Beyond diabetes mellitus: role of metformin in non-muscle-invasive bladder cancer

INTRODUCTION@#Usage of metformin is associated with improved survival in lung, breast and prostate cancer, and metformin has been shown to inhibit cancer cell growth and proliferation in in vitro studies. Given the lack of clinical data on metformin use in patients with bladder cancer, we aimed to evaluate the role of metformin in their oncological outcomes.@*METHODS@#Medication use data from a prospectively maintained database of 122 patients with non-muscle-invasive bladder cancer treated with intravesical Bacille Calmette-Guerin (BCG), who were recruited under a randomised, double-blinded, controlled clinical trial, was collected and analysed. Kaplan-Meier curves were used to assess overall survival (OS) and disease-specific survival (DSS).@*RESULTS@#At a median follow-up duration of 102 (range 3-357) months, 53 (43.4%) patients experienced disease recurrence and 21 (17.2%) experienced disease progression. There was no significant difference in mortality between patients with and without diabetes mellitus. There was significant difference in OS between patients without diabetes mellitus, patients with diabetes mellitus on metformin and patients with diabetes mellitus but not on metformin (p = 0.033); patients with diabetes mellitus on metformin had the best prognosis. Metformin use was associated with significantly lower DSS (p = 0.042). Other oral hypoglycaemic agents, insulin or statins were not associated with disease recurrence or progression.@*CONCLUSION@#Metformin use was associated with improved oncological outcomes in patients with non-muscle-invasive bladder cancer treated with intravesical BCG. Prospective studies with larger patient populations are needed to validate the role of metformin as potential therapy for bladder cancer.

The 5th Conference on Asian Trends in Prostate Cancer Hormone Therapy.

The Conference on Asian Trends in Prostate Cancer Hormone Therapy is an annual forum for Asian urologists now in its 5th year. The 2006 conference, held in Bali, Indonesia, was attended by 27 leading urologic oncologists from China, Indonesia, Japan, Korea, Singapore, and Taiwan and featured a packed program of presentations and discussions on a wide range of topics such as relationships among clinicians and the newly opened Asia Regional Office for Cancer Control of the International Union Against Cancer (UICC), detection rates of prostate cancer by biopsy in each of the 6 Asian countries, and favored treatment modalities for hormone-refractory prostate cancer (HRPC) in each country. The first session of the conference kicked off with a keynote lecture entitled "Activities of the UICC ARO". UICC's new office will be the nerve center for its activities in the Asia region. Along with the Asian Pacific Organization for Cancer Prevention (APOCP), UICC aims to shift the focus of attention to cancer control. As such APOCP's long-running publication the APJCP is to be re-launched as the Asian Pacific Journal of Cancer Control. Although UICC is primarily concerned with cancer, several risk factors for cancer are common also to other non-communicable diseases such as diabetes and heart disease, and an important strategy is to implement measures to control these various pathologic conditions as a whole. Apart from contributing to an Asian prostate cancer registry the UICC-ARO will provide training courses, working groups, and assistance in collecting and processing data. The keynote lecture was followed by a roundtable discussion on possible ways in which clinicians from each Asian country can work with UICC. A number of suggestions were put forth including better registration, epidemiology research, possible implementation of UICC prostate cancer guidelines, early detection and screening, and roles of diet and phytotherapy. The underlying reasons for the large but dwindling difference in incidence rates of prostate cancer in various regions of Asia should be studied while the opportunity lasts. Session 2 was devoted to 6 presentations on detection rates by biopsy in each country. Although biopsy is the gold standard for detecting prostate cancer in most areas, indications for conducting biopsy are different in each country. For example, in Indonesia doctors may use PSAD 0.15 as the cutoff level. TRUS-guided biopsy is most widely used in Asian countries. Traditional sextant biopsy is often performed, although multiple-core biopsy is commonly available and associated with better detection rates, especially in men with large prostate volume. Positive DRE, high PSA, and older age were identified as factors associated with high biopsy detection rate, although elevated PSA has limited specificity. First biopsy in men with elevated PSA had a positive detection rate of approximately 30% in all countries. Community-based screening in some countries has an overall detection rate of approximately 1%.The favorable treatment modality for HRPC was the subject of the final session. First priority for doctors in all 6 countries is to maintain serum testosterone at castration level. Many therapeutic options are available, from cytotoxic drugs to traditional herbal medicines Chemotherapeutic agents such as estramustine, docetaxel, cyclophosphamide, and mitoxantrone are often given to patients with HRPC although not all are available in every country. Prednisone and dexamethasone are used for secondary hormonal therapy. External beam radiotherapy, radioisotopic drugs such as strontium 89, and bisphosphonates are common choices to control bone pain.