Synchronous and metachronous malignancies: Analysis of the Minneapolis Veterans Affairs (VA) tumor registry

Purpose: Multiple primary malignancies (MPMs) are increasing as cancer survivorship improves. A large analysis of the SEER database estimates that approximately 16 % of new cancers reported to their registry represent a second or higher order malignancy. The purpose of this study is to estimate the number of MPM diagnoses and to define differences in synchronous and metachronous cancers in the Veterans Affairs (VA) population. Methods: The primary objective of this study was to determine the proportion of second or higher order cancers diagnosed at the Minneapolis VA Medical Center from 1 January 2005 to 31 December 2009. The secondary objectives were to analyze and compare correlative demographic, exposure, clinical, and tumor data among those with synchronous and metachronous malignancies. We included any patient with a diagnosis of a malignant cancer during the study period. Result: A total of 4,449 patients were diagnosed with malignancies during the study period. Of these, 506 patients (11.4 % of cancer diagnoses) had a diagnosis of a second or higher order malignancy. Of the 506 patients, 124 (24.3 %) had synchronous malignancies and 383 (75.5 %) had metachronous malignancies. The most common malignancy pairing was prostate cancer with bladder/ureter cancer (12 %) of MPM diagnoses. Differences between patients with synchronous and metachronous second occurrences were identified. Conclusion: Multiple primary malignancies are a growing area of interest in cancer survivorship. At our institution, approximately 1 in 9 new cancer diagnoses during the 5-year study period represented second-order malignancies. Our data suggest that the VA population is at risk of developing second primary cancers. Further analysis of this population to identify unique risk factors is warranted.