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
Pancreatic neuroendocrine tumours - octrepotide sensitivity
Wide variability in sensitivity by cell type: Gastrinomas typically high, insulinomas often low (50-60%)
Pancreatic NET findings
○ In-111DTPA-D-Pheoctreotide(Octreoscan):
Radiolabeled derivative of octreotide, binds to
somatostatin receptor (subtypes 2, 5, rarely 3)
○ Determination of somatostatin-receptor status to guide
octreotide therapy
○ Selection of patients with metastatic tumors for peptide
receptor radionuclide therapy (PRRT)
Other somatostatin receptor avid tumours
Pituitary adenoma; adrenal medullary tumors; paraganglioma; benign and malignant thyroid tissue; Merkel cell; melanoma; carcinoid; small cell lung cancer; non-pancreatic neuroendocrine carcinoma; meningioma; well-differentiated glial-derived tumor; breast, prostate, renal carcinomas; lymphoma, granuloma, infection, and inflammation
Ddx pancreatic NET
Panc ductal adenocarcinoma
Mucinous or serous pancreatic tumour
Mets
Pheo/paraganglioma findings
I-123 MIBG scintigraphy
○ Use for occult, ectopic, recurrent, metastatic tumors
○ Patient should discontinue drugs that interfere with
MIBG for 48-72 hrs prior
• F-18FDGPET
○ Sensitivity similar to MIBG, best for malignant pheochromocytoma/paragangliomas
Pheo 10% rule
10% familial 10% bilateral 10% malignant 10% in children 10% not associated with HTN
Malignancy diagnosed by presence of metastatic deposits, not by presence of local invasion
Ddx pheo/paraganglioma
Other neuroendocrine tumours (MIBG + in carcinoma, neuroblastoma, ganglioneuroma)
Adrenal adenoma/myelolipoma - uptake < liver on MIBG/FDG
ACC
Adrenal mets
Pheo or paraganglioma associations
MEN IIA/IIB NF VHL TS SW
Medullary thyroid CA findings
• Somatostatin receptor scintigraphy
○ Uptake in solid, usually well-circumscribed mass in
thyroid gland; ± calcifications; nodal and distant
metastases
• F-18FDGPET/CT:Sensitivity70-100%,specificity79-90%
• Tc-99m sestamibi or tetrofosmin scintigraphy: Sensitivity
25-40%, specificity 100%
• Not iodine avid: Scanning and treatment with radioiodine not effective
Ddx medullary thyroid CA
Follicular adenoma
MNG
Parathyroid adenoma
Papillary/follicular thyroid CA
Ovarian CA findings
○ FDG PET/CT
– FDG-avid ovarian mass (SUV>3)
– ± hypermetabolic lymphadenopathy, diffuse
peritoneal involvement
– ± distant metastases (usually liver/lung) or malignant
pleural effusion
– PET has difficulty with differentiation of benign vs.
malignant w/ borderline elevated SUV
– Physiologic uptake of ovary is highest in early
secretory phase, best to image just after menstruation to
Cervical CA findings
○ FDG PET/CT
– Intense FDG activity in primary cervical mass
– Variable uptake in uterus, vagina, and parametria,
depending on spread
– Pelvic and paraaortic FDG-avid lymphadenopathy
– Distant metastases in lung, liver, bone
Prostate mets
Metastases are usually axial, then follow distribution of
red bone marrow
○ Vertebra and rib involvement common due to tumor cell
dissemination from prostate through Batson venous plexus
• Uptake on Tc-99m MDP bone scan has low specificity for metastatic disease when PSA < 10 ng/mL in patient not on antiandrogen therapy
□ Recommended for symptomatic patients or
asymptomatic patients at risk for occult metastases
□ Patients considered at risk for occult metastases
include those with PSA > 20 ng/mL or PSA > 10 with
T2-T4 primary or Gleason score > 8
Malignant pleural mesothelioma
F-18 FDGPET/CT
○ Directs biopsy to hypermetabolic pleuralplaques
○ Most complete staging when compared with CT
○ Hypermetabolic pleural masses &/ or pleural rind with
associated pleural effusion
○ Canbeassociatedwithhypermetabolicevidenceof
