With the advancement in diagnostic techniques, including more sophisticated imaging and genetic testing, doctors are now able to detect cancer more accurately and at earlier stages. Coupled with enhanced surveillance programs that monitor patients more closely for signs of cancer, these developments have significantly improved the early detection rates of multiple primary malignancies. Additionally, because cancer treatments have become more effective, patients are living longer, which increases the likelihood of developing another primary cancer over their lifetime. Consequently, the incidence of multiple primary malignancies is on the rise, presenting new challenges and considerations for the ongoing management and care of cancer patients. [1,2]

The International Agency for Research on Cancer (IARC) reported that in 2012, there were 14.1 million new cases of cancer and 8.2 million fatalities due to the disease. These figures are projected to rise to 21.7 million new cancer diagnoses and 13 million deaths by 2030. As a result of this surge, the incidence of patients diagnosed with multiple primary cancers is also anticipated to increase significantly. [3]

Distinguishing between metastases from the original tumor and those from a new primary cancer in patients with a cancer history is challenging but critical. Accurate identification is essential for tailoring treatment approaches, predicting outcomes, and guiding long-term management plans. Recognizing and correctly diagnosing these scenarios are fundamental to ensuring patients receive the most effective therapy based on their cancer's specific characteristics and origins.