Purpose: We examined overall survival outcomes of a national cohort to determine suitable treatments and prognostic factors in patients with metachronous second primary head and neck squamous cell carcinomas (mspHNSCCs) at different stages and sites.
Patients and Methods: We analyzed data of mspHNSCCs collected from Taiwan Cancer Registry databases. The patients were categorized into four groups based on the treatment modality: Group 1 (control arm, chemotherapy [CT] alone), Group 2 (reirradiation [re-RT] alone with intensity modulation radiotherapy [IMRT]), Group 3 (concurrent chemoradiotherapy [CCRT] alone [irradiation with IMRT]), and Group 4 (salvage surgery with or without RT or CT).
Results: We enrolled 1741 mspHNSCCs patients without distant metastasis. Multivariate Cox regression analyses revealed that Charlson comorbidity index (CCI) ≥6, stage of second HNSCC, stage of first HNSCC, and duration from first primary HNSCC of >3 years were significant poor independent prognostic risk factors for overall survival. After adjustment, adjusted hazard ratios (aHRs; 95% confidence intervals [CIs]) for overall all cause mortality risk at mspHNSCCs clinical stages III and IV were 0.72 (0.40-1.82), 0.52 (0.35-0.75), and 0.32 (0.22-0.45) in Groups 2, 3, and 4, respectively. A Cox regression analysis indicated that a re-RT dose of ≥6000 cGy was an independent protective prognostic factor for treatment modalities.
Conclusions: Charlson comorbidity index (CCI) ≥6, stage of second HNSCC, stage of first HNSCC, and duration from first primary HNSCC of >3 years were significant poor independent prognostic risk factors for overall survival. A re-RT dose of ≥6000 cGy may be necessary for mspHNSCCs.