The range of targeted therapies has increased exponentially in the last ten years in cancer care and continues to be the focus of much anticancer drug development.1 Targeted cancer therapies are drugs or other substances that interfere with specific molecules involved in cancer cell growth and survival. Targeted therapies are often cytostatic (they block tumour cell proliferation) whereas standard chemotherapy agents are cytotoxic (they kill tumour cells).1
Biological and molecular targeted therapies have therapeutic and supportive roles in cancer control:1, 2
- curative when used in the primary or adjuvant setting
- improve treatment response by improving disease free survival when used in conjunction with conventional therapies
- control or stabilise disease in advanced cancers in the palliative care setting
- maintain or enhance quality of life.
- minimise the severity of toxicities associated with other therapeutic treatments.
The mechanism of action underlying biological and molecular targeted therapies vary depending on the agent, and include:1, 3
- enhancement of the individual's immune system
- alteration of the environment in which cancer cells grow
- increasing the vulnerability of cancer cells to the body's immune system
- alteration of the pathway by which normal cells transform to malignant cells
- prevention of metastasis of cancer cells
- enhancing the repair of normal cells damaged by treatment
- changing cancer cells so they behave like healthy cells
- facilitating delivery of toxic therapies to cancer cells.
As knowledge develops regarding the hallmarks of cancer and enabling characteristics of cancer development and progression, mechanism based targeted therapies are emerging. Examples of this are provided in Table 1: Therapeutic Targeting of the Hallmarks of Cancer.
Table 1: Therapeutic Targeting of the Hallmarks of Cancer4
(Adapted from Hanahan, D. and Robert A. Weinberg, Hallmarks of Cancer: The Next Generation. Cell, 2011. 144(5): p. 646-674.)
|Hallmarks of cancer||Examples of therapeutic approaches|
|Resisting cell death||Proapoptotic BH3 mimetics|
|Deregulating cellular energetics||Aerobic glycolysis inhibitors|
|Sustaining proliferative signaling||EGFR inhibitors|
|Evading growth suppressors||Cyclin-dependent kinase inhibitors|
|Avoiding immune destruction||Immune activating anti-CTLA4 mAb|
|Enabling replicative immortality||Telomerase inhibitors|
|Tumour-promoting inflammation||Selective anti-inflammatory drugs|
|Activating invasion and metastasis||Inhibitors of HGF/c-Met|
|Inducing angionesis||Inhibitors of VEGF signaling|
|Genome instability and mutation||PARP inhibitors|
Targeted therapies, aspects of pharmaceutical and oncological managment5 Cancer Forum, 2013
Hallmarks of cancer: The next generation4 Cell, 2011
- Develop a definition of targeted therapy
- Outline how targeted therapy is different to conventional chemotherapy
Briefly describe how you would explain the role of targeted therapies to a nurse new to the field of cancer care.
Discuss some of the concerns that a person about to undergo targeted therapies may have about these treatments.