Non-thyroidal second primary malignancy in papillary thyroid cancer patients

Area of Science:

• Oncology
• Epidemiology
• Medical Statistics

Background:

• Non-thyroidal second primary malignancy (NTSPM) occurrence in papillary thyroid cancer (PTC) patients is documented, yet epidemiological data remain conflicting.
• Understanding NTSPM incidence and risk factors is crucial for comprehensive patient care and surveillance strategies.

Purpose of the Study:

• To determine the incidence of NTSPM in a large cohort of PTC patients.
• To identify potential risk factors associated with the development of NTSPM.

Main Methods:

• Retrospective analysis of a single-center cohort of 773 consecutive PTC patients diagnosed between 1988 and 2018.
• Minimum follow-up of 2 years; NTSPM defined as any histologically confirmed primary malignancy outside the thyroid.
• NTSPM categorized as anachronous, synchronous, or metachronous based on diagnosis timing relative to PTC.

Main Results:

• The incidence of NTSPM was 15.5%, with a Standardized Incidence Ratio (SIR) of 2.70 compared to the general population.
• First-degree family history of malignancy (HR: 2.06) and younger age at PTC diagnosis (HR: 1.04) were significant risk factors for metachronous NTSPM.
• Median follow-up was 9.9 years; 83.3% of patients were female, with a median age of 47.0 years at PTC diagnosis.

Conclusions:

• NTSPM is a notable concern in PTC patients, occurring more frequently than in the general population.
• A first-degree family history of malignancy is a strong predictor for developing multiple primary malignancies.
• Early detection and risk factor assessment are vital for managing patients with PTC and potential secondary malignancies.