Genetic alterations between primary head and neck squamous cell carcinoma and recurrence after radiotherapy: recurrence, genetically related cancer, or second primary?
BACKGROUND
In the attempt to characterize the genetic bases of recurrent head and neck squamous cell carcinoma (HNSCC) after radiotherapy (RT), the authors compared the molecular profiles of primary tumors and recurrences.


METHODS
TP53 gene status and instability at 10 microsatellite markers were determined in pre-RT lesions and corresponding local recurrences in a series of 16 HNSCCs.


RESULTS
Eight (50%) HNSCCs showed both TP53 and microsatellite instability (MSI) status concordance in pre- and postirradiation biopsies; 3 (18.7%) showed discordance of both TP53 and MSI status; and finally 5 (31.2%) had discordance at only 1 genetic test. Accordingly, the authors interpreted as true recurrence the 8 concordant cases, and as true second primary malignancies the 3 discordant ones. In the remaining 5 cases with partial DNA correspondence, the exact nature of the new lesion only partially related to the original cancer is a matter of discussion. Patients showing the same mutations among pre- and post-RT HNSCCs had a longer disease-free interval (DFI) and better survival than those showing discordant genetic features (log-rank test, P = .0045).


CONCLUSIONS
Post-RT recurrent HNSCCs are genetically heterogeneous. The genetic characterization of the recurrence, especially in those cases with a particularly short DFI showing partially discordant mutations, might have a useful clinical relevance in the restaging process.
Deganello
Alberto
A
Department of Otolaryngology/Head and Neck Surgery, University of Florence, Florence, Italy. adeganello@hotmail.com
Franchi
Alessandro
A
Sardi
Iacopo
I
Pignataro
Lorenzo
L
Leemans
C René
CR
Gallo
Oreste
O
D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000532:radiotherapy*; D016158:Genes, p53; D006258:Head and Neck Neoplasms / Q000235:genetics* / Q000532:radiotherapy*; D006801:Humans; D019656:Loss of Heterozygosity; D053842:Microsatellite Instability; D009154:Mutation; D009364:Neoplasm Recurrence, Local / Q000235:genetics*; D016609:Neoplasms, Second Primary / Q000235:genetics; D016896:Treatment Outcome