Cancer therapies

Cancer therapies:

The three therapeutic types:

• Surgery
• Chemotherapy
• Radiotherapy
• Targeted therapy
• Bisphosphonates
• Hormone therapy

In some cases all five types of treatments are combined.

1. Chemotherapy:
2. How does chemotherapy work?

Chemotherapy drugs are used to slow or block the growth of cancer cells to prevent them from multiplying or invading other parts of the body.

Chemo destroys healthy cells that can partially repair themselves.

2. Types of chemotherapy:
3. Combination chemotherapy:

Used in case of resistant cancer cell

2. Neoadjuvant chemotherapy:

Reducing the size of a tumor before further treatment

3. Adjuvant chemotherapy:

Destruction of cancer cells after other treatments

4. Ablative chemotherapy:

Preparation for bone marrow or stem cell transplant

5. Palliative chemotherapy:

Relief of symptoms caused by cancer

3. Duration of chemotherapy:

Each case is unique: 6 months to 3 years

4. Routes of administration:

• Oral
• Injectable

5. The different chemotherapy drugs:
6. Alkylating agents and related agents:

Which act on the nucleic acids of the cell.

• Mesna – Lomustine – Cisplatine

2. Anti metabolites:

They block or divert one or more DNA synthesis pathways.

• Methotrexate (MTX).
• Fluorouracil (5FU)

3.  Cytotoxic antibiotics: 

Products of microbial origin that inhibit cell division:

• Anthracyclines
• Blemycins
• Dactinomycin

4.  Tubulo-affin and related agents:

Poison of the mitotic spindle because they inhibit the polymerization of microtubules during mitosis

• Vincristine

2.  Radiotherapy:
3. Definition:

Radiotherapy is the treatment for all cancers of the body (head and neck/oral cavity).

It is a locoregional treatment using radiation or IONIZING RADIATION to destroy cancerous tissue.

The main target of the rays is the DNA contained in the nucleus of tumor cells:

• Destruction of chromosomal structures responsible for cell division by modifying the electrical balance of molecular atoms, thus leading to the destruction of tumor cells.
• Ionizing radiation is a stream of moving particles capable of creating ions in the tissues they pass through.

2. How does radiotherapy work?

By a modification of the structure of the DNA: The cell can no longer divide, it dies. As a result, only the cells that divide are radiosensitive, neurons, red blood cells, leukocytes are radioresistant.

By double DNA breaks: occurring on both strands of the DNA molecule, responsible for cell death by necrosis.

3. Types of radiation: Different radiations:

• Co 60; electrons
• Photons
• Lons

4. Irradiation modalities: Different 
5. Conformational RT:

Radiotherapy technique which allows the irradiated volume to be adapted (conformed) as precisely as possible to the volume to be treated

When preparing for treatment, a scanner coupled with specific computer software allows the area to be treated to be viewed in three dimensions in a precise manner.

The aim of conformal radiotherapy is to limit as much as possible the dose of rays delivered to healthy tissues surrounding the tumor.

2. IMRT  :

Intensity-modulated radiotherapy: Radiotherapy that generates rays of irregular intensity by irradiating several small fields from as many different directions as possible.

• This intensity modulated radiation allows a dose distribution as conformal as possible within the framework of a three-dimensional superposition
• In addition to increasing the dose in areas particularly prone to recurrence. 
• At the same time, IMRT allows for better sparing of healthy tissues surrounding the tumor.
• Overall, IMRT offers greater efficacy against the tumor and a concomitant reduction in adverse event rates.
• This technique is particularly used for radiotherapy of head and neck tumors and prostate cancers.

5. Doses of radioactivity: 

The administered dose is the amount of energy delivered to tissues by radiation.

This energy causes phenomena that result in cell death.

The dose is measured and calculated using detectors or dosimeters

The usual protocol delivers a dose of 10gy/week at the rate of 5 sessions of 2 gy/day

The total dose, depending on clinical circumstances, varies from 30 to 70 gy

6. The dose unit:

The unit of dose is the gray (gy) which has supplanted 

The rad used to use.

