GENERAL NOTIONS ON CANCEROLOGY
Plan:
INTRODUCTION
- GENERALITIES
- DEFINITION
- CHARACTERISTICS OF BENIGN AND MALIGNANT TUMORS
- FORMATION OF CANCER CELLS
- RISK FACTORS
- CARCINOGENESIS
- THE TNM CLASSIFICATION
- DIAGNOSIS OF CANCERS OF THE CERVICOFACIAL REGION
CONCLUSION
2023/2024
GENERAL NOTIONS ON CANCEROLOGY
Main objective
Identifying cancer
Secondary objectives
- Define cancer
- Distinguishing between a benign tumor and a malignant tumor (cancer)
- List and recognize the clinical signs of malignancy
- List the histological signs of malignancy
- Identify risk factors for cancer
- Define the different stages of carcinogenesis
INTRODUCTION :
Cancerology, oncology or carcinology is a medical specialty which allows the study, diagnosis and treatment of cancers (Kc).
It is a rapidly progressing disease that affects all parts of the body.
At the level of the oral mucosa, squamous cell carcinoma: the most frequent.
1-GENERAL INFORMATION
Cancer refers to a malignant tumor. The word “tumor” is not specific to cancer. The term tumor comes from the Latin word “tumor” which means swelling.
Tumor is synonymous with neoplasm or neoplasia which is a generic name that designates a pathological tissue neoformation different from an inflammation. The tumor can be “benign” or “malignant”. Benign tumor also called benign neoplasm. Malignant tumor also called malignant neoplasm or cancer.
2-DEFINITION
Cancer comes from the Latin word for crab because the cancerous cell extensions that invade healthy tissues resemble crab claws. Kc is the result of an uncontrolled proliferation of “malignant” cells because they have acquired certain abnormal characteristics.
Malignant Tumor: is an anarchic proliferation of abnormal cells. Rapid growth, poorly limited, invades neighboring tissues. It presents ADPs, altered general condition, gives metastases. The Tumor presents the possibility of recurrence after treatment.
Depending on the tissue of origin, we distinguish: malignant tumors of epithelial origin (carcinoma) and tumors of connective tissue origin (sarcoma).
– Metastases: linked to the ability of cancer cells to detach from the primary tumor and migrate to a distance, creating independent tumor foci. The main locations: regional lymph nodes (primary metastases), then the lungs, liver, bones and marrow.
3- CHARACTERISTICS OF BENIGN AND MALIGNANT TUMORS:
| Benign tumors: | Malignant tumors: |
| They develop locally and remain confined to the tissue in which they originated. Their growth is slow. However, they can reach a significant volume and weight. They do not recur after surgical removal, provided that the excision is complete. These tumors never metastasize. Their evolution is generally favorable. | Usually have rapid growth. They give rise to distant tumor dissemination (especially by lymphatic and blood route) with hatching and development of secondary tumors in other viscera called metastases. Malignant tumors tend to recur after local eradication. The evolution, in the absence of treatment, is spontaneous towards death. |
4- Formation of cancer cells:
4.1 The cancer cell:
The cancer cell has the following phenotypic characteristics
- Loss of contact inhibition
- Independence from growth factors
- Immortality
- Tumoregenicity
4.2 General characteristics of the cancer cell:
The cell retains a certain degree of differentiation characteristic of the original tissue
4.3 Acquired morphological characteristics:
- Nucleus abnormalities: large, multiple, visible nucleoli, hyperploidy
- Cell size abnormalities: heterogeneous
- Cytoplasmic abnormalities: increased cyto-nuclear ratio
- Cytoplasmic membrane abnormalities: loss of contact inhibition, altered adhesiveness, changes in surface antigens
4.4 Acquired dynamic characters:
- High, autonomous, anarchic and indefinite rate of mitoses
- Cell death due to hypoxia
5-RISK FACTORS
5.1- Tobacco is the direct cause or a contributing factor for many types of cancer. It is responsible for more than 8 out of 10 lung cancers, nearly 70% of cancers of the upper aerodigestive tract (mouth, larynx, pharynx, esophagus) and 50% of bladder cancers.
5.2- Alcohol is classified as carcinogenic to humans by the International Agency for Research on Cancer (IARC). The ethanol contained in alcoholic beverages is transformed in the body into compounds that promote the development of cancer.
Alcohol increases the risk of developing certain cancers such as: cancers of the oral cavity, larynx and pharynx; cancer of the esophagus…
5.3-Nutritional factors: Many studies have highlighted the influence of nutritional factors on the risk of developing cancer, even if there are still uncertainties about the exact role of some of them. Thus, a balanced and diversified diet, favoring fiber, fruits and vegetables, can reduce the risk of developing cancer.
5.4- Chronic lesions: Any untreated chronic lesion is a risk factor, especially if others are associated, namely: trauma, chronic candidiasis, lichen planus, etc.)
5.5- Viruses: Oncogenic viruses are viruses that have the capacity to make the cell they infect cancerous. Ex: -Papillomavirus (HPV 16 and HPV18), Epstein Barr, hepatitis B or C virus.
5.6- Ionizing radiation: Exposure to ultraviolet rays, whether natural (sun) or artificial (UV tanning booths), is the cause of the vast majority of skin and lip cancers, etc.
