Surgery, if feasible, is the only curative therapy. If the tumor has metastasized (most commonly, to the liver) and is considered incurable, there are some promising treatment modalities, such as radiolabeled octreotide (e.g. Lutetium (Lu) DOTA-octreotate) or the radiopharmaceutical 131I-mIBG (meta iodo benzyl guanidine) for arresting the growth of the tumors and prolonging survival in patients with liver metastases, though these are currently experimental.

Chemotherapy is of little benefit and is generally not indicated. Octreotide or Lanreotide (somatostatin analogues) may decrease the secretory activity of the carcinoid, and may also have an anti-proliferative effect. Interferon treatment is also effective, and usually combined with somatostatin analogues.

As the metastatic potential of a coincidental carcinoid is probably low, the current recommendation is for follow up in 3 months with CT or MRI, labs for tumor markers such as serotonin, and a history and physical, with annual physicals thereafter.

In general, treatment for PanNET encompasses the same array of options as other neuroendocrine tumors, as discussed in that main article. However, there are some specific differences, which are discussed here.

In functioning PanNETs, octreotide is usually recommended prior to biopsy or surgery but is generally avoided in insulinomas to avoid profound hypoglycemia.

PanNETs in MEN1 are often multiple, and thus require different treatment and surveillance strategies.

Some PanNETs are more responsive to chemotherapy than are gastroenteric carcinoid tumors. Several agents have shown activity. In well differentiated PanNETs, chemotherapy is generally reserved for when there are no other treatment options. Combinations of several medicines have been used, such as doxorubicin with streptozocin and fluorouracil (5-FU) and capecitabine with temozolomide. Although marginally effective in well-differentiated PETs, cisplatin with etoposide has some activity in poorly differentiated neuroendocrine cancers (PDNECs), particularly if the PDNEC has an extremely high Ki-67 score of over 50%.

Several targeted therapy agents have been approved in PanNETs by the FDA based on improved progression-free survival (PFS):

- everolimus (Afinitor) is labeled for treatment of progressive neuroendocrine tumors of pancreatic origin in patients with unresectable, locally advanced or metastatic disease. The safety and effectiveness of everolimus in carcinoid tumors have not been established.

- sunitinib (Sutent) is labeled for treatment of progressive, well-differentiated pancreatic neuroendocrine tumors in patients with unresectable locally advanced or metastatic disease. Sutent also has approval from the European Commission for the treatment of 'unresectable or metastatic, well-differentiated pancreatic neuroendocrine tumors with disease progression in adults'. A phase III study of sunitinib treatment in well differentiated pNET that had worsened within the past 12 months (either advanced or metastatic disease) showed that sunitinib treatment improved progression-free survival (11.4 months vs. 5.5 months), overall survival, and the objective response rate (9.3% vs. 0.0%) when compared with placebo.

In localized, resectable adult GISTs, if anatomically and physiologically feasible, surgery is the primary treatment of choice. Surgery can be potentially curative, but watchful waiting may be considered in small tumors in carefully selected situations. Post-surgical adjuvant treatment may be recommended. Lymph node metastases are rare, and routine removal of lymph nodes is typically not necessary. Laparoscopic surgery, a minimally invasive abdominal surgery using telescopes and specialized instruments, has been shown to be effective for removal of these tumors without needing large incisions. The clinical issues of exact surgical indications for tumor size are controversial. The decision of appropriate laparoscopic surgery is affected by tumor size, location, and growth pattern.

Radiotherapy has not historically been effective for GISTs and GISTs do not respond to most chemotherapy medications, with responses in less than 5%. However, three medications have been identified for clinical benefit in GIST: imatinib, sunitinib, and regorafenib.

Imatinib (Glivec/Gleevec), an orally administered drug initially marketed for chronic myelogenous leukemia based on bcr-abl inhibition, also inhibits both "c-kit" tyrosine kinase mutations and PDGFRA mutations other than D842V, is useful in treating GISTs in several situations. Imatinib has been used in selected neoadjuvant settings. In the adjuvant treatment setting, the majority of GIST tumors are cured by surgery, and do not need adjuvant therapy. However, a substantial proportion of GIST tumors have a high risk of recurrence as estimated by a number of validated risk stratification schemes, and can be considered for adjuvant therapy. The selection criteria underpinning the decision for possible use of imatinib in these settings include a risk assessment based on pathological factors such as tumor size, mitotic rate, and location can be used to predict the risk of recurrence in GIST patients. Tumors <2 cm with a mitotic rate of <5/50 HPF have been shown to have lower risk of recurrence than larger or more aggressive tumors. Following surgical resection of GISTs, adjuvant treatment with imatinib reduces the risk of disease recurrence in higher risk groups. In selected higher risk adjuvant situations, imatinib is recommended for 3 years.

