Lung Carcinoid Tumors – Types, Symptoms, Causes, Risks, Diagnosis, Stages and Treatment

Lung Carcinoid Tumors – Types, Symptoms, Causes, Risks, Diagnosis, Stages, and Treatment: Carcinoid tumors are a very rare presentation of lung cancer. It is also known as the pulmonary neuroendocrine tumor (NET) and comprises only one to two percent of lung cancer. It grows slowly. It is named so because it starts to grow in certain specialized cells known as neuroendocrine cells. These cells are found in the whole body. It usually produces no symptoms in its early stages and is identified during the examination for any other disease or during any surgery.

If symptoms appear, they may be tiredness, nausea, or pain and signs such as Fever, skin rash, or high heart rate. Together, the signs and symptoms can help describe a medical problem. It also describes the signs and symptoms of carcinoid syndrome and carcinoid crisis, which are conditions that can cause pulmonary NETs. If you experience any such signs and symptoms then you should consult your doctor.

Lung Carcinoid

Neuroendocrine cells are found in the whole body. The lung carcinoid is made of these neuroendocrine cells only. These cells are called so, as they are like endocrine cells and secrete hormone-like substances. On the other hand, they are also like nerve cells as can secrete neurotransmitters. In unusual circumstances, these nerve cells’ growth rate increases and results in the formation of tumors. Such tumors can form in the whole body and fact says lung carcinoids are only accountable for about 2% of cancers among the whole-body cancer of the same category. 

Cancer Symptoms

Chemotherapy Side Effects

Types of Lung Carcinoid

1. Typical Lung Carcinoids – 90% of lung carcinoid are of typical type and is found in the central airway of the lungs. Their growth rate as compared to other lung tumors are slow and rarely extends beyond the lungs. It resembles malignant lung cancer with signs and symptoms such as severe cough and hemoptysis. Another way to categorize lung NET is through their location, the ones which are present on the outer edge are termed as peripheral carcinoids. And the one which are present in the center of the airways is termed as central carcinoids. About 80-90 % of patients get to live for another 5 years with this carcinoid.
2. Atypical Lung Carcinoids – they are rare than typical carcinoids and can metastasize beyond the lungs. They also tend to grow faster than typical carcinoids. These tumors have increased cell divisional and death (necrosis) activity. About 50-70% of patients get to live for another 5 years with this cancer.

Causes of Lung Carcinoids

The exact cause of the formation of lung carcinoids before any other lung cancer is not very certain, however, certain factors that increase the risk may include-

1. Gender – women are more prone to get lung carcinoids than men.
2. Skin color – there are more common in white race people than in any other people of different races.
3. Genetic- people with a family history or who inherited the gene for MEN-1 (Multiple Endocrine Neoplasia type-1) are at more risk of developing lung carcinoids than others. The presence of this syndrome acts as a precursor for other carcinoids such as pancreatic, pituitary, etc. 
4. Family history – if you have a family history of any carcinoid, then you are more at risk of getting caught.

Lung Carcinoids Symptoms

Usually, there are no specific symptoms of lung carcinoid and is usually identified while diagnosing other complaints from patients or during chest examination via imaging, scanning, etc.  Symptoms generally include-

1. Cough and wheezing – it may contain sputum and sometimes sputum along with blood. In severe cases.
2. Infections – when the tumor grows big enough to block the air passage then it causes post-obstructive pneumonia.
3. Carcinoid syndrome – it happens very rarely, but in this, the tumor neuroendocrine cells start overproduction of certain hormones.
4. Facial flushing – it usually mimics blushing and is the redning of the face. But in this, the person feels the warmth on the face, a burning hot sensation which is due to the overproduction of serotonin. In this condition, the serotonin is overproduced and released into the systemic circulation.
5. Hirsutism – an overgrowth of facial hairs and body hairs.
6. Others include weakness, chest pain, weight gain, high blood pressure, etc.

Diagnosis for Lung Carcinoids

If you feel any of the above symptoms, you should visit a pulmonologist or a general physician. They will ask you about your family history and physically examine your lungs in the beginning. After this, a set of tests will be done to look for the matter in detail. This might include-

• Blood test – to look for the presence of any abnormal or elevated hormone or substance, a blood test, and urine test will be done. It is done to look for the presence of serotonin and chromogranin A. the presence of this compound will indicate the carcinoid tumor.
• Urine test – it is done to look for the 5-HIAA, serotonin metabolite. Both tests will produce reproducible results for people who have carcinoid syndrome and lung carcinoid. But for people with no symptoms, these tests will do just fine.
• X-ray – an x-ray will detect the presence of any tumor in the lung, except if the tumor is too short or is covered by any other organ.
• CT-Scan – it is a 3-D imaging technique. In case an X-Ray does not clear the situation, it can be done to even find the smallest tumor and the exact location of the tumor. It even can state the spreading status of the tumor.
• Biopsy – it is a process in which a minute portion of the tumor is removed and examined under the microscope. It is of two types:
• Surgical – it is like an operation procedure, in which under the effect of anesthesia, a cavity is made in the chest and then the tumor sample is taken. This requires proper recovery time and hospitalization.
• Non-surgical – this is done in normal hospitals or clinics. In this under the effect of a normal sedative, a sample is taken without a surgical incision. The best example of this is bronchoscopy, in this, a thin wire is inserted in your chest through a windpipe and a biopsy is done under direct vision.

