Category Archives: Cancer

What is the RET proto-oncogene?

RET Proto-Oncogene

From an insurance standpoint on RET proto-oncogene testing for MTC – found on the internet:

Aetna considers diagnostic testing for germline point mutations in the RET gene medically necessary for members with apparently sporadic medullary thyroid carcinoma.

What is a proto-oncogene?

A proto-oncogene is a normal gene which can become an oncogene due to mutations or increased expression.

Types of Thyroid Cancer

Five main types of Thyroid Cancer

  1. Papillary Carcinoma (80%)
  2. Follicular Carcinoma (10%)
  3. Medullary Carcinoma (5%)
  4. Hurthle Cell Carcinoma (4%)
  5. Anaplastic/Undifferentiated Carcinoma (1-2%)

P’s of Papillary Thyroid Cancer:

  • Popular (most common type – 80%)
  • Psammoma bodies
  • Palpable Lymph Nodes – common
  • Positive Iodine 131 uptake
  • Positive Prognosis
  • Postoperative Iodine 131 to diagnose / treat metastasis if a total thyroidectomy was done.

F’s of Follicular Cancer of the Thyroid

  • Far away metastasis (spreads hematogenously)
  • FNA NOT (FNA cannot be done to diagnosis Follicular Cancer of the thyroid
  • Female predominance (3:1)

M’s of Medullary Cancer of the Thyroid

  • MEN II (Multiple Endocrine Neoplasia type II)
  • aMyloid
  • Median Lymph Node dissection
  • Modified neck dissection if lateral nodes are positive
  • Secretes Calcitonin
  • Stimulated by Pentagastrin
  • Cancer of the Thyroid C cells = parafollicular cells

Calcitonin (tumor marker for MTC)

  • Reduces blood levels of Calcium
  • Opposed the effects of PTH (parathyroid hormone)
  • Calcitonin is used as a tumor marker for medullary thyroid cancer (MTC)


  • Pentagastrin has effects like gastrin
  • Pentagastrin is used as a stimulation test to elevate serotonin levels and cause symptoms of carcinoid syndrome, provoking flushing.
  • Pentagastrin has been used to stimulate ectopic gastric mucosa for the detection of Meckels diverticulum by nuclear medicine.
  • Pentagastrin-stimulated calcitonin test is a diagnostic test for MTC (Medullary carcinoma of the thyroid).  In patients with suspected MTC but borderline levels of calcitonin, injecting pentagastrin will cause calcitonin levels to rise tremendously.


Thyroid Anatomy
Thyroid Anatomy

Picture from:



Neck Anatomical Zones for Cancer and Trauma

Neck Zones for Cancer

When thinking of neck zones, there are those zones used in trauma and there are those used for cancer surgery.

The neck zones or levels depicted here are for cancer surgery.  Lymph nodes or neck masses in these areas are described using these locations:

anatomical zones of neck
Picture copied from internet

  • In patients presenting with solid neck masses – those masses associated with the thyroid move with swallowing.  Those in levels 3,4, and 5 do not move with swallowing.
  • Metastatic lymph nodes found in level 6 – could come from thyroid.
  • U/S and FNA should be performed after exam/history for Solid Neck Mass.
  • With well differentiated thyroid cancers, there is a high rate of cervical metastasis particularly with papillary cancers.
  • With lateral lymph nodes involved in thyroid cancer, survival rate is not improved significantly with LN dissection in the neck for patients older than 60 years old or for men with a 4 cm or larger well differentiated cancer.
  • Prophylactic lymph node dissections does not seem to improve survival with patients undergoing thyroid cancer treatment.
  • If thyroid tumor is small with documented (U/S) lateral lymph nodes.  There is a benefit to dissecting level 3 or 4 lymph nodes (lymph node dissection or modified dissection) in the younger patient.

