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?
How histologically similar is the tumour to the tissue of origin?
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
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
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?
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 88travels 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
