Smoking is the most important risk factor for laryngeal cancer. Death from laryngeal cancer is 20 times more likely for heaviest smokers than for nonsmokers. Heavy chronic consumption of alcohol, particularly alcoholic spirits, is also significant. When combined, these two factors appear to have a synergistic effect.

Some other quoted risk factors are likely, in part, to be related to prolonged alcohol and tobacco consumption. These include low socioeconomic status, male sex, and age greater than 55 years.

People with a history of head and neck cancer are known to be at higher risk (about 25%) of developing a second cancer of the head, neck, or lung. This is mainly because in a significant proportion of these patients, the aerodigestive tract and lung epithelium have been exposed chronically to the carcinogenic effects of alcohol and tobacco. In this situation, a field change effect may occur, where the epithelial tissues start to become diffusely dysplastic with a reduced threshold for malignant change. This risk may be reduced by quitting alcohol and tobacco.

Smoking and alcohol abuse as the major risk factors. Viral causes has recently been taken under consideration as one of the risk factors. Viruses such as Epstein-Barr virus (EBV) (majorly involved in causing nasopharyngeal carcinoma) and human papilloma virus are included in this category. Chewing of betel nut ("Areca catechu") quid has been directly associated to cause oral cancers. It has also been stated under the FDA poisonous plant data base by the U.S Food and Drug Administration

An unbalanced diet, deficit in fruits and vegetables has shown to increase the risk of cancer.

Tobacco smoking is by far the main contributor to lung cancer. Cigarette smoke contains at least 73 known carcinogens, including benzo["a"]pyrene, NNK, 1,3-butadiene and a radioactive isotope of polonium, polonium-210. Across the developed world, 90% of lung cancer deaths in men during the year 2000 were attributed to smoking (70% for women). Smoking accounts for about 85% of lung cancer cases.

Passive smoking—the inhalation of smoke from another's smoking—is a cause of lung cancer in nonsmokers. A passive smoker can be defined as someone living or working with a smoker. Studies from the US, Europe and the UK have consistently shown a significantly increased risk among those exposed to passive smoke. Those who live with someone who smokes have a 20–30% increase in risk while those who work in an environment with secondhand smoke have a 16–19% increase in risk. Investigations of sidestream smoke suggest it is more dangerous than direct smoke. Passive smoking causes about 3,400 deaths from lung cancer each year in the USA.

Marijuana smoke contains many of the same carcinogens as those in tobacco smoke. However, the effect of smoking cannabis on lung cancer risk is not clear. A 2013 review did not find an increased risk from light to moderate use. A 2014 review found that smoking cannabis doubled the risk of lung cancer.

Most people with cancer of unknown primary origin have widely disseminated and incurable disease, although a few can be cured through treatment. With treatment, typical survival with CUP ranges from 6 to 16 months. Survival rates are lower in cases with visceral metastatic disease, ranging from 6 to 9 months. Survival rates are higher when the cancer is more limited to lymph nodes, pleura, or peritoneal metastasis, which ranges from 14 to 16 months. Long-term prognosis is somewhat better if a particular source of cancer is strongly suggested by clinical evidence.

Incidence is five in 100,000 (12,500 new cases per year) in the USA. The American Cancer Society estimated that 9,510 men and women (7,700 men and 1,810 women) would be diagnosed with and 3,740 men and women would die of laryngeal cancer in 2006.

Laryngeal cancer is listed as a "rare disease" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). This means that laryngeal cancer affects fewer than 200,000 people in the U.S.

CUP sometimes runs in families. It has been associated with familial lung, kidney, and colorectal cancers, which suggests that these sites may often be the origin of unidentifiable CUP cancers.

Outdoor air pollutants, especially chemicals released from the burning of fossil fuels, increase the risk of lung cancer. Fine particulates (PM) and sulfate aerosols, which may be released in traffic exhaust fumes, are associated with slightly increased risk. For nitrogen dioxide, an incremental increase of 10 parts per billion increases the risk of lung cancer by 14%. Outdoor air pollution is estimated to account for 1–2% of lung cancers.

Tentative evidence supports an increased risk of lung cancer from indoor air pollution related to the burning of wood, charcoal, dung or crop residue for cooking and heating. Women who are exposed to indoor coal smoke have about twice the risk and a number of the by-products of burning biomass are known or suspected carcinogens. This risk affects about 2.4 billion people globally, and is believed to account for 1.5% of lung cancer deaths.

