The Analysis of Incidence, Risk and Survivorship of Second Primary Malignancies in Patients with Six Most Common Cancers in Taiwan---A National Population-Based Study

The advance in cancer therapy has led to prolong survival probability in Taiwan, and also increases the risk of second primary malignancies (SPMs). In addition, the overall cancer incidence is increasing year by year. As a result, the occurrence of SPMs after primary cancer has become an issue of concern to clinicians and patients. However, very few reports are available on the incidence and risk of second primary cancers, particularly for Asian prevalent cancers, and most of these are single-institute reviews with relatively small case numbers and short follow-up. Our previous study using the cancer database from the Taiwan Cancer Registry (TCR) showed a 24% increased risk of second cancers in the patients with nasopharyngeal carcinoma (NPC) compared to the general population in Taiwan (SIR=1.24, 95% CI=1.15-1.33), and a 43% increased risk in young breast cancer patients (SIR=1.43, 95% CI =1.29-1.58). The findings of the patients at high risk for SPMs and the second cancer types in association with a primary cancer may help clinical management for patients presenting with double cancers and the strategies for prevention. This is important because the patients diagnosed with multiple, independently derived, primary cancers versus those diagnosed with a single primary cancer with metastatic lesions may have different prognosis and response to therapy and, therefore, will have different treatment options. This year, we have published 2 papers regarding our previous research on second cancers following NPC and young-age breast cancer, respectively, which are unique in Taiwan. Following the study, we will continue to investigate six of the most common cancers in Taiwan, including oral/pharyngeal, colon and rectum, esophageal, gastric, bladder and invasive cervical carcinomas. We aim to address the following issues for each of these primary cancers using the population-based data provided by Bureau of Health Promotion, Department of Health, Executive Yuan: (i) to determine the standardized incidence ratios for all types of second caners and compare the risks and SPM types between Taiwan and Western countries; (ii) to calculate cumulative incidences of SPMs; (iii) to examine the association between the risk of SPMs and the length of follow-up time; (iv) to evaluate the association between the risk of SPMs and onset age of the first primary cancer; (v) to estimate the impact of SPMs on survival probability. In summary, we aim to establish a complete analysis of second cancers for six of the most common cancers in Taiwan. This research is important to establish our local data and furthermore, to fill the deficiency of large-scale population-based studies of second primary cancers among Asian population.

Project ID:PC9808-0582
External Project ID:NSC98-2314-B182-029-MY2