Incidence and trends of ophthalmic cancer in Singapore: Data from Singapore Cancer Registry

Incidence, Mortality and Five-year Relative Survival Ratio of Prostate Cancer among Chinese Residents in Singapore from 1968 to 2002 by Metastatic Staging

Introduction: This paper examines the incidence, mortality and survival patterns among all Chinese residents with prostate cancer reported to the Singapore Cancer Registry in Singapore from 1968 to 2002 by metastatic staging. Materials and Methods: This is a retrospective population-based study including all prostate cancer cases aged over 20 reported to the Singapore Cancer Registry (SCR) from 1968 to 2002 who are Singapore Chinese residents. Follow-up was ascertained by matching with the National Death Register until 2002. Metastatic status was obtained from the SCR. Age-standardised incidence and mortality rates, as well as the 5-year relative survival ratios (RSRs), were obtained for each 5-year period and grouped by metastatic stage. A weighted linear regression was performed on the log-transformed age-standardised incidence and mortality rates over the study period. Results: In the most recent period of 1998 to 2002, the age-standardised incidence and mortality rates (per 100,000) for prostate cancer among the Chinese were 30.9 (95% CI, 29.1 to 32.8) and 9.6 (95% CI, 8.6 to 10.7), respectively. The percentage increase in the age-standardised incidence and age-standardised mortality rates per year were 5.6% and 6.0%, respectively, for all Chinese Singapore residents. There was an improvement in the 5-year RSRs for Chinese diagnosed with non-metastatic cases from 51.3% in 1973 to 1977, to 76.1% in 1998 to 2002. However, the RSR remains poor (range, 11.1% to 49.7%) for Chinese diagnosed with metastatic prostate cancer. Conclusions: Both age-standardised incidence and mortality rates for prostate cancer among Chinese Singapore residents are still on the rise especially since the 1990s. Since the 1990s, the improvement in RSRs was substantial for the Chinese non-metastatic cases. Key words: Non-metastatic, Population-based, Registry

Radical Radiotherapy in Stage I Non-small Cell Lung Cancer (NSCLC) – Singapore National Cancer Centre Experience

Introduction: The aim of this study was to assess the outcome of radical treatment for stage I non-small cell lung cancer (NSCLC) with external beam radiation therapy. Materials and Methods: A retrospective series of 23 patients with stage I NSCLC treated radically with radiotherapy from September 1997 to December 2004 at the National Cancer Centre, Singapore. Eighteen patients had 3D conformal radiotherapy and 5 patients had 2D planning. The median radiation dose delivered was 55 Gy (range, 50 to 67.5 in 20 to 33 fractions). The estimated median BED10 was 63.9 Gy (range, 57.6 to 70.1). Complete response (CR) rates, overall survival and cause-specific survival rates were analysed for evaluation of treatment results. Local regional failure was defined as disease in the ipsilateral lung and entire mediastinum. Recurrence at the contralateral lung and other distal organs was defined as distant metastases. Survival data were calculated using the Kaplan-Meier method and tested for significance with log-rank statistics. Results: A total of 23 patients (16 males, 7 females) with a median age of 73 years (range, 45 to 88) were analysed. Six (26%) had stage IA and 17 (74%) had stage IB disease. Eleven patients refused surgery and 12 patients were medically inoperable. The median follow-up was 18.9 months (range, 6.2 to 117.4). The overall survival at 2 years and 3 years was 54.7% and 24.3% respectively. The overall cause-specific survival was 57.4% at 2 years and 25.6% at 3 years. Radiological CR was obtained in 6/23 patients (26%) and the median survival was 24.8 months as compared to 20 months in patients who attained partial response (PR) or unknown response (P = 0.24). The median survival for 12 patients who received a BED10 of ≥63.9Gy was not reached as compared to 20 months in 11 patients with BED10 of <63.9 Gy (P = 0.03). Sixteen patients died, 14 due to disease recurrence or progression and 2 of unrelated causes. Seven patients (29.2%) remained alive. The longest surviving patient had a follow-up time of 117.4 months. Four of these 7 patients were disease-free and 3 were alive with disease (2 with bone metastases and 1 with recurrence in the primary site). Conclusion: Our data are consistent with the reported literature for stage I NSCLC treated with radical radiotherapy. Patients who received a higher dose of radiation have a better outcome. The 3-year cause-specific survival of 25.6% is less than ideal and further investigations into dose escalation with modern radiotherapy techniques and perhaps the addition of chemotherapy or new targeted agents to radiation are warranted to improve the outcome. Key words: Dose fractionations, Stereotactic body radiotherapy (SBRT), Survival rates

Squamous Cell Carcinoma and Bowen’s Disease of the Skin in Singapore

Introduction: Non-melanoma skin cancer is one of the commonest cancers in Singapore and worldwide. The aim of our study was to evaluate the demographic and clinicopathological patterns of squamous cell carcinoma (SCC) and Bowen’s disease (BD) of the skin, in order to better understand the characteristics of these tumours in our population. Materials and Methods: Histologically proven cases of SCC and BD seen at our centre between 2002 and 2003 were retrospectively analysed according to age, sex, race, predisposing factors such as immuno-suppression and ultraviolet therapy, site and size of tumour, histological differentiation and subtype, and treatment method. Results: A total of 161 patients were studied – 81 with SCC, 68 with BD, and 12 with both tumours. There were 199 tumours in total – 105 SCC and 94 BD. For both SCC and BD, males outnumbered females (ratio of 2.4:1 and 1.5:1 respectively); patient age averaged 72.9 years and 66.8 years respectively; and Chinese were the majority race. The mean duration to presentation was 21.2 months for SCC compared with 39.9 months for BD, and common symptoms were itch, pain and bleeding for both. The mean tumour size was 19.0 mm and 18.5 mm, and the commonest site was the head and neck for both. Conclusions: SCC and BD show rather similar patient characteristics, with a predominance among males, having a predilection for the head and neck region, and with a tendency towards slow growth. As incidences increase worldwide, it is important for healthcare providers to be adept at recognising and managing non-melanoma skin cancers. Key words: Arsenic, Skin cancer