Imatinib was approved for metastatic and unresectable GIST by the US FDA, February 1, 2002. The two-year survival of patients with advanced disease has risen to 75–80% following imatinib treatment.

If resistance to imatinib is encountered, the multiple tyrosine kinase inhibitor sunitinib (marketed as Sutent) can be considered.

The effectiveness of imatinib and sunitinib depend on the genotype. cKIT- and PDGFRA-mutation negative GIST tumors are usually resistant to treatment with imatinib as is neurofibromatosis-1-associated wild-type GIST. A specific subtype of PDGFRA-mutation, D842V, is also insensitive to imatinib.

Regorafenib (Stivarga) was FDA approved in 2013 for advanced GISTs that cannot be surgically removed and that no longer respond to imatinib (Gleevec) and sunitinib (Sutent).

Several issues help define appropriate treatment of a neuroendocrine tumor, including its location, invasiveness, hormone secretion, and metastasis. Treatments may be aimed at curing the disease or at relieving symptoms (palliation). Observation may be feasible for non-functioning low grade neuroendocrine tumors. If the tumor is locally advanced or has metastasized, but is nonetheless slowly growing, treatment that relieves symptoms may often be preferred over immediate challenging surgeries.

Intermediate and high grade tumors (noncarcinoids) are usually best treated by various early interventions (active therapy) rather than observation (wait-and-see approach).

Treatments have improved over the past several decades, and outcomes are improving. In malignant carcinoid tumors with carcinoid syndrome, the median survival has improved from two years to more than eight years.

Detailed guidelines for managing neuroendocrine tumors are available from ESMO, NCCN and a UK panel. The NCI has guidelines for several categories of NET: islet cell tumors of the pancreas, gastrointestinal carcinoids, Merkel cell tumors and pheochromocytoma/paraganglioma.

Even if the tumor has advanced and metastasized, making curative surgery infeasible, surgery often has a role in neuroendocrine cancers for palliation of symptoms and possibly increased lifespan.

Cholecystectomy is recommended if there is a consideration of long-term treatment with somatostatin analogs.

The main treatment modalities are surgery, embolization and radiotherapy.

This is considered to be a hybrid between an exocrine and endocrine tumor derived from crypt cells of the appendix. Histologically, it forms clusters of goblet cells containing mucin with a minor admixture of Paneth cells and endocrine cells. The growth pattern is distinctive: typically producing a concentric band of tumor nests interspersed among the muscle and stroma of the appendiceal wall extending up the shaft of the appendix. This makes the lesion difficult to suspect grossly and difficult to measure. Small tumor nests may be camouflaged amongst the muscle or in periappendiceal fat; cytokeratin preparations best demonstrate the tumor cells; mucin stains are also helpful in identifying them. They behave in a more aggressive manner than do classical appendiceal carcinoids. Spread is usually to regional lymph nodes, peritoneum, and particularly the ovary. They do not produce sufficient hormonal substances to cause the carcinoid or other endocrine syndromes. In fact, they more closely resemble exocrine than endocrine tumors. The term 'crypt cell carcinoma' has been used for them, and though perhaps more accurate than considering them carcinoids, has not been a successful competitor.

Pancreatic neuroendocrine tumors (PanNETs, PETs, or PNETs), often referred to as "islet cell tumors", or "pancreatic endocrine tumors" are neuroendocrine neoplasms that arise from cells of the endocrine (hormonal) and nervous system within the pancreas.

PanNETs are a type of neuroendocrine tumor, representing about one third of gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Many PanNETs are benign, while some are malignant. Aggressive PanNET tumors have traditionally been termed "islet cell carcinoma".

PanNETs are quite distinct from the usual form of pancreatic cancer, the majority of which are adenocarcinomas, which arises in the exocrine pancreas. Only 1 or 2% of clinically significant pancreas neoplasms are PanNETs.

