What is Lung Carcinoma (Lung cancer)?

Introduction

lung cancer is a leading cause of cancer-related deaths and it has a poor prognosis . In this article we will focus on lung carcinomas . So let us look at the different types of lung carcinomas and it can be divided into two broad types , small cell carcinoma and non small  cell carcinoma .Let us focus on small cell carcinoma.

Small Cell Carcinoma:

Small cell carcinoma represents about 15% of arm of these type of lung carcinomas more than 60% actually present already with metastases.  The prognosis of small lung, small cell lung carcinoma is poor. 

The tumor tends to grow approximately close to the hilum and involves neuro endocrine cells in the area . Because neuro endocrine cells are involved in this type of cancer they undergo mutations which allow them to produce hormone-like substances that they should not be able to produce .

Paraneoplastic Syndrome: 

And so as a result they release these hormones and it triggers a phenomenon known as the paraneoplastic syndrome , which we'll talk about later on . Non small cell carcinomas represents the majority of lung carcinomas 85%. 

Types of Non Small Cell Carcinoma

Non small cell carcinoma is further divided into three types.  

1. Adenocarcinoma:

Adenocarcinoma is the most familiar type of a non small cell carcinoma . Adenocarcinomas make up 38% of lung carcinomas . These types of cancers tend to occur in the peripheral lung tissue so away from the hilum and involves glands within the lung .

2. Squamous Cell Carcinoma :

Squamous cell carcinoma is the other type of non small cell carcinoma and makes up about 20% of lung carcinoma cases making it the second most prevalent type of lung carcinoma. These types of cancer tend to occur close to the main bronchus and can cause obstruction of the Airways . 

Why called Squamous cell carcinoma :

They are called squamous because the epithelia cells that line the airway become mutated and change from columnar cuboidal to squamous and essentially displays your cancer.

3. Large Cell Carcinoma :

The last type of non small cell carcinoma is large cell carcinoma which make up about 5% of lung carcinomas . So it is the least common large cell carcinoma rapidly grows like the small cell carcinoma and can present in the periphery or the peripheral lung tissue or the proximal lung tissue .

So those were the different types of lung carcinomas.

Let us look at the signs and symptoms of patients that present with lung carcinomas. Now not everyone presents like with these with the same signs and symptoms but the most common signs and symptoms include cough ,weight loss ,hemoptysis dyspnea and chest pain .

Risk Factors:

There are many risk factors for lung cancer major ones are smoking,  radon air pollution ,arsenic tar ,asbestos nickel . As well as there's family and genetic factors . 

Mediastinal Involvement of  Lung Cancer:

Now with cancer because it is a growth it can cause some problems to surrounding tissues ,surrounding organs. So let us look at some mediastinal involvement of  lung cancer . So let us zoom into the  media sternum  which where we can find the heart ,the lungs and all these other structures including the ribs .

Anatomy

Let us zoom into this first rib area and learn a bit and add a bit of anatomy . So here is a sternum and the first rib . Now going over the first rib are some important structures including the subclavian artery and vein and the brachial plexus , the nerves that innervate the upper limb.  

Why are we talking about these structures?

Why are we talking about these structures ? Because these structures have to do with the  pathophysiology or the complications associated with lung carcinomas. Lung cancers see the mediastinal involvement of lung cancer include Pancoast tumor growth which is growth on the apical lung surface .

Horner's Syndrome:

Pleural Effusion:

Another mediastinal involvement is pleural effusion which causes this Nia as well as chest pain.  There can also be heart involvement causing a pericardial effusion.

Superior Vena Cava:

Another important structure that can be affected is the superior vena cava which when blocked can cause the vena cava syndrome forget about the inferior vena cava.  That so it's superior vena cava so those were the  some mediastinal involvement associated with cancer lung cancer growth.

Airway Involvement:

Let us look at the airway involvement.  Now so the Airways of the lungs or the bronchi and the bronchioles right before it terminates at the alveoli . Well cancer can cause airway obstruction as it impedes air flow airway obstruction leads to dis Nia . 

When there is airway obstruction or irritation this actually sends sensory information to the brain and triggers the coffee flecks that is why in presentation we have dis Nia and cough the patients have dis Dion cough cancer or tumor .

