| Conventional diagnosis |
CRC in situ is deceiving in diagnosing owing to their anatomical presentation and small size, hence they easily overlooked and usually only detected at later stages when a patient develops symptoms |
8 and 9
|
| Stool-based tests |
• Non-invasive |
6
|
| • However, lack sensitivity for early stage diagnosis and are costly |
| Visual examination tests |
• Less costly |
6, 8, 16 and 17
|
| • Allows simultaneous visualization of the entire distal colon, as well as allows for biopsy sampling |
| • However, invasive, lacks the sensitivity in identifying smaller CRC lesions and unable to discriminate between a benign versus invasive carcinoma |
| Blood and biopsy tests |
• More specific for detection |
21
|
| • However, invasive and reliability of biomarkers for early CRC diagnosis is questionable, since they are usually only found overexpressed in progressive late stages of CRC |
| Conventional treatment |
The effectiveness of treatment modalities is highly dependent on the stage and size of tumor. However, even though these treatment modalities are developed to circumvent CRC, they still yield harmful effects post-treatment |
6 and 23
|
| Surgery |
• Success dependant on tumor location, as well as the presence and degree of metastasis |
6, 7, 11 and 24
|
| • Generally effective within the early stages, especially if the tumor is small and localized in lesions that have not migrated to other organs |
| • However, if cells are shed into the circulatory system during surgery or parts of the lesion remain unresected, this can potentially trigger tumor recurrence or spread after excision |
| • Associated with pain and tenderness |
| Radiation |
• Successfully, used to shrink tumors abnormal growth, in order to facilitate an easier excision during surgery |
2, 6 and 24
|
| • However, causes DNA material destruction in healthy tissue cells and causes side effects, such as bowel dysfunction, nausea, bladder dysfunction, fatigue and skin irritations |
| Chemotherapy |
• Mostly noted improved survival rates in early diagnosed patients and when used in combination with radiation |
2, 16 and 24
|
| • However, can have a poor outcome in late diagnosed patients |
| • Adverse side effects such as hair loss, vomiting, diarrhea, nausea and unwanted side effects on healthy tissues |
| Immunotherapy |
• Keytruda (pembrolizumab) and Opdivo (nivolumab) have reported significant anticancer activity |
3 and 6
|
| • However, most drugs are novel and many of these treatments are still in clinical trials and so unavailable to patients at present |
| • Furthermore, drugs are expensive and have been associated with post-therapeutic complications such as fatigue, nausea, disorientation and death if administered incorrectly |
| Photodynamic diagnosis and treatment |
Most prominent advantage is that via blue and red-light colonoscopy, can be specifically designed to be highly selective in identifying, as well as combatively targeting and treating cancer cells, without damaging adjourning tissues, as well as allow for multiple dosage administration with negligible side effects being observed. Treatment is localized with minimal side effects to surrounding tissues. However, this method is still in early stages of research and still requires clinical approval |
28, 29 and 33
|
