F-18 FDG PET/CT Imaging of Anal Canal Squamous Cell Carcinoma

The role of ¹⁸fluoro-deoxy glucose combined position emission and computed tomography in the clinical management of anal squamous cell carcinoma

AIM

Anal squamous cell carcinoma (SCC) is uncommon in the western world but continues to increase in incidence. Optimal treatment and outcome are dependent upon pretreatment staging strategies. We evaluate the role of ¹⁸fluoro-deoxyglucose (¹⁸FDG) combined position emission and computed tomography (PETCT) in the management of anal SCC.

METHOD

Patients with a histologically confirmed anal SCC underwent standard staging investigations, including computed tomography, Magnetic resonance imaging and examination under anaesthetic. A tumour, node, metastasis (TNM) system was used. All patients subsequently underwent additional whole-body ¹⁸FDG PETCT scanning. Management was planned accordingly, blinded to ¹⁸FDG PETCT findings, at a multidisciplinary meeting, and reviewed again following disclosure of PETCT results.

RESULTS

Forty patients (24 men), with a median age of 57 years (range 38-87 years), were prospectively recruited. All primary tumours were ¹⁸FDG avid. PETCT did not alter the T stage but did result in disease upstaging (N and M stages). Management was altered in five (12.5%) patients: one patient was identified to have an isolated distant metastasis, and four patients had ¹⁸FDG-avid lymph nodes not otherwise detected, all of which were tumour-positive on fine needle aspiration cytology/biopsy.

CONCLUSION

PETCT upstages anal SCC and influences subsequent management. PETCT should be considered in the staging of anal SCC, although the definitive benefit of such a strategy requires further evaluation.