Oral Exam - Oncology Flashcards
Poorly FDG-avid breast cancers
Lobular or tubular carcinoma
○ Typically low FDG uptake 2° to low-grade tumor
○ With aggressive behavior, mays how ↑ FDG uptake
DCIS
○ Variable linear/branching areas of FDGuptake
Primary malignant breast cancer
PET/CT
○ Sensitivities reported inrange of 79-90% ;specificity74- 80%
○ 5-7mm lesions routinely detected, especially if prone PET/CT used
PEM
○ Breast-specific imaging device
○ Optimized for small body parts,with higher sensitivity
than PET (1-2 mm for PEM; 4-6 mm for PET)
○ SensitivitycomparabletoMRandhigherthanPET(93%
vs. 68%)
MBI/BSGI ○ Emerging technology ○ Breast-specificimagingdevice ○ Achievegreaterresolutionbydecreasingdeadspace between breast and imaging surface
Tc-99m MIBI
○ No longer used due to inferior results compared to PET/CT
Sensitivityof 76-90%; poor sensitivity(<50%) for smallor low-grade malignancies
– Lesion uptake dependent on increased blood flow,
mitochondrial activity and concentration in tumor
Thallium(Tl)-201
○ No longer used due to higher sensitivity with modalities
listed above
○ Poor sensitivity for lesions < 1.5 cm (40-60%)
○ Poor sensitivity for low-grade malignancy
Ddx breast abnormality
Benign breast lesion
Infection/inflammation
Trauma/surgery
Lactation
Brain mets - hypermetabolic on PET
Lung, breast, colorectal, head and neck, melanoma, thyroid
Brain mets - hypometabolic on PET
Mucinous, adenocarcinoma, renal cell carcinoma
Brain met ddx on PET
Abscess
INfarct
Primary brain tumour - benign or malignant
Epilepsy
Radiation necrosis vs tumour progression on Brain
Low uptake favors radiation necrosis or low-grade tumor
Thallium-201 or Tc-99m sestamibi SPECT
○ Radiation necrosis typically shows decreased uptake
○ Recurrent glioma typically shows increased uptake
Melanoma - most common mets
○ Skin, subcutaneous tissue, and lymph nodes: 50-75% ○ Lungs: 70-87% ○ Liver: 54-77% ○ Brain: 36-54% ○ Bone: 23-49% ○ GI tract: 26-58%
Timing of esophageal PET
Indicated to evaluate response to therapy
○ After neoadjuvant therapy, prior to surgery
○ Should be done 5-6 weeks after completion of therapy
• Indicated to detect recurrence
○ High sensitivity for detection of localre current tumoror
regional nodal disease
Ddx esophageal malignancy on PET
Esophagitis - infectious or inflammatory
Intramural primary esophageal tumour
Metastatic or adjacent tumour
Esophageal primaries that are FDG avid
Adenocarcinoma (Barret, reflux, motility disorders) and squamous cell carcinoma (smoking, alcohol) are F- 18FDG avid
□ F-18 FDG uptake in squamous cell carcinoma >
adenocarcinoma
Esophageal node evaluation
– Does not allow reliable differentiation between N0 and N1 disease, due to intense uptake by primary lesion masking adjacent metastatic nodes
– Regional nodes are considered to be cervical to celiac stations
– T1-T3±N+ are resectable
Ddx abnormal gastric FDG activity
Gastric Carcinoma
Gastric GIST
Physiologic - low level activity, non-focal
Gastritis/gastric ulcer - mild to moderate uptake
Gastric lymphoma - usually diffuse invovlement with adenopathy
Crohn’s - rarely affects stomach
Metastatic spread of CRC
Lymphatic (mostcommon) spread follows major venous outflow from involved segment
□ Colon - pericolic nodes, then superior and inferior mesenteric nodes
□ Upper rectum drains to superior rectal nodes, then
inferior mesenteric nodes
□ Lower rectum followssamedrainagepatternas
upper rectum and also middle rectal nodes, then
internal iliac nodes
Hematogenous spread
□ Via portal system to liver (most common site for distant metastases)
□ Lung
Peritoneal spread
□ Direct peritoneal seeding→peritoneal carcinomatosis
Salivary gland tumours and PET
F-18FDG PET/CT
○ Cannot reliably differentiate benign vs. malignant
salivary gland neoplasia
○ Hypermetabolic lesions on F-18FDGPET/CT have~30%
false-positive rate for malignancy (mostly due to high
uptake in Warthin tumor)
Any incidentally detected salivary gland neoplasm should
be evaluated by otolaryngology, whether cold, warm, or hot
Ddx salivary gland lesion
○ Parotid carcinoma (most common site of salivary gland
cancer) - different cell types, almost always FDG avid
○ Benign mixed tumors/pleomorphicadenoma - less FDG avid than malignancy or Warthin
○ Warthin tumor - positive on FDG and Tc99 pertechnetate SG studies; smoking history; often multiple
○ Primary lymphoma
SCC of head and neck locations
Nasopharynx, larynx, hypopharynx, oralcavity,
oropharynx, nasal cavity, paranasal sinuses, salivary glands, thyroid gland, and unknown primary
SCC of head and neck - PET findings
○ Best diagnostic clue
– Intensely FDG-avid, enlarged or necrotic lymphnodes (LNs) in neck on F-18 FDG PET/CT
Location
– Look for primary lesion along mucosal surfaces and
evidence for nodal or distant spread
– LN metastases in expected drainage pattern based on
primary tumor location
– Commonly involves base of tongue, tonsils, or
adenoids
SCC head and neck protocol advice
○ Scan with arms down on F-18FDG PET/CT to avoid beam
hardening artifact; use neck immobilization device
○ F-18 FDG PET/CT is superior to conventional imaging
modalities for radiation treatment planning, allowing for improved tumor coverage and sparing of normal tissues
SCC lymph nodes ddx
Inflammatory - dual time imaging at 3-6 hours helpful. CA retains more FDG for longer than inflammatory tissues.
