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 Note: the term "carcinoids" is outdated: these tumors are now more accurately called "neuroendocrine tumors."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.

LCIS may be treated with close clinical follow-up and mammographic screening, tamoxifen or related hormone controlling drugs to reduce the risk of developing cancer, or bilateral prophylactic mastectomy. Some surgeons consider bilateral prophylactic mastectomy to be overly aggressive treatment except for certain high-risk cases.

Since many, if not most, anal cancers derive from HPV infections, and since the HPV vaccine before exposure to HPV prevents infection by some strains of the virus and has been shown to reduce the incidence of potentially precancerous lesions, scientists surmise that HPV vaccination may reduce the incidence of anal cancer.

On 22 December 2010, the U.S. Food and Drug Administration approved Gardasil vaccine to prevent anal cancer and pre-cancerous lesions in males and females aged 9 to 26 years. The vaccine has been used before to help prevent cervical, vulvar, and vaginal cancer, and associated lesions caused by HPV types 6, 11, 16, and 18 in women.

LCIS (lobular neoplasia is considered pre-cancerous) is an indicator (marker) identifying women with an increased risk of developing invasive breast cancer. This risk extends more than 20 years. Most of the risk relates to subsequent invasive ductal carcinoma rather than to invasive lobular carcinoma.

While older studies have shown that the increased risk is equal for both breasts, a more recent study suggests that the ipsilateral (same side) breast may be at greater risk.

Current dietary recommendations to prevent colorectal cancer include increasing the consumption of whole grains, fruits and vegetables, and reducing the intake of red meat and processed meats. Higher physical activity is also recommended. Physical exercise is associated with a modest reduction in colon but not rectal cancer risk. High levels of physical activity reduce the risk of colon cancer by about 21%. Sitting regularly for prolonged periods is associated with higher mortality from colon cancer. The risk is not negated by regular exercise, though it is lowered. The evidence for any protective effect conferred by fiber and fruits and vegetables is, however, poor. The risk of colon cancer can be reduced by maintaining a normal body weight.

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.

Chemotherapy has relatively poor curative efficacy in SRCC patients and overall survival rates are lower compared to patients with more typical cancer pathology. SRCC cancers are usually diagnosed during the late stages of the disease, so the tumors generally spread more aggressively than non-signet cancers, making treatment challenging. In the future, case studies indicate that bone marrow metastases will likely play a larger role in the diagnosis and management of signet ring cell gastric cancer.

In SRCC of the stomach, removal of the stomach cancer is the treatment of choice. There is no combination of chemotherapy which is clearly superior to others, but most active regimens include 5-Fluorouracil (5-FU), Cisplatin, and/or Etoposide. Some newer agents, including Taxol and Gemcitabine (Gemzar) are under investigation.

In a single case study of a patient with SRCC of the bladder with recurrent metastases, the patient exhibited a treatment response to palliative FOLFOX-6 chemotherapy.

Transitional cell carcinoma (TCC) can be very difficult to treat. Treatment for localized stage TCC is surgical resection of the tumor, but recurrence is common. Some patients are given mitomycin into the bladder either as a one-off dose in the immediate post-operative period (within 24 hrs) or a few weeks after the surgery as a six dose regimen.

Localized/early TCC can also be treated with infusions of BCG into the bladder. These are given weekly for either 6 weeks (induction course) or 3 weeks (maintenance/booster dose). Side effects include a small chance of developing systemic tuberculosis or the patient becoming sensitized to the BCG causing severe intolerance and a possible reduction in bladder volume due to scarring.

In patients with evidence of early muscular invasion, radical curative surgery in the form of a cysto-prostatectomy usually with lymph node sampling can also be performed. In such patients, a bowel loop is often used to create either a "neo-bladder" or an "ileal conduit" which act as a place for the storage of urine before it is evacuated from the body either via the urethra or a urostomy respectively.

There are different opinions on the best treatment of DCIS. Surgical removal, with or without additional radiation therapy or tamoxifen, is the recommended treatment for DCIS by the National Cancer Institute. Surgery may be either a breast-conserving lumpectomy or a mastectomy (complete or partial removal of the affected breast). If a lumpectomy is used it is often combined with radiation therapy. Tamoxifen may be used as hormonal therapy if the cells show estrogen receptor positivity. Chemotherapy is not needed for DCIS since the disease is noninvasive.

While surgery reduces the risk of subsequent cancer, many people never develop cancer even without treatment and there associated side effects. There is no evidence comparing surgery with watchful waiting and some feel watchful waiting may be a reasonable option in certain cases.

First-line chemotherapy regimens for advanced or metastatic TCC consists of gemcitabine and cisplatin) (GC) or a combination of methotrexate, vinblastine, adriamycin, and cisplatin (MVAC).

Taxanes or vinflunine have been used as second-line therapy (after progression on a platinum containing chemotherapy).