Genetic changes are very high in SCLC and LCNEC, but usually low for TC, intermediate for AC.

GISTs occur in 10-20 per one million people. The true incidence might be higher, as novel laboratory methods are much more sensitive in diagnosing GISTs. The estimated incidence of GIST in the United States is approximately 5000 cases annually. This makes GIST the most common form of sarcoma, which constitutes more than 70 types of cancer.

The majority of GISTs present at ages 50–70 years. Across most of the age spectrum, the incidence of GIST is similar in men and women.

Adult GISTs are rare before age 40. Pediatric GISTs are considered to be biologically distinct. Unlike GISTs at other ages, pediatric GISTs are more common in girls and young women. They appear to lack oncogenic activating tyrosine kinase mutations in both KIT and PDGFRA. Pediatric GISTs are treated differently than adult GIST. Although the generally accepted definition of pediatric GIST is a tumor that is diagnosed at the age of 18 years or younger, "pediatric-type" GISTs can be seen in adults, which affects risk assessment, the role of lymph node resection, and choice of therapy.

The preferred treatment for esthesioneuroblastoma is surgery followed by radiotherapy to prevent reoccurrence of the tumor.

Chemotherapy is used in a multimodality treatment plan generally for more advanced, unresectable or reoccurring tumors. Cyclophosphamide, vincristine and doxorubicin have been used as neoadjuvant chemotherapy drugs for grade C esthesioneuroblastoma before surgical resection, producing fair outcomes. Cisplatin and etoposide are often used to treat esthesioneuroblastoma as neoadjuvants or adjuvants with radiotherapy or surgery. Study results are promising. In advanced stage esthesioneuroblastoma in pediatric patients, where surgery is no longer possible, aggressive chemotherapy and radiotherapy has resulted in some tumor control and long term survival.

The Stehlin Foundation currently offers DSRCT patients the opportunity to send samples of their tumors free of charge for testing. Research scientists are growing the samples on nude mice and testing various chemical agents to find which are most effective against the individual's tumor.

Patients with advanced DSRCT may qualify to participate in clinical trials that are researching new drugs to treat the disease.

The prognosis for DSRCT remains poor. Prognosis depends upon the stage of the cancer. Because the disease can be misdiagnosed or remain undetected, tumors frequently grow large within the abdomen and metastasize or seed to other parts of the body.

There is no known organ or area of origin. DSRCT can metastasize through lymph nodes or the blood stream. Sites of metastasis include the spleen, diaphragm, liver, large and small intestine, lungs, central nervous system, bones, uterus, bladder, genitals, abdominal cavity, and the brain.

A multi-modality approach of high-dose chemotherapy, aggressive surgical resection, radiation, and stem cell rescue improves survival for some patients. Reports have indicated that patients will initially respond to first line chemotherapy and treatment but that relapse is common.

Some patients in remission or with inoperable tumor seem to benefit from long term low dose chemotherapy, turning DSRCT into a chronic disease.

Because LCLC-RP is so rare, no clinical trials have ever been conducted that specifically address treatment of this lung cancer variant. Because LCLC-RP is considered a form of non-small cell lung carcinoma (NSCLC), most physicians adhere to published NSCLC treatment guidelines in rhabdoid carcinoma cases. When possible, radical surgical resection with curative intent is the primary treatment of choice in early stage NSCLC's, and can be administered with or without adjuvant, neoadjuvant, or palliative chemotherapy and/or radiotherapy, depending on the disease stage and performance status of the individual patient.

In numerous clinical trials conducted in NSCLC, several different platinum-based chemotherapy regimens have been shown to be more-or-less equally effective. LCLC's, as a subtype of NSCLC, have traditionally been included in many of these clinical trials, and have been treated like other NSCLC's. More recent trials, however, have shown that some newer agents may have particular effectiveness in prolonging survival of LCLC patients. Pemetrexed, in particular, has shown significant reduction in the hazard ratio for death when used in patients with LCLC. Taxane-based (paclitaxel, docetaxel) chemotherapy was shown to induce a complete and sustained response in a liver metastasis in a case of LCC-RP. A later-appearing metastasis within mediastinal lymph nodes in the same case also showed a durable response to a taxane alone.