Lung Carcinoids Stages

The stages of lung carcinoid are identified on the basis of the size of the tumor (T), its spread to the surrounding lymph node (N), and metastasis (M). It is classified into four stages. Stage zero is the smallest tumor and stage fourth is the tumor biggest in size. Further staging of lung carcinoid tumor according to the AJCC (American Joint Committee on Cancer) is given below in the table-

S.NO.	AJCC Staging	Stage Group	Description
1	occult cancer	TX	the cancer is found somewhere in the body but cannot be located.
		NO	cancer has not spread to the surrounding lymph node
		MO	cancer has not spread to any other body part
2	0	Tis	the cancer cells are found superficially on the air passage and have not invaded deeper
		NO	cancer has not spread to the surrounding lymph node
		MO	cancer has not spread to any other body part
3	IA1	T1a	The tumor has not reached the main branches of the bronchi and the membrane of the lungs and is no larger than 1 cm in size.
		NO	cancer has not spread to the surrounding lymph node
		MO	cancer has not spread to any other body part
4	IA2	T1b	The tumor has not reached the main branches of the bronchi and the membrane of the lungs and is approx. 1-2 cm in size.
		NO	cancer has not spread to the surrounding lymph node
		MO	cancer has not spread to any other body part
5	IA3	T1c	The tumor has not reached the main branches of the bronchi and the membrane of the lungs and is approx. 2-3 cm in size.
		NO	cancer has not spread to the surrounding lymph node
		MO	cancer has not spread to any other body part
6	IB	T2a	1) the cancer is 3-4 cm in size 2) tumor has grown into the main branches of the bronchi, and visceral pleura and partially clogging the air passage,  but has not reached into the carina
		NO	cancer has not spread to the surrounding lymph node
		MO	cancer has not spread to any other body part
7	IIA	T2b	1) The cancer is 4-5 cm in size 2) tumor has grown into the main branches of the bronchi, and visceral pleura and partially clogs the air passage, and has also reached the carina.
		NO	cancer has not spread to the surrounding lymph node
		MO	cancer has not spread to any other body part
8	IIB	T	T1a/T1b/T1c or T1a/T2b  or T3
		T3	The tumor is 5-7 cm in size and it has now invaded the parietal pleura, and parietal pericardium there is more than one tumor in the lung.
		NO	NO or N1
		N1	cancer has spread to the hilar lymph node and lymph node and is on the same side
		MO	cancer has not spread to any other body part
9	III A	T	T1a/T1b/T1c or T1a/T2b  or T3 or T4
		T3	The tumor is 5-7 cm in size and it has now invaded the parietal pleura, and parietal pericardium there is more than one tumor in the lung.
		T4	The tumor is larger than 7 cm and has spread to the heart, blood vessels, windpipe, stomach, esophagus, and spine. There are more than two tumors at different locations in the lung.
		N	N2 or N3
		N2	The tumor has spread into the carina and the space between the lungs. The lymph node and tumor are on the same side
		N3	Cancer has spread to the collarbone on either side of the body.
		Mo	cancer has not spread to any other body part
10	III B		T1a/T1b/T1c, N3,MO
			T2a/T2b, N3, MO
			T3,N2.MO
			T4,N2,MO
11	III C		T3,N3,MO
			T4,N3,MO
12	IV A	T	any T
		N	any N
		MO	M1a/ M1b
		M1a	cancer has spread in both the lungs
		M1b	The single tumor has spread outside the lungs into the bone, liver, or brain.
13	IV B	T	any T
		N	any N
		M1c	more than one tumor has spread outside the chest into the other organs

Treatment for Lung Carcinoids

Treatment is given to a patient on the grounds of the diagnosis which reveals the type of tumor (typical or atypical/peripheral or central), whether its spread is limited to the lungs or affected any other organ and the stage of the tumor. The stage of the tumor is decided by the size of the tumor. The AJCC categorizes the tumor into stages from a minimum as stage-0 to a maximum as a stage- IV.

The treatment involves surgical and radiation procedures. However, most lung carcinoids are moved by surgery alone but if the tumor has spread to other organs, then a palliative tumor is removed through surgery to relieve the symptoms. And then radiation therapy is given to remove it completely from the body.

Surgical treatment –

Lobectomy – it is the removal of one love from the lung. The removal of both lobes is known as bilobectomy. It is done in the case of the peripheral tumor. For example, sleeve resection, in this, the tumor is removed along the airway portion above and below it and then the airway is stitched back.

Sulobar resection – it includes segmentectomy, in which the segment of the lobe of the lung is removed. It also includes wedge resection, in which a small portion in the shape of a wedge is removed from the lung.

Pneumonectomy – In this procedure, the entire lung is removed as the tumor is spread to the entire lung.

Dissection of lymph node – during removing a tumor, often lymph nodes are removed to see the spread of the tumor in it. It is also done to prevent the spread of tumors to other organs.

Radiation treatment – it requires more than one session. High-intensity radiation exposure is done to destroy cancer cells. It is the general therapy given to destroy cancer cells.  Mall pellets and rods are sent to a tumor through a catheter and then a radiation beam is given to them so that the tumor can be destroyed. This procedure is known as brachytherapy.

Chemotherapy – this is the supply of drugs intravenously into the veins to destroy the cancer cells. Certain drugs used in this technique are given as pills, through injections, shots, creams, etc. this therapy can be given in a doctor’s clinic or in a hospital. However, there are several side effects of this treatment which can be managed in many cases.

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