direct invasion or distant metastatic disease
Malignant pleural mesothelioma ddx
Inflammatory - absbestos, talc, organized empyema
Other neoplasms - mets, fibrous pleural tumour, lymphoma
NSCLC ddx
• Granulomatous disease
○ Symmetrical mildly FDG-avid hilar & mediastinal nodes
• Pneumonia
○ FDG uptake can be high, but more rapid temporal
change
• Mediastinal mass
○ Consider small cell lungcancer, lymphoma
• Hamartoma
○ Typically low FDG activity, popcorn calcification
• Pulmonary infarct
○ FDG uptake as great as with lung cancer
• Carcinoid
○ MaynotbehighlyFDGavid
• Small cell carcinoma
○ Requires biopsyt odifferentiate
NSCLC cell types
○ Squamous cell carcinoma, large cell carcinoma,
adenocarcinoma, and adenocarcinoma in situ
• Best diagnostic clue
○ Irregular mass in bronchus or lung parenchyma
– Squamous cell carcinomas tend to be more central in location
– Adenocarcinomas tend to occur more peripherally
– Large cell carcinomas tend to be peripheral
False - PET for NSCLC
Tumor with low metabolic rate (low-grade
adenoCA, adenocarcinoma in situ, carcinoid), tumor < 10 mm, “stunned” tumor post therapy, high serum glucose (competition)
Associated findings NSCLC
Recurrent laryngeal nerve: Hoarseness
Superior vena cave syndrome
Small cell lung CA findings
○ Hilar mass with bulky mediastinal adenopathy
○ Often infiltrates submucosa, obstructs bronchus
○ May have small primary tumor
Thymoma/thymic carcinoma findings
○ Thymoma
– Low-risk thymoma: TypesA, AB, and B1
– High-risk thymomas: Types B2 and B3
○ Thymic carcinoma
- Higheruptake of F-18 FDG with thymic carcinomas in comparison to thymomas
- Thymic carcinoma has more heterogeneous uptake
- Thymic rebound may have increased F-18 FDGuptake
SPN ddx
FDG positive: Malignant - Primary lung - Metastases - Lymphoma
Benign
Infection
Inflammation (sarcoid, RA, granulomatosis with polyangitis)
Round atelectasis
Variable to low FDG uptake
Malignant
- Primary lung (adencarcinoma spectrum, carcinoid)
- Mets (mucinous adenocarcinoma, RCC, prostate, hepatocellular)
FDG negative
Inactive granulomatous disease
Hamartoma
AVM
Papillary and follicular thyroid Ca findings
I-123 whole-body scan
○ I-123 localizes to thyroid tissue that transports and
organifies iodine
○ Detects thyroid remnant, lymphadenopathy, and distant
metastatic or recurrent disease
○ 159 keV gamma rays more optimal for LEAP collimators
○ Physiologic uptake in salivary glands, stomach, lactating
breasts
○ Renal excretion
I-131 whole-body scan
○ I-131 is gamma (364 keV) and beta (0.606 MeV) emitter
○ Higher radiation burden as compared to I-123
○ Possible risk of thyroid stunning prior to I-131ablation
due to high-energy beta
○ Imaging characteristics not as good as I-123
F-18 FDG PET/CT
○ Uptake of radioactive glucose analogue into thyroid
tissuethrough GLUT1 transporter
○ Can be used to evaluate patients with tumors that are
not iodine avid and have elevated thyroglobulin levels (>
10 ng/mL)
Tc-99m MDP bone scan
○ For skeletal survey if bone metastases suspected
Thyroid procotol
TSH stimulation
□ Thyroid hormone withdrawal for 3weeks (goal TSH
> 30 mU/L)
□ Thyrogen stimulation: Thyrogen (human recombinant TSH) stimulation with 0.9 mg IM on 2 consecutive days
– Low-iodine diet: Usually followed for 7-14 days to increase uptake of radioactive iodine by thyroid tissue
RCC findings
Iso or hypermetabolic mass on FDG PET
Transitional cell carcinoma
F-18 FDG PET/CT
– Focal increased FDG activity in primary tumor, regional
nodes, and distant metastases
– Best for staging and monitoring for recurrenceq
Ewing Sarcoma findings
• Destructive osseous lesion with associated soft tissue mass
• Femur is single most common site (~ 20%)