Immunotherapy such as pembrolizumab is often used as second-line therapy for metastatic urothelial carcinoma that has progressed despite treatment with GC or MVAC.

In May 2016 FDA granted accelerated approval to atezolizumab for locally advanced or metastatic urothelial carcinoma treatment after failure of cisplatin-based chemotherapy. The confirmatory trial (to convert the accelerated approval into a full approval) failed to achieve its primary endpoint of overall survival.

Aspirin and celecoxib appear to decrease the risk of colorectal cancer in those at high risk. Aspirin is recommended in those who are 50 to 60 years old, do not have an increased risk of bleeding, and are at risk for cardiovascular disease to prevent colorectal cancer. It is not recommended in those at average risk. There is tentative evidence for calcium supplementation, but it is not sufficient to make a recommendation. Vitamin D intake and blood levels are associated with a lower risk of colon cancer.

10 to 20% of patients treated for anal cancer will develop distant metastatic disease following treatment. Metastatic or recurrent anal cancer is difficult to treat, and usually requires chemotherapy. Radiation is also employed to palliate specific locations of disease that may be causing symptoms. Chemotherapy commonly used is similar to other squamous cell epithelial neoplasms, such as platinum analogues, anthracyclines such as doxorubicin, and antimetabolites such as 5-FU and capecitabine. JD Hainsworth developed a protocol that includes Taxol and Carboplatinum along with 5-FU. Median survival rates for patients with distant metastases ranges from 8 to 34 months.

There are several treatment options for penile cancer, depending on staging. They include surgery, radiation therapy, chemotherapy, and biological therapy. The most common treatment is one of five types of surgery:

- Wide local excision—the tumor and some surrounding healthy tissue are removed

- Microsurgery—surgery performed with a microscope is used to remove the tumor and as little healthy tissue as possible

- Laser surgery—laser light is used to burn or cut away cancerous cells

- Circumcision—cancerous foreskin is removed

- Amputation (penectomy)—a partial or total removal of the penis, and possibly the associated lymph nodes.

Radiation therapy is usually used adjuvantly with surgery to reduce the risk of recurrence. With earlier stages of penile cancer, a combination of topical chemotherapy and less invasive surgery may be used. More advanced stages of penile cancer usually require a combination of surgery, radiation and chemotherapy.

In addition to all the above, treatment of the underlying disease like brucellosis, is important to limit disease recurrence.

Use of radiation therapy after lumpectomy provides equivalent survival rates to mastectomy, although there is a slightly higher risk of recurrent disease in the same breast in the form of further DCIS or invasive breast cancer. Systematic reviews (including a Cochrane review) indicate that the addition of radiation therapy to lumpectomy reduces recurrence of DCIS or later onset of invasive breast cancer in comparison with breast-conserving surgery alone, without affecting mortality. The Cochrane review did not find any evidence that the radiation therapy had any long-term toxic effects. While the authors caution that longer follow-up will be required before a definitive conclusion can be reached regarding long-term toxicity, they point out that ongoing technical improvements should further restrict radiation exposure in healthy tissues. They do recommend that comprehensive information on potential side effects is given to women who receive this treatment. The addition of radiation therapy to lumpectomy appears to reduce the risk of local recurrence to approximately 12%, of which approximately half will be DCIS and half will be invasive breast cancer; the risk of recurrence is 1% for women undergoing mastectomy.

Primary signet-ring cell carcinoma of the urinary bladder is extremely rare and patient survival is very poor and occurs mainly in men ages 38 to 83. However, one such patient treated with a radical cystectomy followed by combined S-1 and Cisplatin adjuvant chemotherapy did demonstrate promising long-term survival of 90 months.

Carcinoma "in situ" is, by definition, a localized phenomenon, with no potential for metastasis unless it progresses into cancer. Therefore, its removal eliminates the risk of subsequent progression into a life-threatening condition.

Some forms of CIS (e.g., colon polyps and polypoid tumours of the bladder) can be removed using an endoscope, without conventional surgical resection. Dysplasia of the uterine cervix is removed by excision (cutting it out) or by burning with a laser. Bowen's disease of the skin is removed by excision. Other forms require major surgery, the best known being intraductal carcinoma of the breast (also treated with radiotherapy). One of the most dangerous forms of CIS is the "pneumonic form" of BAC of the lung, which can require extensive surgical removal of large parts of the lung. When too large, it often cannot be completely removed, with eventual disease progression and death of the patient.

Treatment of invasive carcinoma of no special type (NST) depends on the size of the mass (size of the tumor measured in its longest direction):

- <4 cm mass: surgery to remove the main tumor mass and to sample the lymph nodes in the axilla. The stage of the tumor is ascertained after this first surgery. Adjuvant therapy (i.e., treatment after surgery) may include a combination of chemotherapy, radiotherapy, hormonal therapy (e.g., tamoxifen) and/or targeted therapy (e.g., trastuzumab). More surgery is occasionally needed to complete the removal of the initial tumor or to remove recurrences.

