Squamous cell carcinoma of the tonsillar remnant--clinical presentation and oncological outcome

History of tonsillectomy and risk of oropharyngeal cancer

OBJECTIVE

To investigate whether palatine tonsillectomy in youth influences the risk of oropharyngeal cancers (OPC) by assessing the association between history of tonsillectomy and risk of tonsillar, base of tongue (BOT) cancer, and other head and neck cancers (HNC).

MATERIALS AND METHODS

RACKAM was a case-case study comparing frequency of tonsillectomy history in individuals diagnosed with HNC from 2013 to 2018 in 15 centers across France. History of tonsillectomy was defined using combined assessment of patients' recollections and surgeons' visualizations of tonsil area. OPC subsite-specific odds ratios (OR) of tonsillectomy were calculated using multinomial logistic regression with non-oropharyngeal HNC as reference.

RESULTS

1045 patients were included in the study. Frequency of tonsillectomy was 19.5% in patients with tonsillar cancer (N = 85), 49.3% in BOT (N = 76), 33.8% in other oropharyngeal cancers (N = 202) and 38.0% in non-oropharyngeal HNC (N = 682). History of tonsillectomy was inversely associated with tonsillar cancer (adjusted OR 0.4; 95% CI 0.2-0.8), and positively associated with BOT cancer (adjusted OR 1.8; 95% CI 1.1-3.1), but was not associated with all OPC combined (adjusted OR 1.1; 95% CI 0.8-1.4). Sensitivity analyses considering only patients' or surgeons' assessments of tonsillectomy provided comparable results.

CONCLUSION

We confirm the long-term protective effect of tonsillectomy performed in youth on future risk of tonsillar cancer, and our study is the second to report a concurrent increased risk of BOT cancer. Our data suggest that tonsillectomy in youth shifts the site of the first diagnosed oropharyngeal tumor and has a limited impact on overall risk of OPC.

Palatine tonsil SUVmax on FDG PET-CT as a discriminator between benign and malignant tonsils in patients with and without head and neck squamous cell carcinoma of unknown primary

AIM

To analyse the maximum standardised uptake value (SUVmax) ratio between tonsils in patients with and without tonsillar carcinoma to determine useful diagnostic thresholds.

MATERIALS AND METHODS

Positron-emission tomography (PET)/computed tomography (CT) examinations of patients with suspected head and neck squamous cell carcinoma (SCC) and controls from April 2013 to September 2016 were reviewed retrospectively. Tonsillar SUVmax ratios (ipsilateral/contralateral for malignant tonsils, maximum/minimum for patients without [controls]) were calculated and used to construct a receiver operating characteristic (ROC) curve.

RESULTS

Twenty-five patients had tonsillar carcinoma (mean SUVmax ratio of 2, range 0.89-5.4) and 86 patients acted as controls (mean SUVmax ratio of 1.1, range 1-1.5). Using the ROC, the most accurate SUVmax ratio for identifying malignancy was >1.2 (77% sensitivity, 86% specificity). A potentially more clinically useful SUVmax ratio is ≥1.6 with 62% sensitivity and 100% specificity.

CONCLUSION

An SUVmax ratio between tonsils of ≥1.6 is highly suspicious for SCC and could be used to direct site of biopsy. Some malignant tonsils had normal FDG uptake; therefore, PET/CT should not be used to exclude tonsillar cancer. Minor asymmetrical uptake is frequently seen in non-malignant tonsils and does not necessarily require further investigation. Due to the single centre nature of this study and the recognised variation in SUV measurements between PET scans, other centres may need to develop their own cut-offs.