Distinct patterns of occurrence, common associations, and survival of patients with second primary maligancies

Abstract

Background: Multiple primary malignancy (MPM) is defined as occurrence of two or more synchronous or metachronous primary malignancies. With the rise in cancer burden and meticulous screening of index primary malignancy (IPM) during treatment, increased incidence of second primary malignancy (SPM) is expected. This study was undertaken with an attempt to analyze the incidence, commonest associations, management strategies, and clinical outcomes of MPM. Materials and Methods: This is an observational retrospective study carried out in a single institute with patients registered between 1st January 2015 and 31st August 2019. The International Association of Cancer Registries and International Agency for Research on Cancer (IACR/IARC) definition was used for identification of IPM and SPM. Synchronous SPM was defined as malignancy occurring within 6 months from the diagnosis of IPM. Results: Out of 16,461 registered patients during the study interval, 44 (0.26%) cases were found to have MPM. A total of 31 (70.5%) cases were women and 13 (29.5%) cases were men. Median age at presentation of IPM was 48 years and of SPM was 56 years, with median duration between two primaries being 38 months. Seven patients (15.9%) had synchronous malignancies. Gynecological tumors were the most common site of IPM presentation (n = 14, 31.8%) followed by breast (n = 09, 20.5%) and head and neck tumors (n = 07, 15.9%), respectively. The most common SPM was gynecological tumors (n = 12, 27.3%) followed by gastrointestinal malignancies (n = 10, 23.3%). Curative treatment was offered to 88% of patients with IPM and 70% patients with SPM. At a median follow-up of 365 days, 21 (47.72%) patients were disease free, six (13.6%) died of disease and nine (20.5%) were lost to follow-up. Conclusion: The study emphasizes the importance of detecting SPM as a result of improved diagnostic and screening procedures. Clinicians should be aware of it and offer multidisciplinary management.