There have also been reports of rhabdoid carcinomas expressing vascular endothelial growth factor (VEGF), suggesting that targeted molecular therapy with VEGF blocking monoclonal antibodies such as bevacizumab may be active in these variants. However, evidence suggests that caution must be used when treating a cavitated rhabdoid tumor, one that contains significant components of squamous cell differentiation, or large tumors with containing major blood vessels, due to the potential high risk of life-threatening pulmonary hemorrhage.

A recent study reported a case wherein 2 courses of adjuvant therapy with cisplatin and paclitaxel, followed by oral gefitinib, were used after complete resection. The patient had had no recurrence 34 months later.

As large-volume LCLC-RP may show significant central necrosis and cavitation, prudence dictates that oncologists use extreme caution if contemplating the therapeutic use of bevacizumab, other anti-VEGF compounds, or anti-angiogenesis agents in general, which have been associated with a greatly increased risk of severe hemorrhage and hemoptysis that may be quickly fatal in cavatated pulmonary squamous cell carcinomas. Similar elevated risks have also been noted in tumors located near, or containing, large blood vessels.,

Small carcinoids (<2 cm) without features of malignancy may be treated by appendectomy if complete removal is possible. Other carcinoids and adenocarcinomas may require right hemicolectomy. Note: the term "carcinoids" is outdated: these tumors are now more accurately called "neuroendocrine tumors." For more information, see "appendiceal neuroendocrine tumors."

Pseudomyxoma peritonei treatment includes cytoreductive surgery which includes the removal of visible tumor and affected essential organs within the abdomen and pelvis. The peritoneal cavity is infused with heated chemotherapy known as HIPEC in an attempt to eradicate residual disease. The surgery may or may not be preceded or followed with intravenous chemotherapy or HIPEC.

The goblet cell carcinoid, abbreviated GCC and also known as crypt cell carcinoma and neuroendocrine tumour with goblet cell differentiation, is a rare biphasic gastrointestinal tract tumour that consists of a neuroendocrine component and a conventional carcinoma, histologically arising from Paneth cells.

10-year survival rates for mucinous tumors is excellent in the absence of invasion.

In the case of borderline tumors confined to the ovary and malignant tumors without invasion, the survival rates are 90% or greater. In invasive mucinous cystadenocarcinomas, the survival is approximately 30%

Surgery is the mainstay of treatment for clinically localized disease. In feasible cases, a partial cystectomy with "en-bloc" resection of the median umbilical ligament and umbilicus can achieve good results. In progressed stages, radiotherapy seems not to lead to sufficient response rates. However, chemotherapy regimes containing 5-FU (and Cisplatin) have been described to be useful in these cases. In recent years, targeted therapies have been demonstrated to be useful in reports of single cases. These agents included Sunitinib, Gefitinib, Bevacizumab and Cetuximab.

Because of its rarity, there have been no randomized clinical trials of treatment of GCCL, and all information available derives from small retrospective institutional series or multicenter metadata.

The median overall survival rate is about 50% in 5 years. Worse prognostic factors include the presence of residual tumor at the margin of the resection specimen (R+), invasion of the peritoneum and metastatic disease.

Wide, radical, complete surgical excision is the treatment of choice, with free surgical margins to achieve the best outcome and lowest chance of recurrence. Radiation is only used for palliation. In general, there is a good prognosis, although approximately 50% of patients die from disease within 3–10 years of presentation.

GCCs have an aggressive course compared to other appendiceal neuroendocrine tumours.

A study of primary malignacies in the United States found a rate of 0.12 cases per 1,000,000 population per year. Carcinoids that were not identified as malignant were not included in this data. Carcinoid is found in roughly 1 in 300 appendectomies for acute appendicitis.

A Hong Kong case series of 1492 appendectomies identified 17 neoplasms. Eight were carcinoids without specification of malignant features. Three cases of adenocarcinoma, and one each of cystadenocarcinoma, pseudomyxoma peritoneii, and metastasic carcinoma were identified. The remaining tumors were benign. It was previously believed that carcinoid tumors are the most common tumors of the appendix but now data from the SEER program show that mucinous adenocarcinomas are more common.

A gangliocytic paraganglioma, abbreviated GP, is a rare tumour that is typically found in the duodenum and consists of three components: (1) ganglion cells, (2) epithelioid cells (paraganglioma-like) and, (3) spindle cells (schwannoma-like).