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Cancer and The Environment


Cancer and The Environment overview and Definition

Cancer is a disease in which some of the body’s cells grow uncontrollably and spread to other parts of the body. 


Pathophysiology

The following genes take part in the cancer:

  • Oncogenes – these are cancer causing genes. They may be normal genes which are expressed at inappropriately high levels in patients with cancers or they may be altered or changed normal genes due to mutation. In both cases these genes lead to cancerous changes in the tissues.
  • Tumor suppressor genes – these genes normally inhibit cell division and prevent survival of cells that have damaged DNA. In patients with cancer these tumor suppressor genes are often disabled. This is caused by cancer-promoting genetic changes. Typically, changes in many genes are required to transform a normal cell into a cancer cell.

Genomic amplification

Sometimes there may be genomic amplification. Here a cell gains many copies (often 20 or more) of a small chromosomal locus, usually containing one or more oncogenes and adjacent genetic material.

Point mutations

Point mutations occur at single nucleotides. There may be deletions, and insertions especially at the promoter region of the gene. This changes the protein coded for by the particular gene. Disruption of a single gene may also result from integration of genomic material from a DNA virus or retrovirus. This may lead to formation of Oncogenes.

Translocation

Translocation is yet another process when two separate chromosomal regions become abnormally fused, often at a characteristic location. A common example is Philadelphia chromosome, or translocation of chromosomes 9 and 22, which occurs in chronic myelogenous leukaemia, and results in production of the BCR-abl fusion protein, an oncogenic tyrosine kinase.

Tumors

A tumor in latin means a swelling but not all swellings are tumors in the modern sense of the term. Some of them may be caused due to inflammation, infections, cysts or fluid filled lesions or due to benign growths. A cancerous tumor has the capacity to grow rapidly and to metastasize or spread to other tissues. Some tumors like leukemias grow as cell suspensions but most grow as solid masses of tissue.

Solid tumor parts

Solid tumors have two distinct parts. One of them is the parenchyma that contains cancer tissues and cells and the other is the stroma that the neoplastic cells induce and in which they are dispersed.

 

Structure of cells:

  • Hyperplasia occurs when cells within a tissue multiply faster than normal and extra cells build up. However, the cells and the way the tissue is organized still look normal under a microscope. Hyperplasia can be caused by several factors or conditions, including chronic irritation.
  • Dysplasia is a more advanced condition than hyperplasia. In dysplasia, there is also a buildup of extra cells. But the cells look abnormal and there are changes in how the tissue is organized. In general, the more abnormal the cells and tissue look, the greater the chance that cancer will form. Some types of dysplasia may need to be monitored or treated, but others do not. An example of dysplasia is an abnormal mole (called a dysplastic naevus) that forms on the skin. A dysplastic nevus can turn into melanoma, although most do not.
  • Carcinoma in situ is an even more advanced condition. Although it is sometimes called stage 0 cancer, it is not cancer because the abnormal cells do not invade nearby tissue the way that cancer cells do. But because some carcinomas in situ may become cancer, they are usually treated.

 


Clinical signs & symptoms

Loss of apetite

Constipation

Vomiting

Severe weight loss

Pain in and around the organs involved

Insomnia

Loss of taste

Aggressiveness

Depression

Hair loss

 


Differential Diagnosis

Colposcopy: This is visual examination of the vagina using a speculum and a colposcope, a lighted                magnifying instrument.

  • Examination under anesthesia (EUA): The doctor can examine the organs more thoroughly.
  • Biopsy: The doctor takes a small section of tissue under general anesthesia.
  • Cone biopsy: The doctor takes a small, cone-shaped section of abnormal tissue from the organ for examination.
  • LLETZ: Diathermy using a wire loop with an electric current helps remove abnormal tissue. The healthcare professional then sends the tissue to the lab for checking.
  • Blood tests: A blood cell count can help identify organ problems.
  • CT scan: A medical professional might use a barium liquid to show up any cellular abnormalities.
  • MRI: Special types of MRI may be able to identify the organ cancer in its early stages.

Ultrasound: High-frequency sound waves create an image of the target area on a monitor.

  • Stages:
  • Stage 0:
  • The cancer is not spread but has potential development of the cancer in the future which is termed as carcinoma insitu.
  • Stage 1:
  • The cancer cells are consider to the localized area. This is also called the early stage cancer
  • Stage 2 and Stage 3:
  • It indicates that the cancer cell has spread to the nearby lymphnodes or tissues.
  • Type 4 :
  • It indicates that the cancer has spread to other parts of the body and also it easily gets metastasis. This is also called an advanced type of cancer.

 

 

 Another common staging tool is the TNM system, which stands for Tumor, Node, Metastasis. When a patient’s cancer is staged with TNM, a number will follow each letter. This number signifies the extent of the disease in each category. According to the National Cancer Institute and MD Anderson experts, the standard TNM system uses the following rules:

Primary tumor (T)

  • TX: Main tumor cannot be measured.
  • T0: Main tumor cannot be found.
  • T(is), or T in situ: The tumor is still within the confines of the normal glands and cannot metastasize.
  • T1, T2, T3, T4: Refers to the size and/or extent of the main tumor. The higher the number after the T, the larger the tumor or the more it has grown into nearby tissues. T's may be further divided to provide more detail, such as T3a and T3b.

Regional lymph nodes (N)

Lymphatic fluid transports immune system cells throughout the body. Lymph nodes are small bean-shaped structures that help move this fluid. Cancer often first spreads to and through nearby lymph nodes.

  • NX: Cancer in nearby lymph nodes cannot be measured.
  • N0: There is no cancer in nearby lymph nodes.
  • N1, N2, N3: Refers to the number and location of lymph nodes that contain cancer. The higher the number after the N, the more lymph nodes that contain cancer.

Distant metastasis (M)

Metastasis is the spread of cancer to other parts of the body.

  • MX: Metastasis cannot be measured.
  • M0: Cancer has not spread to other parts of the body.
  • M1: Cancer has spread to other parts of the body.


Prognosis

The prognosis mainly depends upon the stage it involves. The first two stages have good prognosis. The patient with fourth stage tends to have metastasis wherein the cancer spreads to other organs and increases the fatality rate of an individual.


Prevention

Follow healthy diet

Screening is must for the people who have crossed 40 years of age

Avoid smoking and consumption of alcohol

Reduces the stress

Reduce the weight

Intake large amount of fiber containing foods

Be physically active