Andrea Howes - IMAGING IN MELANOMA

IMAGING IN MELANOMA –LOCAL GUIDELINES

Dr Andrea J HowesConsultant Radiologist

St Helens and Knowsley NHS Trust

Local Imaging Guidelines – how to image?

• Options include CXR, ultrasound, CT, MR, and PET CT, as well as sentinel node mapping and biopsy

• There are advantages and disadvantages for each

Local Imaging Guidelines – how to image?

• Imaging should be performed after histological examination of primary and clinical assessment

• This avoids unnecessary imaging of stage 1 patients

• Within any clinical stage, specific symptoms or signs suggestive of metastases should be imaged accordingly

Stage 1

• There is no evidence for any benefit of imaging in stage 1 disease

Stage 2

• SLNB is performed locally for further staging

• This is expensive and time consuming so CXR and US should be performed prior to this (although no evidence for imaging in stage 2A)

• CT results in large numbers of false positives with resulting anxiety, re-scan and high radiation burden

Stage 3

• Positive SLNB or clinical adenopathy• CT of chest / abdomen for nodes in neck or

axilla and abdomen / pelvis for groin nodes• Yield low if nodes not palpable (0.5 – 3.7%)• Yield higher if palpable nodes (4 – 16%)• MR of neck nodes may be helpful• False positives are still a significant problem

Stage 4

• CT of chest, abdomen and pelvis• Further investigations as clinically

indicated• No evidence for imaging the brain unless

symptomatic

PET CT

• Indications for PET CT are very specific nationally

• Locally, the only melanoma indication is where metastectomy is being considered eg: in a patient with a pulmonary nodule, to establish whether it is a metastasis and to look for evidence of other disease not seen at CT

REFERENCE

“Role of Imaging Investigations in the Staging of Primary Cutaneous Melanoma – Recommended Guidelines for MCCN with Summary of Available Evidence.”

Dr J C Herbert October 2009

SENTINEL LYMPH NODE BIOPSY IN MELANOMA – THE

WHISTON EXPERIENCE

Dr Andrea J HowesConsultant Radiologist

St Helens and Knowsley NHS Trust

CONSULTANT RADIOLOGIST EXPERIENCE

• Whiston was one of the first centres in the country to perform SLNB

• Dr J Herbert started SLN imaging in November 1999

• Dr A Howes started SLN imaging in 2004• From commencing in November 1999 to end of

April 2010 we had performed 564 procedures

NUCLEAR MEDICINE DEPARTMENT REQUIREMENTS

• Large amount of legislation!• The Radiologist has to have a licence issued by the

Health Minister (ARSAC licence) to use radioactive isotopes – there are specific training requirements

• The licence is site specific• Another doctor may work under a colleagues certificate

if it is only a short-term temporary absence, provided you are working under the certificate holder's written directions. 

• The licence holder is responsible for the operating surgeons involvement with the isotope

NUCLEAR MEDICINE DEPARTMENT REQUIREMENTS

• The department also has to be appropriately licensed (including the HSE) and needs access to a radiopharmacy (with appropriate transport licensing if required)

• Single or dual headed gamma camera• SPECT CT capability may be of benefit• Appropriately trained radiographers / nuclear

medicine technicians

WHAT DOES IT INVOLVE?

• Time consuming!• Technitium 99m (Tc99m) labelled colloid• Injected intradermally around primary

excision site• Dynamic images obtained allow

visualisation of channels and can be useful to resolve problems such as kinks in channels (20 minutes, 60 images each – AP and lateral)

WHAT DOES IT INVOLVE?

• Static images are obtained – usually AP and lateral (5 minutes each)

• These images are used for marking with a Cobalt-57 tipped “pen”

• Static oblique images (further 5 minutes) obtained to confirm position and depth

• Position checked with gamma probe

Melanoma site

SN

Melanoma site

SN

2nd

Melanoma site

SN

SN

SN

Melanoma site

SN

SN

SPECT CT

• A new dual headed camera with SPECT CT (Single Photon Emission Computed Tomography CT) was installed in 2005

• SPECT CT provides SPECT images, low dose CT for anatomical localisation and fused images

• This adds considerably to the time taken and the radiation dose, but has apparently proven invaluable in terms of surgery

OUR USE OF SPECT CT

• Initially for localisation in head and neck melanomas to give additional information

• Localisation where node is obscured by injection site in one plane

• Localisation where 2 nodes are apparently close together

• Position in large patients (eg: above or below inguinal ligament)

• Localisation where position seems abnormal (eg: nodes found close to scapula rather than in axilla)

NUMBERS

SPECT CT NUMBERS

SPECT CT BY AREA

PROGRESS

• Increasing numbers mean a Consultant may not always be immediately available in the department

• Consequently 3 radionuclide radiographers (M. Caffrey, J. Winfield, J. Kerr) have trained to mark straightforward nodes

• Consultant always involved for head and neck and other nodes needing SPECT CT as well as any others which seem technically difficult