• > 85% in pelvis, extremities and ribs
– Long bones
□ Metadiaphyseal > diaphyseal
□ Proximal > distal
– Originate in medullary canal, spread outward
○ Extraosseous ES
– Paravertebral and lower extremity most common
MDP
• Tc-99m MDP bone scan shows increased uptake in tumor in all phases, but is not adequate for local staging (poor sensitivity for “skip lesions”)
• FDG PET/CT
○ Defines primary tumor better than MDP bones can
Ewing ddx
Other malignant bone primary (osteosarcoma, primary lymphoma)
Osteomyelitis
Benign bone tumours
Fracture
Bone mets (neuroblastoma, rhabdomyosarcoma)
PRRT - things to consider
Treat with Lu-177 dotatate if Krenning 3-4
Kidneys are dose limiting organs - need to protect with amino acids (inhibits proximal tubular resportion)
Marrow suppression
Liver failure
MIBG therapy - considerations
Thyroid blockade - SSKI day before, day of, and continue 10-15 days after
Discontinue interfering meds
Slow administration - anaphlyaxis
Liver - intra-arterial therapy
Yttrium 90 microspheres (non-resectable primary and secondary lesions)
Must assess lung shunt ratio with MAA
- if < 10%, no reduction
- if 10-15%, 20% reduction
- if 15-20%, 40% reduction
Neuroendocrine tumour types
Adrenal/sympathetic chain:
- Neuroblastoma
- Pheochromoctytoma
- Paraganglioma
Gastropancreatic neuroendocine tumours:
- Carcinoid, neuroendocrine carcinoma
- Pancreatic endocrine
Medullary thyroid cancer
Syndromes MEN I, II, VHL, NF
Pheochromocytoma biochemical testing
Plasma/urine metanephrines
Plasma/urine catecholamines
Paraganglioma types
Carotid body
Glomus tympanicum - middle ear mass; pulsatile tinnitis
Glomus jugulare -
Glomus vagale
Octreotide or MIBG avid
Ddx always includes meningioma or neuroendocrine tumour met (as both octreotide avid) +/- pituitary adenoma
MEN 2
2A: MTC, pheo, hyperparathyroidism
2B: MTC, pheo, multiple neuromas
Gastropancreatic NETs classification
Grade 1 NET: < 2 mitoses/HPF, <3% ki-index
Grade 2 NET: 2-20 mitosees/HPF, 3-20% Ki-index
Grade 3 NET: >20, >20
Scintimammography false postive
Fibroadenoma
Malignant tumours other than breast CA
Blood work carcinoid
Chromogranin A levels elevated
5-HIAA levels elevated
Other octreotide avid tumours
Carcinoid Gastrinoma Glucagonoma Pheochromocytoma Neuroblastoma
MTC
Small cell lung cancer Lymphoma Breast cancer Astrocytoma Meningioma Pituitary adenoma Thymoma
FDG prep
NPO 4 hrs; ideally 8-12
Blood sugar < 10
Laryngeal nerve injury
Paralysis/Decreased FDG on that side
Compensatory hypermetabolism on other side
Ddx: malignancy/infection/inflammation on the hypermetabolic side
Thallium for brain spect
Distinguish radiation necrosis from recurrent disease
Distinguish lymphoma/other malignancy from toxoplasmosis
MIBG uptake
NB
Pheochromoctyoma
Carcinoid
MTC
Pheochromocytoma markers
MIBG is not screening test
Need elevated serum or urinary catecholamine levels
Benign pelvic uptake FDG in females
CLC Dermoid cyst Diverticulitis Leoiomyoma Fibroma/thecoma Ureteric Endometriosis
Gallium avid tumours
HL NHL Melanoma Sarcoma Hepatoma Lung CA
+ sarcoid, infection
Diffuse marrow uptake FDG
Benign marrow stimulatiomn
Widespread marrow-based tumour
Altered biodistribution
Ddx hypermetabolic solitary nodule
Primary lung CA
Pulmonary metastases
Inflammation/Infection (TB, histo, sarcoid)
Hypermetabolic focus pancreas
Panc adenocarcinoma
Focal pancreatitis
Metastasis
FDG avid focus parotid gland
Primary salivary gland tumour
Focal parotatitis
Ddx increased abdominal uptake on octreotide study
Neuroendocrine tumour
Other malignancy expressing somatostatin receptors (melanoma, breast)
Inflammatory conditions expressing somatostatin receptors (granulomatous disease)