Second most common primary anterior mediastinal mass in adults. Most are seen in the anterior compartment and rest are seen in middle compartment. Hodgkin's usually present in 40-50's with nodular sclerosing type (7), and non-Hodgkin's in all age groups. Can also be primary mediastinal B-cell lymphoma with exceptionally good prognosis. Common symptoms include fever, weight loss, night sweats, and compressive symptoms such as pain, dyspnea, wheezing, Superior vena cava syndrome, pleural effusions (10,11). Diagnosis usually by CT showing lobulated mass. Confirmation done by tissue biopsy of accompanying nodes if any, mediastinoscopy, mediastinotomy, or thoracotomy. FNA biopsy is usually not adequate. (12,13,14) Treatment of mediastinal Hodgkin's involves chemotherapy and/or radiation. 5 year survival is now around 75%. (15) Large-cell type may have somewhat better prognosis. Surgery is generally not performed because of invasive nature of tumor.

Of all cancers involving the same class of blood cell, 2% of cases are mediastinal large B cell lymphomas.

The mediastinum is the cavity that separates the lungs from the rest of the chest. It contains the heart, esophagus, trachea, thymus, and aorta. The mediastinum has three main parts: the anterior mediastinum (front), the middle mediastinum, and the posterior mediastinum (back).

The most common mediastinal masses are neurogenic tumors (20% of mediastinal tumors), usually found in the posterior mediastinum, followed by thymoma (15-20%) located in the anterior mediastinum.

Masses in the anterior portion of the mediastinum can include thymoma, lymphoma, pheochromocytoma, germ cell tumors including teratoma, thyroid tissue, and parathyroid lesions. Masses in this area are more likely to be malignant than those in other compartments.

Masses in the posterior portion of the mediastinum tend to be neurogenic in origin, and in adults tend to be of neural sheath origin including neurilemomas and neurofibromas.

Lung cancer typically spreads to the lymph nodes in the mediastinum.

A number of PPBs have shown trisomy 8 (17 out of 23 cases studied per the PPB registry). Trisomy 2 and p53 mutations/deletions have also been described.

An association with mutations in the DICER1 gene has been reported. Mutations in this gene are found in 2/3 cases.

Tonsillar carcinoma can be either HPV related or HPV unrelated. It is shown that cases which are HPV positive have a better prognosis than those with HPV negative oropharyngeal cancer.

Pleuropulmonary blastoma (PPB) is a rare cancer originating in the lung or pleural cavity. It occurs most often in infants and young children but also has been reported in adults. In a retrospective review of 204 children with lung tumors, pleuropulmonary blastoma and carcinoid tumor were the most common primary tumors (83% of the 204 children had secondary tumors spread from cancers elsewhere in the body). Pleuropulmonary blastoma is regarded as malignant. The male:female ratio is approximately one.

Malignant germ cell tumors of the mediastinum are uncommon, representing only 3 to 10% of tumors originating in the mediastinum. They are much less common than germ cell tumors arising in the testes, and account for only 1 to 5% of all germ cell neoplasms.

Syndromes associated with mediastinal germ cell tumors include Hematologic Neoplasia and Klinefelter's syndrome.

It was previously a relatively common complication of the massive lymphedema of the arm which followed removal of axillary (arm pit) lymph nodes and lymphatic channels as part of the classical Halstedian radical mastectomy, as a treatment for breast cancer. The classical radical mastectomy was abandoned in most areas of the world in the late 1960s to early 1970s, being replaced by the much more conservative modified radical mastectomy and, more recently, by segmental breast tissue excision and radiation therapy. Because of this change in clinical practice lymphedema is now a rarity following breast cancer treatment—and post-mastectomy lymphangiosarcoma is now vanishingly rare. When it occurs following mastectomy it is known as Stewart-Treves syndrome (which can be both lymphangiosarcoma and hemangiosarcoma following mastectomy). The pathogenesis of lymphangiosarcoma has not been resolved, however several vague mechanisms have been proposed. Stewart and Treves, proposed that a cancer causing agent is present in lymphedematous limbs. Schreiber "et al." proposed that local immunodeficiency as a result of lymphedema results in a "immunologically privileged site" in which the sarcoma is able to develop.

Squamous cell carcinoma (SCC) of the lung is more common in men than in women. It is closely correlated with a history of tobacco smoking, more so than most other types of lung cancer. According to the Nurses' Health Study, the relative risk of SCC is approximately 5.5, both among those with a previous duration of smoking of 1 to 20 years, and those with 20 to 30 years, compared to never-smokers. The relative risk increases to approximately 16 with a previous smoking duration of 30 to 40 years, and approximately 22 with more than 40 years.

