Treatment strategies and outcomes in patients with synchronous multiple primary malignancies involving lung cancer.

BACKGROUND

Synchronous multiple primary malignancies (sMPMs) involving lung cancer present complex clinical challenges requiring individualized treatment strategies. While surgical outcomes have been reported, data on long-term outcomes, including the development of new additional primary malignancies after surgery, remain limited.

METHODS

We retrospectively analyzed 85 patients with sMPMs involving lung cancer selected from 2820 patients who underwent pulmonary resection between 2008 and 2020. Surgical strategies, treatment sequence, perioperative outcomes, and long-term survival were evaluated. The incidence of new additional primary malignancies was assessed using person-time and competing risk analysis.

RESULTS

Among the 85 patients, lung cancer was treated first in 30, the other malignancy first in 41, and simultaneous surgery was performed in 14. Lobectomy was the most common procedure (73%). Postoperative complications occurred in 22% of patients. The 5-year recurrence-free survival and overall survival rates were 63 and 69%, respectively. During 485.3 person-years of follow-up, 11 patients developed new additional primary malignancies, corresponding to an incidence rate of 22.7 per 1000 person-years. In competing risk analysis, the cumulative incidence was 6.0% at 5 years and 20.3% at 10 years after lung cancer surgery.

CONCLUSION

Surgical treatment for lung cancer is feasible in selected patients with sMPMs. The occurrence of new additional primary malignancies should be recognized as a clinically relevant aspect of postoperative management.