Malaysia, Brunei, Singapore, Indonesia, East Timor and the Philippines constitute peninsular and island South-East Asia. For reasons of largely shared ethnicity, with Chinese elements added to the basic Austromalaysian populations, as well as geographical contiguity, they can be usefully grouped together for studies of chronic disease prevalence and underlying risk factors. The fact of problems are shared in common, particularly regarding increasing cancer rates, underlines the necessity for a coordinated approach to research and development of control measures. To provide a knowledge base, the present review of available data for cancer registration, epidemiology and control was conducted. The most prevalent cancer site in males is the lung, followed by the liver, colon or the prostate in the majority of cases, while breast and cervical cancers predominate in most female populations. However, there are interesting differences among the racial groups, particularly regarding the stomach. General tendencies for increase in adenocarcinomas but decrease in squamous cell carcinomas and gastric cancer, point to change in environmental influence over time. Variation in risk factors depends to some extent on the level of economic development but overall the countries of the region face similar challenges in achieving effective cancer control. A major task is persuading the general populace of the efficacy of early detection and clinical treatment.
PURPOSE: In premenopausal women with metastatic hormone receptor-positive breast cancer, hormonal therapy is the first-line therapy. Gonadotropin-releasing hormone analogue + tamoxifen therapies have been found to be more effective. The pattern of recurrence risk over time after primary surgery suggests that peri-operative factors impact recurrence. Secondary analyses of an adjuvant trial suggested that the luteal phase timing of surgical oophorectomy in the menstrual cycle simultaneous with primary breast surgery favourably influenced long-term outcomes.
METHODS: Two hundred forty-nine premenopausal women with incurable or metastatic hormone receptor-positive breast cancer entered a trial in which they were randomised to historical mid-luteal or mid-follicular phase surgical oophorectomy followed by oral tamoxifen treatment. Kaplan-Meier methods, the log-rank test, and multivariable Cox regression models were used to assess overall and progression-free survival (PFS) in the two randomised groups and by hormone-confirmed menstrual cycle phase.
RESULTS: Overall survival (OS) and PFS were not demonstrated to be different in the two randomised groups. In a secondary analysis, OS appeared worse in luteal phase surgery patients with progesterone levels <2 ng/ml (anovulatory patients; adjusted hazard ratio 1.46, 95% confidence interval [CI]: 0.89-2.41, p = 0.14) compared with those in luteal phase with progesterone level of 2 ng/ml or higher. Median OS was 2 years (95% CI: 1.7-2.3) and OS at 4 years was 26%.
CONCLUSIONS: The history-based timing of surgical oophorectomy in the menstrual cycle did not influence outcomes in this trial of metastatic patients. ClinicalTrials.gov number NCT00293540.
Study site: Bangladesh, The Philippines, China, Nigeria,
Indonesia, Malaysia, Taiwan, Morocco, and Vietnam