5.7 – Genetic predisposition:
Cancer develops because of the mutation of one or more genes.
5.8 – Age: With age, the increase in the number of cell divisions multiplies the risks of mutations and consequently the risk of cancers.
GENERAL NOTIONS ON CANCEROLOGY
6-CARCINOGENESIS
– Carcinogenesis: Cancer forms following anarchic cell division.
In the normal state, cell division is based on an identical replication of the two DNA chains. The balance between mitosis and apoptosis gives the normality of a tissue or an organ, this is controlled by genes. The P53 protein controls this balance, it is an anti-oncogene (inhibits the division of abnormal mutated cells). Pro-oncogenes stimulate cell division.
Any disruption of this balance causes cancer.
Carcinogenesis occurs through:
- Initiation: Which has no clinical translation, by which an irreversible lesion of the DNA is transmitted to daughter cells called initiated. The initiating agents can be of chemical, viral or physical nature.
- Promotion: Proliferation of altered and transformed cells within the epithelium.
- Progression: the ability of cells to cross walls and give rise to local tissue invasion and regional and visceral metastases.
7-THE TNM CLASSIFICATION
The TNM is a classification system based on local, regional (nodal) and metastatic tumor extension.
It was established to allow comparisons, particularly international ones. It was initially exclusively clinical in order to be applicable by all teams.
In a way, the TNM summarizes the observation but does not replace it. On its own, it cannot allow the indications to be posed correctly.
- The T ranges from 1 to 3 or 4 depending on the local extension revealed by the clinicoradiological assessment.
- The N ranges from NO to N3 depending on the size and location of the adenopathies.
- N- and N+ are used in the absence or presence of lymph node invasion during anatomopathological analysis of the lymph nodes.
The M corresponds to the existence {Ml} or not {MO} of metastases. For comparisons, the cases can be grouped into stages according to the following usual scheme:
- Stage 1: Tl NO MO
- Stage II: Tl Nl MO and T2 NO or Nl
- Stage Ill: Tl N2 T2 N2 T3 NO or Nl or N2
- Stage IV: T4 and/or N3 and/or M positive.
8. DIAGNOSIS OF CANCERS OF THE CERVICO-FACIAL REGION
8.1 – Interrogation
- Medical and surgical history, profession , assess general condition, weight loss and appetite loss
- Search for functional signs:
- discomfort or pain in function
- earache, dysphonia
- nasal obstruction, epistaxis, oral hemorrhage, tooth mobility
- presence of isolated mouth opening limitation, ADPs
- hypo or anesthesia in the mental nerve territory
- presence of a swelling or ulceration that does not heal
- Assessment of risk factors (alcohol and tobacco poisoning)
8.2 – Exo-oral examination
- Facial symmetry
- Examination of the integuments
- mouth opening
- facial innervation (motor and sensory)
- search for ADPs (seat, number, size, mobility). This examination is an essential part of the examination.
8.3 – Endo-oral examination
- assess oral hygiene
- examination of the mucous membranes: ulceration, nodule, bubbling, hemorrhage,
- palpation: consistency, presence or absence of induration, mobility in relation to deep planes
- dental examination: mobility
- sensitivity test.
GENERAL NOTIONS ON CANCEROLOGY
8.4 – Additional examinations
- Biological tests: FNS, VS, alkaline phosphatases, tumor biomarkers (P53)
- Radiological examinations
- The panoramic scan is limited to dental structures to assess the limits and extension of the tumor, specific incidences are required such as: CT, MRI to determine the invasion of soft parts, ADPs.
- The radiological signs of malignancy to be looked for are the presence of irregular osteolysis with imprecise limits or rupture of the cortical bones and infiltration of the soft tissues.
- Biopsy: this is the removal of part of the lesion for histological examination to confirm or rule out the clinical diagnosis and establish the therapeutic approach.
- Scintigraphy: To detect primary bone cancers. It uses Technitium 99.
- Extension assessment: Once the diagnosis has been made, it is necessary to assess the extension of the tumor, local or distant, and the search for associated lesions. It is based on a general lymph node assessment (CT scan, scintigraphy, pneumothorax).
CONCLUSION :
The general notions of cancerology are important to know given the magnitude of this disease. We have therefore answered the question of how and why cancer occurs. We can also answer that cancer progresses through different phases, two of which are decisive:
- The initiation which corresponds to the mutation of the cell;
- The promotion which corresponds to the anarchic multiplication of this cell and the appearance of the tumor.
Cancer was one of the many scourges of man and one that is not ready to be completely mastered.
GENERAL NOTIONS ON CANCEROLOGY
Bibliographic references:
- BENHAMOU E., FAU A., SCHLUMBERGR M.: TNM classification of malignant tumors 6th ed. France: Cassini, 2003; 261.
- Barouki R. (2014) Environment and health: the combination of exposures, Public health issues, 26, 1-4.
- Goodson III WH et al. (2015) Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead, Carcinogenesis, 36 (Suppl. 1), 254-296.
- D. Hanahan et al. Hallmarks of cancer: the next generation Cell (2011).
- YAFouad et al. Revisitig the hallmarks of cancer.Am J CancerRes(2017).
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Bruxism, or teeth grinding, can cause premature wear and often requires wearing a retainer at night.
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Pediatric dental care is essential to establish good hygiene habits from an early age.