<unk>  was first described in the published literature by Sir George Thos. Beatson, an English surgeon, in 1913. Development of surgical sciences revolutionized cancer care,<unk>  was not an exception. Introduction of  chemotherapy agents such as 5-fluorouracil (5-FU),  irinotecan, oxaliplatin, vascular endothelial growth factor receptor inhibitors (bevacizumab), epidermal growth factor receptor inhibitors (cetuximab and panitumumab), aflibercept, regorafenib, inhibitor of angiogenic tyrosine kinases (including the VEGF receptors 1, 2,and 3), capecitabine as well as introduction of intraperitoneal chemotherapy including hyperthermic intraperitoneal chemotherapyadvanced<unk>  treatment.  Development of new Imaging modalities such as CT scan, MRI as well as specific imaging modalities such as somatostatin scintigraphy  also transfigured approaching to the patients with<unk> . Genetic studies introduced novel horizons in approaching patients with<unk> .
There are two major subtypes of<unk> , adenocarcinomas and carcinoid tumors. While carcinoid tumors arises from enterochromaffin cells (Kulchitsky cells), which are secretory cells that are normally involved in neuroendocrine hormonal secretions, adenocarcinomas are the result of mutations in mucus producing epithelial cells. Their physiology, pathophysiology, genetic pathways, prognosis as well as epidemiology are different and hence, discussed separately. The progression to adenocarcinoma usually involves the KRAS, APC, TP53, and RAF pathways, While β-catenin, NF1, and MEN1 genes are major contributors of carcinoid tumors progression. Prevalence, risk factors, age distribution as well as prognosis are different in the two major types of<unk> eal cancers, adenocarcinoma and carcinoid tumors. The estimated prevalence of<unk>  is approximately 0.12 cases per 100,000 individuals in the United States.The incidence of<unk>  increases with age; meanwhile, patients with carcinoid tumors are generally younger than their adenocarcinoma counterparts. The median age at diagnosis is 65 years for adenocarcinoma, compared to t 32-43 years (range, 6 to 80 years) for carcinoid tumors. Common risk factors in the development of<unk>  are a combination of environmental and genetic factors. Common risk factors in the development of<unk>  include age, sex, smoking, familial cancer disorders such as  MEN1 Syndrome and HNPCC, as well as long standing chronic inflammatory disorders such as ulcerative colitis and Crohn's disease.
Because of the location and size of<unk> , most of the patients with<unk>  may be initially asymptomatic. Early clinical features might include periodical unspecific abdominal pain, bloating, and nausea. Most of<unk>  cases are discovered after surgical or histological evaluation of a patient with acute<unk> itis, or are an accidental finding in imaging studies for the other reasons. If left untreated, the majority of patients with<unk>  may progress to develop peritoneal carcinomatosis and metastasis. Prognosis is generally excellent and good in carcinoid tumors and adenocarcinoma respectively. Prognostic factors including tumor stage, tumor size, histologic as well genetic characteristics of<unk> eal tumors were discussed in details. Either CT-scan or MRI are diagnostic study of choice for<unk> . Both MRI (particularly diffusion weighted MRI) and CT scan has been recommended as method of choice for disease staging. Histopathology is the gold standard test for the diagnosis as well as classification of<unk> s. Patients with<unk>  usually appear normal, might present with acute<unk> itis or carcinoid syndrome.  Laboratory findings consistent with the diagnosis of carcinoid tumors include , Chromogranin A (CgA), 5-HIAA (5-hydroxyindoleacetic acid) as well as Ki67. Some patients with colonic type adenocarcinoma may have elevated concentration of CEA and CA 19-9.
Abdominal CT scan is pretty helpful in the diagnosis and management of<unk> . Findings on CT scan suggestive of<unk>  include soft tissue thickening, wall irregularity, calcification, internal septations, preappendiceal fat stranding as well as intraperitoneal free fluid. CT scan is also one of the best imaging modalities to assess disease burden, metastatic lesions as well as disease stage. Diffusion weighted MRI has been shown to be the modality of choice for peritoneal carcinomatosis evaluation. Positron emission tomography (PET) and scintigraphy are among other imaging modalities that may be helpful in the diagnosis and management of<unk> .<unk>  may also be diagnosed using scintigraphy, capsule endoscopy, enteroscopy, positron emission tomography (PET). Chromogranin A (CgA) and 5-HIAA (5-hydroxyindoleacetic acid) are among biochemical markers that might represent level of malignant cells activity in carcinoid syndrome.
Medical therapy in<unk>  could be either supportive, palliative, or curative. While carcinoid tumors rarely need chemotherapy, systemic chemotherapy as well as hyperthermic intraperitoneal chemotherapy plus/minus early postoperative intraperitoneal chemotherapy (EPIC) and/or concomitant intravenous chemotherapy are mainstream of medical treatment in adenocarcinoma of<unk> . Medical therapy is generally administered to control the symptoms in patients with carcinoid tumors and carcinoid syndrome.
Surgery is the mainstay of treatment for<unk> . The feasibility as well as determining the appropriate plan of surgery depends on the stage of<unk>  at diagnosis. Tumor size plays the crucial role in determining the need for further surgery. Consensus based effective measures for the secondary prevention of<unk>  include follow up history and physical examination, tumor marker measurements like CEA, CA-125, CA 19-9, follow up imaging studies, carcinoid tumor markers such serotonin, and specific imaging studies such as octreotide scintigraphy.
Appendix cancer
Anal cancer
Stomach cancer
Oral cancer
Bladder cancer
Breast-ovarian cancer
Small intestine cancer
Colorectal cancer