Management Of Small Bowel Tumors Flashcards
What sex group and age range are most affected by small bowel tumors?
Men and present in the sixth and seventh decade of life
What is the percentage of new cancers that occur in the small bowel?
2%
What are the best imaging modalities for small bowel?
SBFT, enteroclysis, CT scan, u/s, MRI, upper endoscopy, push endoscopy, capsule endoscopy and double ballon endoscopy
What are the most common symptoms of small bowel tumors?
Abdominal pain, distention, nausea, vomiting, obstruction, and occult bleeding
What percentage of patients have advanced disease at diagnosis?
More than 50%
What is the most common small bowel malignancy?
Carcinoid tumor
What percentage of GI carcinoids spread to the mesentery?
40-80%
What is the most common symptom in carcinoid and why does it occur?
Obstruction, due to fibrosis around the tumor, which can cause adhesions of intestinal loops and stricturing of the bowel
What percentage of pts with GI carcinoid present with carcinoid syndrome?
10%
What is the chemical diagnosis test for carcinoid?
5-HIAA 24hr urine sample or serum chromogranin A
What is octreotide scan?
Useful for initial imaging study, radio labeled octreotide taken up by somatostatin receptors that are over expressed by carcinoid tumors. Sensitivity 80-90%. Also helps to predict tumor response to treatment with somatostatin receptor analogs
What is the treatment for carcinoid syndrome?
Surgical resection with extensive lymphadenectomy
What is the role of surgery in metastatic disease?
The role of surgery is not as well defined but resection of bowel, mesenteric tumors, lymph node and hepatic metastases and fibrotic areas can improve quality of life and symptoms. For this to occur, approximately 90% of disease has to be removed
How else do you treat metastatic disease?
Long acting somatostatin analogs
What is carcinoid crisis?
Excessive cutaneous flushing, hyperthermia, shock, arrhythmias, and bronchial obstruction. Seen perioperatively if pt given somatostatin preoperatively.
What is the overall 5-yr survival for carcinoid tumors?
60-65%, ranging from 96% for stage I to 43% for stage IV
What are negative predictors for carcinoid?
Older than 55, male, tumor greater than 1 cm and distant mets
Do pts with carcinoid tumors require lifelong surveillance?
Yes, because 85% of pts are expected to have liver mets
What is the second most common small bowel malignancy?
Adenocarcinoma
What is the most common location for adenocarcinoma?
Duodenum, though in pts younger than 50, jejunum is more prevalent
What are some diseases associated with small bowel adenocarcinoma?
Crohn’s disease, celiac disease, familial adenomatous polyp oasis, hereditary nonpolyposis colorectal cancer and Peutz-Jeghers syndrome
What percentage of pts have advanced disease at the time of diagnosis for adenocarcinoma?
More than 50%, 24% with distant mets and 33% with nodal involvement
How do these tumors appear on imaging?
Adenocarcinoma appear to have apple core lesions with severe narrowing of the lumen of the bowel
What is the primary treatment of adenocarcinoma?
Surgical resection, which is the only chance for cure.
What is the surgery of choice?
For proximal tumors, pancreaticoduodenectomy are necessary. As for distal tumors, segmental resection and lymphadenectomy is adequate
How are intraabdominal mets treated in adenocarcinoma?
If causing obstruction or hemorrhage, palliation should be done with stenting or placement of gastric or gastrojejunostomy tubes
What is the 5-yr survival for adenocarcinoma?
30% with a median survival of 20 months
What are the negative predicting factors in adenocarcinoma?
Male, older than 55, tumor located I’m the duodenum or ileum, and the presence of distant mets
What percentage of GIST tumors are located in the small bowel?
25%; 50% located in the stomach; when in the small bowel, they are most likely seen in the jejunum
Do GIST tumors usually metastasize to the lymph nodes?
No, they usually metastasize to the liver and serosal nodules. Also rarely have extraabdominal spread
What are the common presenting symptoms?
Obstruction, abdominal discomfort, early satiety and abdominal distention due to the space-occupying nature of the lesions
Are preoperatively biopsies necessary in GiST?
No, because biopsies increase the risk of tumor hemorrhage and dissemination, but may be appropriate when planning neoadjuvant therapy
What is the characteristic CT scan finding?
Smooth and well-circumscribed mass in the bowel wall that demonstrates exophytic growth and may demonstrate central necrosis or hemorrhage
What is the important surgical tenet for excising GIST tumors?
Complete en bloc gross resection with an intact pseudocapsule to avoid rupture and tumor dissemination. There is some evidence that those with tumor rupture after complete resection have a shortened survival compared to those without rupture
Can laparoscopy be useful in these tumors?
It can be used for tumors less than 5cm but data looking at outcomes are limited
When should imatinib be considered?
Preoperatively for extremely large tumors that would have improved resection with reduced size, and for unresectable or metastatic tumors
What is the follow up after starting imatinib?
Follow up imaging 2-4 weeks after initiating therapy for less extensive GIST and 3 months for unresectable or metastatic lesions
What percentage of patients develop tumor recurrence within 5 years?
50%
Which segment of patients should be treated for a minimum of 12 months with imatinib?
Those with intermediate to high risk GIST. It should also be given postoperatively to pts with incomplete resection, recurrent disease and metastatic disease
What is the 5-year overall survival for pts with GISt?
40%
What are the negative predicting factors of GiST?
Tumor size, mitotic index per high-powered field, male, age greater then 55, mets, poorly differentiated tumors and involved margins
What are the subtypes of primary non-Hodgkin lymphomas in the small intestines?
Diffuse, large B-cell lymphoma (most common), mucosa-associated lymphoid tissue (MALT) lymphoma and immunoproliferative small intestinal disease
What location in the small bowel is most prevalent with lymphom?
The ileum
What is the most common malignancy affecting the mesentery?
Lymphoma
What patients have a higher risk of lymphom?
Celiac disease (20 fold relative risk), HIV and low CD4 count
How do these tumors look on Ct scan?
Large, homogenous mass, which show less contrast enhancement compared to other malignancies
What is required for diagnosis of lymphoma?
Tissue biopsy
What is the optimal treatment for GI lymphoma?
Localized, early-stage lymphomas can undergo surgical resection; more advanced tumors have limited role for surgical resection except for obtaining tissue for diagnosis and palliating any complications. Also chemotherapy has variable cure rates
What is the 5-year survival for GI lymphomas?
Across all subtypes, 50%
What are the factors that negatively affect prognosis?
Male and older than 75
What are the majority of tumors seen in the small bowel?
Metastases, most often from melanoma, lung and breast cancer
What is the most common presentation of metastases to the small bowel?
SBO, but ascites, mesenteric ischemia, perforation and bleeding are also seen
What is the risk of malignant transformation in adenomas
Size greater than 1 cm, high grade dysplasia, and villious subtype
What is the most common location for adenomas?
Duodenum
What is the recurrence rate after excision for adenomas?
Up to 30% at 5 yrs, so these pts have regular endoscopic surveillance
What is important to know about lipomas of the small bowel?
Little to malignant potential; seen as homogenous mass on ct and as smooth, radiolucent, well-circumscribed intramural masses whose size and form change with peristalsis and pressure on barium studies; lipomas greater than 2cm or symptomatic should be resected
How should hamartomas be treated?
They should be excised when they are symptomatic (abdominal pain, intussusception, obstruction or bleeding) or polyps that are rapidly expanding
How can hemiangiomas be treated?
Local excision, segmental resection, endoscopic sclerotherapy or angiographic embolization
