DNA ploidy, S-phase fraction and associations with 2-18F-fluoro-deoxy-2-D-glucose positron emission tomography findings before and during therapy of head and neck squamous cell carcinoma.

Objectives: The main purpose of this study was to investigate the feasibility of fine needle aspiration (FNA) of neck node metastases in head and neck squamous cell carcinoma (HNSCC) for evaluating changes in DNA ploidy and S-phase fraction (SPF) during cytotoxic treatment. The results of flow cytometric (FCM) and image cytometric (ICM) analyses of ploidy were compared. Secondly, the association of SPF and ploidy with the metabolic rate (MR) of 2-18F-fluoro-deoxy-2-D-glucose (FDG) in positron emission tomography (PET) was studied.

Material And Methods: Between 1993 and 1999, 47 patients with locally advanced, non-resectable HNSCC underwent FDG PET prior to (PET1) and early during (PET2) cytotoxic radical treatment. The MR of FDG was calculated separately in primary tumours and lymph node metastases. Immediately after both PET scans, FNA of node metastases was done in 29 patients at PET1 and in 27 at PET2. DNA ploidy was evaluated using FCM and manually using ICM. The SPF was evaluated using FCM only.

Results: At PET1 it was possible to evaluate the SPF using FCM in only 13/29 aspirations due to a poor cell yield or large amounts of debris. Ploidy was obtained in 23/29 aspirates using FCM and in 27/29 using ICM. A discordance in ploidy findings was apparent, with more non-diploid clones being detected by ICM than FCM. Eradication of non-diploid clones during therapy was observed in six cases using FCM, of which only one was confirmed by ICM. Neither SPF nor ploidy status showed any strong correlation with the MR of FDG.

Conclusion: FNA of HNSCC metastases demands a high and qualitatively good cell yield for FCM examinations. ICM is laborious but feasible and offers more accurate detection of non-diploid cell clones. Ploidy and SPF were not strongly associated with FDG metabolism.