPT in NPC patients following definitive intensity-modulated radiotherapy (IMRT). METHODS: A retrospective review of 780 consecutive IMRT-treated NPC patients between February 2003 and September 2011 was conducted. Cumulative SPT incidence and overall survival after SPT diagnosis were estimated. Associations between clinical characteristics and SPT risk were analyzed. Standardized incidence ratios (SIR) were calculated using age, gender and calendar-year-specific cancer incidences from the Hong Kong Cancer Registry. RESULTS: At a median follow-up of 7.5 years, 51 SPTs (6.7%) were identified, 22 (43.1%) of which occurred within previous radiotherapy fields. Tongue cancers (31.8%) and sarcomas of the head and neck (31.8%) were the most common in-field SPTs. Age [hazard ratio (HR), 1.051; 95% confidence interval (CI), 1.025-1.078] and smoking status (HR, 1.755; 95% CI, 1.002-3.075) were independent risk factors associated with SPT development. Median overall survival after SPT diagnosis was 2.9 years. There was an 84% increase in cancer risk (SIR, 1.84; 95% CI, 1.37-2.42) compared with the general population. Significant excess risks were observed for sarcoma, tongue, oropharyngeal, prostate and liver cancer. Excess risks were higher beyond 5 years of follow-up. CONCLUSION: Substantial risk of SPT, especially for in-field sarcoma and tongue cancers, exists after definitive IMRT for NPC. SPT severely negates longevity of NPC survivors. High awareness and careful surveillance is warranted for this late lethal complication.

Time trends of lung cancer incidence by histologic types and smoking prevalence in Hong Kong 1983-2000.

The gender difference in epidemiology of lung cancer has been postulated to be due to the higher susceptibility of women to risk factors especially tobacco smoking. Alternatively, such difference may also be explained by some unknown gender-specific etiological factors, which can have been masked if both the female and male prevalence of smoking are high. Hong Kong has a low female smoking prevalence rate and therefore the trend of the female incidence of lung cancer is particularly interesting because it can reflect the effects of the non-smoking related risk factors more clearly. The present study examined the trends of incidence rates for the major histologic types and smoking prevalence from 1983 to 2000 in Hong Kong with respect to gender. The prevalence of daily smokers decreased from 39.7% in 1982 to 22% in 2000 in males and from 5.6 to 3.5% in females. The time trends of the lung cancer incidence (overall or with respect to age and histology) were similar for both genders. The overall incidence decreased progressively throughout the study period, attributable to the decrease in squamous cell, small cell and large cell carcinoma. The decline occurred in all age groups but to a greater extent in the younger age groups. The incidence of adenocarcinoma increased until 1988-1990 and then stabilized. The initial increase was restricted to the older age groups. These temporal patterns suggested that the same etiological factors affected both genders to a different extent but manifested as similar changes in the direction of incidence over time. To confirm this hypothesis, further studies were needed to clarify the nature of these etiological factors for the non-smoking related lung cancer cases.

Understanding sociohistorical imprint on cancer risk by age-period-cohort decomposition in Hong Kong.

BACKGROUND: Research on trends in cancer incidence has usually examined single sites in populations that long ago completed the economic transition. The trends in 11 cancers in three groups in the recently transitioned Hong Kong Chinese population were examined to delineate the effects of economic transition and provide generalised aetiological insights. METHODS: Sex-specific Poisson models were fitted to cancer incidence in Hong Kong (1974-2003) to examine age, period and birth cohort effects. Cancers were grouped as: hormonally modulated (including breast, endometrium, ovary and prostate), infection-related (cervix, liver, nasopharynx, lymphoma and stomach) and lifestyle-related (colorectum and lung). RESULTS: Age-standardised incidence of hormonally modulated female cancers increased for the first generation (women born approximately 1940) to experience puberty in the transitioning environment of Hong Kong. Prostate cancer incidence increased, despite a downturn for the first generation growing up in Hong Kong. Incidence of infection-related cancers decreased, mainly due to birth cohort effects; coinciding with birth for liver cancer and lymphoma, with reaching adulthood for cervical and male nasopharyngeal cancers, and with a generation for stomach cancer. Lifestyle-related cancers had sex-specific declines by birth cohort. CONCLUSION: With economic transition and the associated lifestyle changes, environmentally determined levels of pubertal female hormones may drive intergenerational increases in hormonally related female cancers. Economic development, via improved living conditions, may also reduce infection-related cancers, possibly including prostate cancer; however, the effects depend on transmission dynamics and perhaps specific public health initiatives. In traditional societies, males may benefit from economic development sooner than females.