Trauma neck zones

picture copied from internet:



Oncology Surgery Highlights – Notes

Surgical Oncology – Cancer

  • Melanoma in-situ.  5mm resection margin is needed.  (only 5 mm).  In Situ = outer layer of the skin only (epidermis only)
  • Currently Melanoma SLN positive mandates lymphadenectomy in melanoma.
  • Patients with Familial Adenomatous Polyposis and Desmoids, ~10% of the tumors will have a very rapid and aggressive course.  In FAP, there is a nearly 100 percent risk of colorectal cancer in the absence of treatment for polyposis.
  • Uncontrolled local recurrence is the main cause of death with retroperitoneal sarcomas.
  • Radiation therapy generally has not been shown to help low grade completely resected extremity sarcomas.
  • Flat colorectal polyps:  ~25% contain high grade dysplasia.
  • SLN in colorectal cancer increases the accuracy of lymph node cancer status but often does not change the operation.
  • Stage III colorectal cancer, all chemotherapy regimens seem to improve outcome. Another related topic:  Stage 4 colon cancer.
  • T2 colorectal lesions have a local recurrence rate of about 22%.  With resection you induce a 20% local recurrence rate on a T2 cancer which had a 80% cure rate before resection.  Salvage operations for local recurrence are associated with a 40-60% cure rate.  Therefore, there is a 20% chance that a T2 patient survival will be reduced by doing a local resection (ie. transanal).
  • Rectal cancers.  Size of an adenocarcinoma after initial preoperative chemotherapy is more predictive than the initial size of the tumor.
  • More advanced Gallbladder tumors, stage II, should be treated with a completion radical cholecystectomy – partial hepatectomies of the gallbladder bed with hepatoduodenal lymphadenectomy.  Stage II:  This means that cancer has grown through the muscle layer of the gallbladder wall and into the connective tissue underneath. It has not spread outside the gallbladder. Stage 2 in the TNM stages is the same as T2, N0, M0.
  • Metastasis found in remote lymph nodes in gallbladder cancer portend a poor prognocis.
  • PET scans doesn’t help distinguish acute or chronic cholecystitis vs. gallbladder cancer.
  • Endoscopic ultrasound should be used often in evaluating patients with pancreatic cysts.
  • If a pancreatic cyst wall has any nodularity then it may be malignant or on it’s way.
  • Pancreatic cancer, the risk of malignancy is lower for side branch intraductal papillary mucinous neoplasm than for main duct IPMNS.
  • Statistically, patients with pancreatic intraductal papillary mucinous neoplasms have an increased risk of colon and breast cancer.
  • Jaundice is not an emergency.  First understand the root cause before reflexively draining the bile duct.
  • Parenchymal metastasis from a primary tumor such as lung metasis or liver metastasis, etc – those pts tend to do very poorly with peritoneal chemotherapy.
  • GIST (Gastro Intestinal Stromal Tumors) – standard therapy is gleevec (IMATINIB).  Metastatic disease may have resistance to the drug
  • For patients with Colon cancer primary with metastasis to the liver with < or = 6 tumors in the liver where  R0 resection (resection for cure) can be done, then these patients are reasonable candidates for resection surgery.

Ectopic ACTH production

Ectopic ACTH Syndrome

Also known as EAS

Sources of Ectopic ACTH production.

  • Lung = most common cause.
  • Thymus
  • Thyroid – Medullary carcinoma
  • Ovary
  • Adrenal Gland – pheochromocytoma
  • Liver
  • Pancreas
  • Other neuroendocrine cancers

Difference between Cushings syndrome and Cushings disease

  • Cushings syndrome is cortisol excess from any cause.
  • Cushings disease is cortisol excess by pituitary ACTH over-secretion

Presentation found on the internet regarding Ectopic ACTH production:

What is a Gastrointestinal Stromal Tumor (GIST)

GIST – Gastrointestinal Stromal Tumor

  • GISTs may be malignant or benign
  • More common in the stomach and small intestine but can be found anywhere along the GI tract.
  • Begins in cells called th interstitial cells of Cajal (ICC) – considered the pacemakers of the GI tract
  • GIST may have a genetic component.  Neurofibromatosis type 1 is linked to GIST.
  • Partial resections are usually adequate with GIST treatment with negative margins.  Formal gastrectomy is not usually necessary, nor is partial gastrectomy with nodal dissection.  Organ sparing approaches are usually appropriate.