Clinical features and survival of patients with multiple primary malignancies

Background: Multiple primary malignancies (MPM) are characterized by two or more primary malignancies in the same patient, excluding relapse or metastasis of prior cancer. We aimed to elucidate the clinical features and survival of MPM patients.

Aim: To elucidate the clinical features and survival of MPM patients.

Methods: A retrospective study of MPM patients was conducted in our hospital between June 2016 and June 2019. Overall survival (OS) was calculated using the Kaplan-Meier method. The log-rank test was used to compare the survival of different groups.

Results: A total of 243 MPM patients were enrolled, including 222 patients with two malignancies and 21 patients with three malignancies. Of patients with two malignancies, 51 (23.0%) had synchronous MPM, and 171 (77.7%) had metachronous MPM. The most common first cancers were breast cancer (33, 14.9%) and colorectal cancer (31, 14.0%). The most common second cancers were non-small cell lung cancer (NSCLC) (66, 29.7%) and gastric cancer (24, 10.8%). There was no survival difference between synchronous and metachronous MPM patients (36.4 vs 35.3 mo, P = 0.809). Patients aged > 65 years at diagnosis of the second cancer had a shorter survival than patients ≤ 65 years (28.4 vs 36.4 mo, P = 0.038). Patients with distant metastasis had worse survival than patients without metastasis (20.4 vs 86.9 mo, P = 0.000). Following multivariate analyses, age > 65 years and distant metastasis were independent adverse prognostic factors for OS.

Conclusion: During follow-up of a first cancer, the occurrence of a second or more cancers should receive greater attention, especially for common concomitant MPM, to ensure early detection and treatment of the subsequent cancer.