Treating cancer
Treatment of cancer can include surgery, chemotherapy, radiation therapy or newer therapies such as using monoclonal antibodies.
Chemotherapy treatment
A patient undergoes chemotherapy for cancer. Chemotherapy aims to shrink or halt the growth of the primary cancer. It is administered in a variety of ways, depending on the type of cancer. The most common methods are intravenously (through a vein) or orally (as pills or liquids).
Surgery
Surgery involves the removal of a tumour or the tissue in which it is found. One example is a lumpectomy, where just the tumour is removed from a breast, or a mastectomy, where the whole breast is removed. How successful the surgery depends on whether or not the cancer has spread to other parts of the body. If it moves to a different part of the body, such as through the blood or lymphatic system, even a single cancer cell could grow into a new tumour and cause a recurrence of the cancer.
Excision of a carcinoma
Surgical excision of a carcinoma.
A pathologist will examine the tissue that has been removed to determine the amount of normal tissue and the likelihood that there are other cancer cells still in the patient’s body.
Chemotherapy
Chemotherapy works by targeting cells that are dividing rapidly, by interfering with cell division or DNA synthesis. It is called a systemic treatment in that it also aims to get rid of any cancer cells that might have spread to the rest of the body. Chemotherapy is effective because the drugs work against rapidly dividing cancer cells.
Unfortunately, the body has many different kinds of rapidly dividing cells which means the chemotherapy will affect them too – these are known as side effects. As chemotherapy can also affect normal tissue that is fast growing such as the hair follicles on your head or the lining of your intestines, some of side effects are hair loss or nausea.
Radiotherapy
Early after the discovery of X-rays, it was discovered that, along with other forms of ionising radiation, they could be used to treat cancers. X-rays damage the DNA in the cancer cell leading to cell death.
Cells are more vulnerable to dying when they are in the process of cell division, so tissues that are dividing rapidly, like cancer cells, are more likely to be killed. Ionising radiation also has an effect on normal cells, which can lead to side effects and the rare possibility of new tumours. However, normal cells have better DNA repair mechanisms than cancer cells, so the radiation treatment is carefully planned to give the normal tissue enough time to recover between treatments. Damage to normal tissue is also minimised by targeting the radiation as close to the tumour as possible.
Modern radiation therapy techniques can use imaging technology to create a 3D model of the tumour and use this in the targeting of radiation beams. Radiation can also be given internally to a patient by inserting beads of a radioactive material directly into a tumour. Patients also have custom-made radiation masks to keep their head and neck still to help ensure that the radiation is delivered to a precise place.
Radiation therapy room
This is a radiation treatment room, showing some of the medical equipment used to treat cancer patients. On the left is the large radiation machine and to the right a radiation mask that covers the patient’s head and upper body during treatment.
Monoclonal antibodies
This treatment uses the body’s own defences against the cancer. This includes the use of monoclonal antibodies, where a cell that is producing antibodies against a protein that is associated with cancer cells is cloned to create a cell line that produces identical antibodies.
The drug Herceptin is an example of the use of such antibodies. Human epidermal growth factor receptor 2 or HER2 is a protein produced by the HER2 gene. HER2 protein is found in most normal epithelial including normal breast cells, the gastrointestinal tract and skin. It transmits a signal telling the cells to divide.
In one type of breast cancer, there is an excessive amount of HER2 protein on breast cells, which means the cells are bombarded with messages to divide. Herceptin is a monoclonal antibody targeting this protein. It seems to work in two ways – it stops the HER2 protein from transmitting the message to divide to the cell nucleus, and it marks the cell for destruction by the body’s immune system.
Monoclonal antibodies can also be used to target cancer cells in chemotherapy or radiation therapy by attaching a radio nucleotide or chemotherapy drug to an antibody that is targeting a particular cancer protein.
Different types of therapies may be combined for greater effectiveness. For example, before surgery, chemotherapy or radiation therapy may be used to shrink the tumour to make it easier to remove, or after breast removal, a woman might be given Herceptin to mop up any HER2 positive cells that might have escaped and started to form a tumour elsewhere.
Ongoing drug development and gene research
Research is ongoing into a number of other future possible treatments for all types of cancer.
International research is exploring Chimeric Antigen Receptor T-cell therapy (CAR T-cell therapy) to treat cancer. This is a treatment where a patient’s immune cells (T cells) are genetically modified and then returned to them, where they can attack and destroy cancer cells.
In Australia, the USA and parts of Europe and Asia, CAR T-cell therapies are licensed for routine use for some cancers. As of 2026, they not currently available in New Zealand, but clinical trials are being undertaken here.
The Malaghan Institute of Medical Research is leading a major trial to develop and test its own CAR T-cell therapy for patients with lymphoma. Learn more about the therapy here.
Related content
Learn more about cancer and hear from a pathologist who diagnoses cancer in What is cancer.
Explore cancer risk factors here.
These articles explain more about skin cancer, some of the risk factors and how skin cancer is diagnosed and treated. Investigate three different forms of skin cancer in Melanoma, Basal cell carcinoma and Squamous cell carcinoma.
Activity ideas
In these activities students can explore cancer screening and diagnosis, the characteristics of normal and cancerous cells and cancer definitions.
These activities are designed to explore skin cancer and UV:
UV bead items – students design and make an item from UV beads that children could easily wear or carry to monitor their exposure to UV.
Investigating sunscreens – students use UV beads to investigate the effectiveness of different sunscreen lotions.
Investigating UV intensity – students use UV beads to investigate the intensity of UV rays in a range of different situations.
The face of melanoma – students examine the lifestyle factors that contribute to skin cancer and prepare information about skin cancer for a child or teenage audience.
Useful links
Te Aho o Te Kahu Cancer Control Agency is a government agency created in recognition of the impact cancer has on the lives of New Zealanders.
Find out more about cancer with the New Zealand Cancer Society.
Learn more about the effects of chemotherapy on the body with this virtual guide from Healthline.com.
David Ackerley and Janine Copp from Victoria University are engineering microbes to produce prodrugs that could help kill cancer cells, find out more in this RNZ interview.
