Multiple primary malignant neoplasms

Background: The high effectiveness of cancer screening and therapies resulted in the increased diagnosis of multiple primary malignancies (MPMNs) in Taiwan. The aim of the present study was to investigate the clinical data of patients and to determine the frequency and clinical features of MPMNs. Methods: Between January 2010 and December 2014, a total of 2518 patients were screened and obtained retrospectively from the Tumor Registry Center of a metropolitan hospital. We quantified the clinical features and the most common cancer pairs of MPMNs using statistical and epidemiological indicators. Results: Two hundred and eleven patients with MPMNs were evaluated. The median age at initial cancer diagnosis was 63 years old (range 12-100 years). The median age of diagnosis of secondary cancer was 67 years old (range 35-95 years). The median time between initial and secondary cancer diagnoses was 5 months (range 0-57.1). The overall incidence of MPMNs was 8.38%, and the male: female ratio was 2.01:1. The most frequent types of cancer at secondary diagnosis were digestive (79 patients, 3.05%), breast (22 patients, 0.87%), liver (22 patients, 0.87%), head-neck (18 patients, 0.71%), and bladder cancer (14 patients, 0.56%). In women, the most frequent types of cancer at secondary diagnosis were digestive (25 cases, 2.21%), breast (22 cases, 1.95%), liver (11 cases, 0.97%), lung (8 cases, 0.71%), and gynecologic cancer (7 cases, 0.62%). In men, the most frequent types of cancer at secondary diagnosis were digestive (54 cases, 3.89%), head-neck (16 cases, 1.15%), liver (11 cases, 0.79%), bladder (10 cases, 0.72%), and prostate cancer (10 cases, 0.72%). The most common cancer pairs in males were digestive/digestive (22 cases, 1.59%), head-neck/head-neck (4 cases, 0.29%), lung/digestive (3 cases, 0.22%), and prostate/bladder (3 cases, 0.22%). In addition, tobacco smoking, alcohol consumption, and betel-chewing were observed to be important risk factors for the development of MPMNs. Conclusion: Indeed, the cancer registries can help us understand the disease better and use our resources to the best effect in prevention and treatment of MPMNs. In the present study, we discovered that patients with MPMNs tend to be older than those with a single primary malignant neoplasm. In conclusion, the clinical features and the most common cancer pairs of MPMNs are demonstrated in the present study. Based on these data, further analysis of the relationship between them is worthwhile.