1 gy represents an energy of 1 joule (1) absorbed in 1 kg of matter.

1 gy = 1 joule/1 kg of matter.

7. Different types of radiotherapy:
8. Curative radiotherapy:

To slow down, at the cost of a short and non-aggressive treatment, the evolution of the process by ensuring the patient a clinical remission as long as possible and above all without major disorder

To permanently sterilize all tumor cells contained in the irradiated volume in order to obtain local control and if possible cure.

2. Exclusive radiotherapy:

This type of treatment is indicated in 2 main circumstances:

As a palliative measure, in the event of metastasis or advanced cancer

3. Symptomatic radiotherapy:

The goal is to relieve a symptom, such as pain at an advanced stage of the disease but sometimes at an earlier phase.

4. Radiotherapy and surgery associations:

• Postoperative or adjuvant radiotherapy to reduce the risk of local relapse
• Preoperative or neoadjuvant radiotherapy performed 4 to 6 weeks before the operation.
• Intraoperative radiotherapy: directly targeted open-air irradiation, avoiding organs at risk as much as possible.

5. Radio-chemotherapy association:

Indicated in the treatment of tumors with high potential for dissemination and chemo-sensitive tumors. 

Chemotherapy provides targeted support to the largest tumor masses.

8. The main techniques: 3 main radiotherapy techniques:
9. External radiotherapy: 

Using a source of rays located outside the patient, at a certain distance from him. This could be a cobalt bomb or a particle accelerator

2. Curietherapy or brachytherapy:

Uses sealed radioactive sources containing iridium or cesium, placed in tumor tissue or in a natural cavity for intervention

3. Metabolic radiotherapy: 

Use of radioactive sources, injectable, unsealed, which will attach themselves, thanks to their metabolism, to the target cells:

• Iodine 131 (thyroid cancers)
• Phosphorus 32 (Vaquez’s disease)
• Strontium 89 and Samarium 153 (bone metastases).

4. Proton therapy and neutron therapy: 

They are little practiced

9. Most commonly used radiotherapy currently:

Modern brachytherapy is carried out using artificial radioelements such as Cesium 137 and especially Iridium 192.

These artificial radioelements have enabled the development of non-radioactive preparation techniques and have simplified the conditions of radiation protection.

Gamma rays are emitted by sealed radioactive sources introduced into the body: within the tumor in order to destroy the tumor cells there

1. Interstitial brachytherapy (or endo-brachytherapy):

Where the needles are placed in the tissues themselves. Tumors of the ENT sphere are treated by iridium wires introduced inside fine plastic tubes or hollow metal needles previously placed under local or general anesthesia within the tumor…

2. Endocavitary brachytherapy:

Tubes placed in natural cavities. 

Modality used in gynecology

3. Permanent implants:

Radar capsules left in tissues

10. Effects of radiotherapy on mature bone tissue:

Major risk: osteoradionecrosis

3. Surgery: 
4. Main objectives of surgical treatment:

It most often consisted of a wide tumor excision, removing the peritumoral cellulolymphatic and venous atmosphere.

2. Radical surgery:

It is defined by the excision of the entire tumor with a sufficient safety margin and of the entire cellulolymphatic and venous atmosphere that could be invaded by regional metastases of the tumor.

3. Cytoreductive surgery:

This is a non-radical surgery whose aim is to reduce the tumor volume as much as possible , in order to allow optimal action of chemotherapy for highly chemo-sensitive tumors.

4. Surgery for metastases.
5. Emergency palliative surgery:

It is surgery of necessity and/or comfort in an incurable patient.

6. Plastic and reconstructive surgery: It aims to:

• Either to restore the aesthetic appearance of the silhouette after mutilation made necessary by tumor excision .
• Either to restore a function after surgical mutilation (chewing and swallowing)
• Either to repair a loss of musculocutaneous substance caused by the wide excision of a tumor.

Cancer therapies

Untreated cavities can damage the pulp.
Orthodontics aligns teeth and jaws.
Implants replace missing teeth permanently.
Dental floss removes debris between teeth.
A visit to the dentist every 6 months is recommended.
Fixed bridges replace one or more missing teeth.