JMIR Publications

ABSTRACT

Background:

Little is known about the real-world maps of primary malignancies and their following primary malignancies, as well as the associated survival status for the patterns of multiple primary carcinoma (MPC).

Objective:

We aimed to establish the patterns and combinations of MPC across a wide range of cancers and to assess whether the mortality status of patients with MPCs varies according to their characteristics and disease status.

Methods:

We retrospectively screened the data of 1,560 patients with MPC from the 86 public health institutions in Shanghai during 2002-2015. The distribution of the frequency and proportion of primary carcinoma (PC) combinations were depicted, and a life table was used to calculate the 1- to 5-year survival rates. Cox regression analysis was performed to analyze the survival risk factors of the first and second PCs.

Results:

The map showed that the most frequent first PCs were colorectal (13.08%), breast (11.60%), and stomach (9.29%), while the most frequent second PCs were lung (17.56%), colorectal (16.28%), and stomach cancers (9.10%). The most common combinations included colorectal + lung, colorectal + stomach, colorectal + prostate. The first PCs of skin and lung cancer had the lowest survival rate, and the second PCs of pancreas and liver cancer had the lowest survival rates. When the latency between diagnoses of PCs was ≤ 12 months, patients had a higher risk of cancer-specific mortality. Higher risk groups included those > 65 years old with III + IV cancers.

Conclusions:

These findings highlight specific PC combinations with low survival rates, as well as their risk factors. Comprehensive prevention and control strategies for MPC should be developed, and clinicians should be aware of the risks of MPC in vulnerable populations at an early diagnosis stage.