W8 Anticancer strategies Flashcards
What are the 3 traditional approaches to the treatment of ca?
Surgery
Radiotherapy
Chemotherapy
What are the novel approaches/terms to ca treatment? (7)
- Immunotherapy
- Anti-hormonal therapy (chemotherapy)
- Targeted Chemotherapy (“Precision oncology”- chemotherapy)
- Biosimilars
- Epigenetic Therapy (chemotherapy)
- Hyperthermic Chemotherapy (chemotherapy)
- Photodynamic therapy
What are the Aims of cancer treatments? (3)
1-Curative: radical treatment to kill or remove all the cancer cells present
2-Control: stop cancer from progression to improve the length and quality of life
3-Palliation: reduce tumour load and improve symptoms (less aggressive approach)
A chemotherapeutic drug can be considered what..? (4)
1-Curative: radical treatment (high dose) to kill all the cancer cells present
2-Adjuvant: kill remaining cancer cells aftersurgery or radiation
3-Neoadjuvant: reduce tumour size before surgery or radiation
4-Palliative: treat but not aggressively to help symptom
What are the Clinical events in the treatment of cancer?
- Screen vulnerable populations for the pre-
malignant signs/early stages of some
cancers (IDEAL). Patient detects symptoms
and reports these to a doctor - If diagnosis is confirmed → state of development of the cancer (staging)
and the type of cancer is established
→ type of treatment - Kill residual cancer cells and possible metastases
* Regions of anatomical complexity or vital
biological functions (head, neck, brain,spine) surgery would cause many problems →radiotherapy
See canvas flow diagram!
1-Early detection means better results
Why is this?
- Cancer can be physically detected → has been developing for a long time 1cm tumour has passed through three-quarters of its lifespan
- More time= increased cellular change towards aggressiveness
- The earlier a cancer can be detected, the fewer changes it will have undergone and
the more likelihood there will be of getting a good response to treatment - Increased likelihood of achieving a cure when small numbers of cancer cells are present at the start of therapy
Early detection (for info)
Remission means how many cancer cells left in the body?
A cancer comprising 10^9 cells: only detectable by physical examination of patients
Relationship of Cell no to Pt status:
Detection: 10^8= 1cm3 most solid cancers reach cm3 before detection
Remission= 1mm3 means pt may still have 10^5 cells remaining!
Death= 10^12 cancer cells in body
- Graph shows that screening campaigns (if possible) are fundamental
37 trillion cells in our bodies
2-Potential response to treatment
What is Relapse-free/ overall survival time?
To “Measure” a response and the effectiveness of treatments → patients informed about
the likely outcome of their treatments
Response to the treatment (usually 6 months) can be classified as what?: (6)
- Cure: no evidence of disease for a minimum of 5 years
- Complete response: cancer disappears completely (relapses still possible)
- Partially response: disappears partially (tumour size reduced at list by 30%)
- Clinical benefit: level of improvement is not reached; patient has experienced significant attenuation of symptoms and/or enhancement of quality of life
- Stable disease: tumour size increased by < 20% or decreased by < 30%
- Progressive disease: continues to grow (20% or higher level )
3-Patient criteria: stage and grade
What is this based on?
How many stages are there?
- Based on tumour size and degree of spread (stage of disease)
TNM system: based on the three criteria of Tumour size (T1 to T4), spread to the lymph Nodes (N0 to N3) and Metastasis to distant sites (M0 or M1)
Stage 1 (localised): small size that has not progressed outside its original site
stage 2 (local) and 3 (regional): intermediate disease severity
Stage 4 (metastatic): growth is large and has spread widely
Size: bigger size limits drug and oxygen delivery to large tumours
3-Patient criteria: stage and grade
- Based on the cellular characteristics of the cancer (grade or histological grade)
What is a low grade vs high grade tumour?
What are the criteria for grading?
How histologically similar is the tumour to the tissue of origin?
Low-grade tumour: histological resemblance to the tissue of origin
High-grade tumour: undergone so many changes → resembles the tissue of origin only marginally
STAGE and GRADE : measure different parameters of the cancer and can be used to predict the likely course of the cancer
Criteria for grading: (compare ca cells to healthy orignal cells)
* Increasing anaplasia (poor cell differentiation + loss of morphology: irregularities in nuclear shape and resemblance to normal tissue.)
* Increasing mitotic activity (number of mitotes)
* Increasing genetic instability
Surgery
What are the aims? (4)
Treatment for solid tumours, can result in a complete cure. Followed by adjuvant chemotherapy.
- To remove the primary tumour
- To remove accessible isolated metastases
- To treat complications of cancer (hemorrhage, perforation, bowel obstruction, spinal cord compression)- Imaging techniques
- Reconstruct anatomical defects to improve function, cosmetic appearance, QOF
What is Preventative surgery?
What is Pre-emptive surgery?
Preventative surgery: removal of precancerous lesions, abnormal moles, colon polyps, pre-invasive forms of cancer
Pre-emptive surgery: prevent the disease in few rare cancers with a strong familial basis. E.g.:
-Colectomy for young asymptomatic patients with familial adenomatous polypitis mastectomy for double homozygous carriers of the BRCA1 and BRCA2 genes
Radiotherapy:
What is the aim?
How long it kill cancer cells?
Delivers a narrow beam of high-energy X-rays to a well-defined area of the body
Aim= Kill malignant cells by causing irreparable damage to their DNA→ cancer cells stop dividing or die→ they are broken down and removed by the body
Does not kill cancer cells right away: takes days or weeks of treatment before DNA is damaged enough for cancer cells to die (weeks or months after radiation)
Radiation doses are fractionated (delivered over a period of days):
- Allows any damaged normal tissues to repair themselves
- Tumour stem cells or quiescent G0 (not fully differentiated) cells: are resistant to radiotherapy
After radiotherapy→ tumour stem cells become reoxygenated and start proliferating. New doses destroy the reactivated tumour cells.
Reoxygenation: oxygen is required for the generation of the free radicals necessary to produce full effectiveness (oxygen effect)
Radiotherapy:
What is external beam radiation therapy?
What is internal radiation therapy?
-example?
What is systemic therapy?
- External beam radiation therapy: external machine aims radiation at cancer site
- Internal radiation therapy: source of radiation is inserted inside the body
-Brachytherapy: radiation from radioactive sources either placed close to or inserted in the tumour. Plastic-covered flexible iridium-131 wires can be inserted into tumours of the tongue, breast, brain and buccal mucosa - Systemic therapy: treatment travels in the blood to tissues killing cancer cells
Represents a component of anti-cancer treatment for ~40% of all cancer patients
Adjuvant, neo-adjuvant, palliative
