Racial and ethnic differences in second primary lung cancer risk among lung cancer survivors.

Background: Recent therapeutic advances have improved survival among lung cancer (LC) patients, who are now at high risk of second primary lung cancer (SPLC). Hispanics comprise the largest minority in the United States, who have shown a lower LC incidence and mortality than other races, and yet their SPLC risk is poorly understood. We quantified the SPLC incidence patterns among Hispanics vs other races.

Methods: We used data from the Multiethnic Cohort, a population-based cohort of 5 races (African American, Japanese American, Hispanic, Native Hawaiian, and White), recruited between 1993 and 1996 and followed through 2017. We identified patients diagnosed with initial primary lung cancer (IPLC) and SPLC via linkage to Surveillance, Epidemiology, and End Results registries. We estimated the 10-year cumulative incidence of IPLC (in the entire cohort) and SPLC (among IPLC patients). A standardized incidence ratio (SIR) was calculated as the ratio of SPLC-to-IPLC incidence by race and ethnicity.

Results: Among 202 692 participants, 6788 (3.3%) developed IPLC over 3 871  417 person-years. The 10-year cumulative IPLC incidence was lower among Hispanics (0.80%, 0.72 to 0.88) vs Whites (1.67%, 1.56 to 1.78) or Blacks (2.44%, 2.28 to 2.60). However, the 10-year SPLC incidence following IPLC was higher among Hispanics (3.11%, 1.62 to 4.61) vs Whites (2.80%, 1.94 to 3.66) or Blacks (2.29%, 1.48 to 3.10), resulting in a significantly higher SIR for Hispanics (SIR = 8.27, 5.05 to 12.78) vs Whites (SIR = 5.60, 4.11 to 7.45) or Blacks (SIR = 3.48, 2.42 to 4.84; P < .001).

Conclusion: Hispanics have a higher SPLC incidence following IPLC than other races, which may be potentially due to better survival after IPLC and extended duration for SPLC development. Continuing surveillance is warranted to reduce racial disparities among LC survivors.