Blue Book: Primary Unknown (Cancer of unknown origin)

Question 1

What percentage of proven malignancies can the primary site remain unknown despite standard investigations?

Answer 1

10%

Question 2

For the following queue cards. Name the common primaries that would be found at the given site of metastases.

Liver

Answer 2

Breast, Lung, Colon,

Question 3

Lung

Answer 3

Breast, Lung, Kidney

Question 4

Brain

Answer 4

Breast, Lung, Melanoma

Question 5

Bone

Answer 5

Breast, Bronchus, Kidney, Prostate, Thyroid

Question 6

Peritoneal

Answer 6

Ovary, GI tract (esp stomach), pancreas

Question 7

High cervical nodes

Answer 7

head & neck, thyroid, lung

Question 8

lower cervical/supra-clavicular

Answer 8

head & neck, lung, breast, GI tract

Question 9

Axillary

Answer 9

breast, lung, melanoma

Question 10

Inguinal

Answer 10

ovary, prostate, ano-recta,, vulva

Question 11

What is the common histology of carcinomas of unknown origin?

Answer 11

Adenocarciomas or undifferentiated tumours

Question 12

Most likely primary for:

1) Adenocarcinoma
2) Squamous

Answer 12

1) GI tract (including pancreas), breast, ovary, lung.

2) Lung, head and neck.

Question 13

Name the likely diagnosis based on the following ‘syndromes’:

a) Young men + disease in midline (para-aortic/mediastinal/neck/brain nodes)
b) Women with axillary or thoracic nodes.
c) women with abdominal carcinomatosis
d) men with boney mets
e) multiple moderate size abnormal nodal sites

When these syndromes are identified what management should occur?

Answer 13

a) germ cell tumour (curable with chemo!)- used tumour markers
b) breast cancer
c) ovarian cancer
d) prostate cancer (do rectal exam & PSA order bone scan)
e) lymphoma

Do simple investigations only taking a few days, then start empirical treatment for the given cancer.

Question 14

What standard investigations can be offered when clinically appropriate?
(Theres loads)

Answer 14

• Full clinical assessment and examination to include breast, nodal, skin, genital,
rectal and pelvic examination
• Full blood count, urea, electrolytes and creatinine; liver function tests; calcium;
urinalysis, lactate dehydrogenase
• Chest x-ray
• Myeloma screen (when there are isolated or multiple lytic bone lesions)
• Symptom-directed endoscopy
• CT scan of chest, abdomen and pelvis
• Prostate specific antigen (PSA) in men
• Cancer antigen 125 (CA125) in women with peritoneal malignancy or ascites
• Alpha-fetoprotein (AFP) and human chorionic gonadotrophin (hCG) (especially in
the presence of midline nodal disease)
• Testicular ultrasound in men with presentations compatible with germ cell
tumours
• Biopsy and standard histological examination, with immunohistochemistry
where necessary, to distinguish carcinoma from other malignant diagnoses

Question 15

Management

Answer 15

Chemotherapy for adult solid tumour + GI tumours

Question 16

Prognosis of cancer of unknown origin

Poor prognostic features

Answer 16

3-4 months.
5 year survival is less than 10%

male, ↑N. of organ sites, adenocarcinoma histology, hepatic involvement.