Introduction
Appropriately treated differentiated thyroid cancer (DTC) confers an
excellent 10-year survival rate of over 90% for both papillary and
follicular carcinoma1. However up to 30% of patients
experience loco-regional recurrence within 10 years of diagnosis.
The routine use of post-treatment ultrasound (US) surveillance and
thyroglobulin assay allows for early detection of non-palpable recurrent
disease. Treatment options include radioiodine ablation or further
surgical intervention; the former is limited to sub-centimetre lesions
that exhibit radioiodine uptake. Recurrent disease may be iodine
negative i.e. dedifferentiated in up to 30% of patients and may persist
despite ablative treatment 3. For these cases,
surgical excision remains the mainstay of treatment.
The localisation of recurrent disease and identification of important
structures to be preserved in previously dissected necks is challenging
due to the presence of fibrotic scar tissue, neovascularisation and
modified anatomy. The complication rates for transient and persistent
hypoparathyroidism and recurrent laryngeal nerve injury are reportedly
significantly higher in secondary vs primary surgery3.
Various techniques are employed for pre-operative localisation of
non-palpable lesions in patients with cytologically proven recurrent DTC
(rDTC) in the neck. These include intra-operative US guidance,
I131 guided gamma probe and Methylene blue dye.
The use of charcoal tattooing for identification of recurrence of
malignancy is well established in secondary breast surgery where it has
been shown to be both safe and effective4 and in
recent years, has been shown to be successful in the surgical management
of rDTC5,6.
We aim to inform the readership of the technical aspects of using
activated charcoal suspension injection for the localisation of DTC in
the neck of previously treated patients based on our experience
at [removed for blind peer review].