Angiogenesis:

It also stimulates angiogenesis which is blood vessel growth . However angiogenesis forms leaky and tortuous vessels which when ruptures and  can lead to what leads to hemoptysis.

Involvement of Blood Vessel:

Let us zoom into the blood vessels . The blood vessels contain your red blood cells platelets and white blood cells right in lung cancer we see some blood involvement mainly anemia which leads to fatigue and dis Nia leukocytosis and 15% of cases thrombocytosis in 15% of cases and hypercoagulable disorders. 

Metastasizes:

Lung tumors can metastasize and they do when it metastasizes it goes to the heart and then the heart will pump the tumor the the growth the cancer either up to the brain and upper limbs or down to the abdomen area .

Common sites of lung metastasis include the brain, the liver ,the adrenal glands and the bone metastases sites are commonly asymptomatic . 

Paraneoplastic Syndrome:

Now looking back to the different types of lung cancer remember the neuro endocrine cells that begins to creating hormones in the small cell carcinoma well it leads to the phenomenon called paraneoplastic syndrome . Let us learn a bit more about what this encompasses.

Harmones associated with syndromes:

So the paraneoplastic syndrome typically occurs in small cell lung cancer . As well as squamous cell carcinomas paraneoplastic syndrome are syndromes that occur not related to invasion obstruction or metastasis of primary tumor and they and the paraneoplastic syndrome include the following ectopic Cushing's syndrome where the hormone released by cancer cells stimulate the adrenal glands to produce cortisol .

Antidiuretics:

We also have antidiuretic like substance which stimulates up secreted by the new endocrine cells which stimulate the kidneys to retain water . These neuro endocrine cells also produce a parathyroid hormone like substance which stimulates the bone to break down.  

Its minerals and release calcium into plasma increasing blood calcium levels resulting in hypercalcemia .

Hyper Pulmonary  Osteopathy and Myopathy:

Paraneoplastic syndrome also include are the hyper pulmonary  Osteopathy leading to clubbing and periosteal proliferation of the tubular bone and lastly inflammatory myopathies can result from lung cancer which leads to the muscle weakness and so that is why we see signs of finger weakness on upon examination of patients with lung cancer okay so that was essentially the pathophysiology .

Investigations

Let us look at some investigations we would do if we were suspicious of lung cancer . So lung involvement we always do a chest x-ray to rule out other differentials common clinical findings on x-ray for lung cancer include a high lemon largeman pulmonary opacity which represents the tumor . 

CT Scan :

Three rib bone lesions , pleural effusion and also lung collapse. Another investigation which is critical for  this is seat for lung cancer is CT scan and should be performed early to determine stage and management of the cancer .

Not only CT scans but biopsy are to be performed which include the bronchoscopy which is where the primary lung tumor is visualized and sample is taken using the instrument . 

 CT Guided Find Needle Biopsy:

You can also perform a CT guided find needle biopsy which is a more reliable way to obtain a histological diagnosis . A needle aspiration this is where a needle is inserted in the lump of the lung or lymph node to see for lymph node involvement .

Another form of Investigation for biopsy is the authorial Kosan tesis which is where fluid is collected from the pleural cavity and this is used for sampling again our numbers three, four, five and six are used for biopsy to stage the tumor .

Clinical Management

So that appropriate management can be taken and so management is the next topic we'll talk about. 

Surgical Treatment:

So these are one surgical treatment which is the most important surgical treatment is for the removal of  the tumor of the lung tumor cancer for stages one and  the stages two after surgery or if  the surgery cannot be performed.

Radiotherapy and Chemotherapy:

There is also radiotherapy and chemotherapy as well as laser therapy and stenting radiotherapy is less effect is less effective than surgery however radiotherapy is used in combination with chemotherapy for stages three chemotherapy increases survival up to two one year.

Side Effects:

Nausea and vomiting are side effects , these side effects are managed best by the 5-htt 3 receptor antagonists because these drugs will target the chemoreceptor trigger zone thus preventing the vomiting nausea associated symptom .

Laser Therapy and Stenting:

Laser therapy and stenting can also be done airway obstruction from the tumor growth causing serious symptoms can be managed using laser treatment and stenting so essentially the obstruction of the airway you basically remove it so airflow can can return as normal.