Thyroid or Melanoma metastases
Abscess
Lymphoma - associated mucosal lesion or necrotic nodes favours SCC met
Brown fat - Measure HU usingCT; diagnostic if HU measure -50 to -150
Head and Neck lymph nodes
Level 1A = submental
Level 1B = submandibular
Level 1 drains anterior oral cavity, lip, sinonasal
Level 2A/2B
Inferior margin of hyoid, posterior margin submandib, SCM muslcles
Level 2 drains Oropharynx, posterior oral cavity, supraglottic larynx, and parotid gland
Level 3
Inferior margin of hyoid, inferior margin of cricoid
Level 4
Inferior margin of cricoid, clavicle
Drains subglottic, thyroid, and cervical esophagus
Level 5
Posterior border of SCM,clavicle; VA/VB inferior margin of cricoid
Drains nasopharynx, skin (neckor occipital scalp)
Level 6
Medial margins of carotid arteries, inferior margin of hyoid, superior aspect of manubrium
Drains subglottic, thyroid, and cervical esophagus
Level 7/superior mediastinal
Superior aspect of manubrium, innominate vein
Supraclavicular nodes
At or caudal to level of clavicle and lateral to medial edge of carotid arteries
Retropharyngeal nodes
Within 2cm of skullbase medial to carotid arteries
Parotid nodes
Primary drainage site: Skin of scalp, orbit, and
nasopharynx
HCC PET performance
□ Uptake in small tumors difficult to visualize on F-18
FDG PET/CT because of physiological F-18 FDG
uptake
□ Well-differentiated HCC isointense to liver on F-18
FDG PET/CT (low GLUT1 and high G6Pase
expression); higher SUV if poorly differentiated
□ Variable uptake with intrahepatic CCA
DDx liver lesion on PET
Met Abscess HCC Cholangiocarcinoma GB CA
Hodgkin’s lymphoma - time to wait before PET
○ 6-8 weeks after chemotherapy or surgery
○ 8-12 weeks after radiation therapy
○ 2-4 weeks after (G-CSF)
Interim or post-therapy PET/CT: Deauville criteria
– Grades the most intense uptake (SUV) in initial site of disease on interim or end-of-treatment PET/CT
– 1: No uptake
– 2: Uptake ≤ mediastinal bloodpool
– 3: Uptake > mediastinal blood pool but ≤ liver
– 4: Uptake moderately higher thanliver
– 5:Uptakemarkedlyhigherthanliver&/ornewlesions
– X: New areas of uptake unlikely to be related to
lymphoma
○ Score of 1 and 2: Complete metabolic response (CMR)
○ Score of 3: Likely a CMR
Score 4 and 5: Residual hypermetabolic disease
Ann Arbour staging with Lugano modifiers
Modifiers
○ A or B: Absence (“A”) or presence (“B”) of B symptoms
○ E: Relevant only for limited extranodal disease in
absence of nodal involvement (IE) or in patients with stage II disease and direct extension to a non-nodal site (IIE)
StageI
– 1nodeorgroupofadjacentnodes(1lymphnode region) (I)
StageII
– 2ormorenodalregionsonthesamesideofthe
diaphragm (II)
Stage IV
– Nodal disease + noncontiguous extranodal
involvement
NHL
Hematogenous spread of NHL is unpredictable in
comparison to contiguous spread of HL
Report findings according to Deauville criteria (5-point scale)
– Score 1 and 2: Complete metabolic response (CMR)
– Score 3: Likely CMR
– Score 4 and 5: Residual disease
– Score 5 with no decrease in uptake or new FDG-avid
disease: Treatment failure
FDG avid NHL
Diffuse large B-cell DLBCL, Burkitt lymphoma,
anaplastic large cell, natural killer/T-cell, high-grade
follicular, adult T cell, peripheral T cell
Low grade minimally FDG avid lymphoma
– Chronic lymphocytic leukemia/small lymphocytic
(CLL), Waldenström macroglobulinemia, cutaneous T cell (mycosis fungoides), marginal zone (MZL), mantle cell, low-grade follicular
Carcinoid syndrome
Flushing, diarrhea, telangiectasia, and asthma
Secretes serotonin, which is metabolized to 5- hydroxyindoleacetic acid (5-HIAA)
Lab values to check in NET
Elevated serum chromogranin A (sensitivity80%)
Elevated 24-hour urinary 5-HIAA
High Ki-67 implies worse survival
Number of mitoses/HPF
NET imaging
Somatostatin receptor imaging (SRI)
– Indium-111 octreoscan
– High percentage of lesions > 1.5cm positive
□ 4hr: Whole body anterior/posterior planar
optional; consider targeted SPECT based on history
and planar imaging (low bowel excretion then)
□ 24hr: Whole body anterior/posterior planar;
targeted SPECT, SPECT usually best at 24 hours
□ 48hr:Whole body anterior/posterior planar
optional; consider targeted SPECT
□ Image with large FOV at symmetric 20% energy
windows over 173 keV and 247 keV photopeaks of
In-111
NET other imaging options
FDG PET or I131 MIBG
Treatment options for NET
• Surgery
○ Curative resection of smaller masses
○ Debulk tumor to ↓symptoms and improve survival
- Systemic chemotherapy with alpha interferon and cytotoxic agents
- Livermetastases
○ Resection,radiofrequencyablation,cryotherapy,and
chemoembolization
• Somatostatinanalogs
○ Symptomaticblockade,butsubjecttotachyphylaxis
○ Radiolabelled analogs to target metastases