The mediastinum (from Medieval Latin "mediastinus", "midway") is the central compartment of the thoracic cavity surrounded by loose connective tissue, as an undelineated region that contains a group of structures within the thorax. The mediastinum contains the heart and its vessels, the esophagus, trachea, phrenic and cardiac nerves, the thoracic duct, thymus and lymph nodes of the central chest.

The most successful treatment for angiosarcoma is amputation of the affected limb if possible. Chemotherapy may be administered if there is metastatic disease. If there is no evidence of metastasis beyond the lymphedematous limb, adjuvant chemotherapy may be given anyway due to the possibility of micrometastatic disease. Evidence supporting the effectiveness of chemotherapy is, in many cases, unclear due to a wide variety of prognostic factors and small sample size. However, there is some evidence to suggest that drugs such as paclitaxel, doxorubicin, ifosfamide, and gemcitabine exhibit antitumor activity.

The median survival time of patients without treatment is four to six weeks. The best prognosis are seen from NM due to breast cancer with the median overall survival of no more than six months after diagnosis of NM. Death are generally due to progressive neurological dysfunction. Treatment is meant to stabilize neurological function and prolong survival. Neurological dysfunction usually cannot be fixed but progressive dysfunction can be halted and survival may be increased to four to six months.

Factors that lower survival:

Much of prognosis can be determined from the damage due to primary cancer. Negative hormone receptor status, poor performance status, more than 3 chemotherapy regimes, and high Cyfra 21-1 level at diagnosis, all indicates lower survival period of patients with NM. Cyfra 21-1 is a fragment of the cytokeratin 19 and may reflect the tumor burden within the CSF.

Roughly 10–35% of NSCLC patients will have drug sensitizing mutations of the "EGFR." The distribution of these mutations have been found to be race-dependent, with one study estimating that 10% of Caucasians but 50% of Asians will be found to have such tumor markers. A number of different EGFR mutations have been discovered, however certain aberrations will result in hyperactive forms of the protein. Patients with these mutations are more likely to have adenocarcinoma histology and be non-smokers or light smokers. These patients have been shown to be sensitized to certain medications which block the EGFR protein known as tyrosine kinase inhibitors specifically, erlotinib, gefitinib or afatinib.

Reliable identification of mutations in lung cancer needs careful consideration due to the variable sensitivity of diagnostic techniques

Mediastinal germ cell tumors are tumors that derive from germ cell rest remnants in the mediastinum. They most commonly occur in the gonad but occasionally elsewhere.

The main medical risk factors are having bladder cancer or having conditions that cause chronic inflammation in the urethra. People over the age of 60 and white women have the highest risks.

Most ganglioneuromas are noncancerous, thus expected outcome is usually good. However, a ganglioneuroma may become cancerous and spread to other areas, or it may regrow after removal.

If the tumor has been present for a long time and has pressed on the spinal cord or caused other symptoms, it may have caused irreversible damage that cannot be corrected with the surgical removal of the tumor. Compression of the spinal cord may result in paralysis, especially if the cause is not detected promptly.

There are no known risk factors for ganglioneuromas. However, the tumors may be associated with some genetic problems, such as neurofibromatosis type 1.

Seminoma (also known as "pure seminoma" or "classical seminoma") is a germ cell tumor of the testicle or, more rarely, the mediastinum or other extra-gonadal locations. It is a malignant neoplasm and is one of the most treatable and curable cancers, with a survival rate above 95% if discovered in early stages.

Testicular seminoma originates in the germinal epithelium of the seminiferous tubules. About half of germ cell tumors of the testicles are seminomas. Treatment usually requires removal of one testicle. However, fertility usually isn't affected. All other sexual functions will remain intact.

Thyroid cancers are thought to be related to a number of environmental and genetic predisposing factors, but significant uncertainty remains regarding their causes.

Environmental exposure to ionizing radiation from both natural background sources and artificial sources is suspected to play a significant role, and there are significant increased rates of thyroid cancer in those exposed to mantlefield radiation for lymphoma, and those exposed to iodine-131 following the Chernobyl, Fukushima, Kyshtym, and Windscale nuclear disasters. Thyroiditis and other thyroid diseases also predispose to thyroid cancer.

Genetic causes include multiple endocrine neoplasia type 2 which markedly increases rates, particularly of the rarer medullary form of the disease.