- 4 cm or larger mass: modified (a less aggressive form of radical mastectomy) radical mastectomy (because any malignant mass in excess of 4 cm in size exceeds the criteria for a lumpectomy) along with sampling of the lymph nodes in the axilla.

The treatment options offered to an individual patient are determined by the form, stage and location of the cancer, and also by the age, history of prior disease and general health of the patient. Not all patients are treated the same way.

Prognosis can range considerably for patients, depending where on the scale they have been staged. Generally speaking, the earlier the cancer is diagnosed, the better the prognosis. The overall 5-year survival rate for all stages of penile cancer is about 50%.

While cancer is generally considered a disease of old age, children can also develop cancer. In contrast to adults, carcinomas are exceptionally rare in children..

The two biggest risk factors for ovarian carcinoma are age and family history.

Treatment is variable, both due to its rarity and to its frequently slow-growing nature. Treatment ranges from watchful waiting to debulking and hyperthermic intraperitoneal chemotherapy (HIPEC, also called intraperitoneal hyperthermic chemotherapy, IPHC) with cytoreductive surgery.

Surgery remains the front-line therapy for HNPCC. There is an ongoing controversy over the benefit of 5-fluorouracil-based adjuvant therapies for HNPCC-related colorectal tumours, particularly those in stages I and II.

When BAC recurs after surgery, the recurrences are local in about three-quarters of cases, a rate higher than other forms of NSCLC, which tends to recur distantly.

Invasive carcinoma of no special type (NST) also known as invasive ductal carcinoma or ductal NOS and previously known as invasive ductal carcinoma, not otherwise specified (NOS) is a group of breast cancers that do not have the "specific differentiating features". Those that have these features belong to other types.

In this group are: pleomorphic carcinoma, carcinoma with osteoclast-like stromal giant cells, carcinoma with choriocarcinomatous features, and carcinoma with melanotic features. It is a diagnosis of exclusion, which means that for the diagnosis to be made all the other specific types must be ruled out.

Adenocarcinoma (; plural adenocarcinomas or adenocarcinomata ) is a type of cancerous tumor that can occur in several parts of the body. It is defined as neoplasia of epithelial tissue that has glandular origin, glandular characteristics, or both. Adenocarcinomas are part of the larger grouping of carcinomas, but are also sometimes called by more precise terms omitting the word, where these exist. Thus invasive ductal carcinoma, the most common form of breast cancer, is adenocarcinoma but does not use the term in its name—however, esophageal adenocarcinoma does to distinguish it from the other common type of esophageal cancer, esophageal squamous cell carcinoma. Several of the most common forms of cancer are adenocarcinomas, and the various sorts of adenocarcinoma vary greatly in all their aspects, so that few useful generalizations can be made about them.

In the most specific usage (narrowest sense), the glandular origin or traits are exocrine; endocrine gland tumors, such as a VIPoma, an insulinoma, or a pheochromocytoma, are typically not referred to as adenocarcinomas but rather are often called neuroendocrine tumors. Epithelial tissue sometimes includes, but is not limited to, the surface layer of skin, glands, and a variety of other tissue that lines the cavities and organs of the body. Epithelial tissue can be derived embryologically from any of the germ layers (ectoderm, endoderm, or mesoderm). To be classified as adenocarcinoma, the cells do not necessarily need to be part of a gland, as long as they have secretory properties. Adenocarcinoma is the malignant counterpart to adenoma, which is the benign form of such tumors. Sometimes adenomas transform into adenocarcinomas, but most do not.

Well differentiated adenocarcinomas tend to resemble the glandular tissue that they are derived from, while poorly differentiated adenocarcinomas may not. By staining the cells from a biopsy, a pathologist can determine whether the tumor is an adenocarcinoma or some other type of cancer. Adenocarcinomas can arise in many tissues of the body owing to the ubiquitous nature of glands within the body, and, more fundamentally, to the potency of epithelial cells. While each gland may not be secreting the same substance, as long as there is an exocrine function to the cell, it is considered glandular and its malignant form is therefore named adenocarcinoma.

The treatment of choice in any patient with BAC is complete surgical resection, typically via lobectomy or pneumonectomy, with concurrent ipsilateral lymphadenectomy.

Non-mucinous BACs are highly associated with classical EGFR mutations, and thus are often responsive to targeted chemotherapy with erlotinib and gefitinib. K-ras mutations are rare in nm-BAC.

Mucinous BAC, in contrast, is much more highly associated with K-ras mutations and wild-type EGFR, and are thus usually insensitive to the EGFR tyrosine kinase inhibitors. In fact, there is some evidence that suggests that the administration of EGFR-pathway inhibitors to patients with K-ras mutated BACs may even be harmful.