Hyperthermia as a cancer treatment
Dr Carrie Minnaar informs us about hyperthermia, a new treatment in South Africa, and its benefits when used alongside chemotherapy and radiation.
Hyperthermia explained
Hyperthermia describes an increase in the tumour temperature above the normal physiological temperature range. A complex set of reactions of the tumour cells and environment in response to the heat results in improved tumour destruction.
How does it help?
Possibly the most important response is the change in blood flow to the tumour. In an attempt to lower the temperature at the tumour site, the body responds by increasing the blood flow and oxygen to the heated area. While this may seem counter-productive, it is actually very helpful when combined with cancer treatments. Increased blood flow increases the delivery of chemotherapy to the tumour and the increased oxygen inside the tumour environment improves the cell-killing effects of radiation therapy. This is especially helpful in larger tumours that have a poor blood supply, in tumours that recur in areas previously treated with radiation therapy, and in regions where the blood supply is restricted.
Increasing the heat of the tumour also induces an inflammatory response at the site of the tumour which further assists in the fight against the tumour. The increased heat has some direct damaging effects on the tumour cells, which in some instances may assist in the destruction of the tumour cells.
Another way that hyperthermia can assist in the fight against cancer is by slowing down and impeding the cancer cells’ ability to repair from the damage done by radiation or chemotherapy. Under heated conditions the normal repair mechanisms are not able to occur as effectively and as quickly.
What kinds of hyperthermia techniques are used?
A wide variety of heating technologies have been developed over the years to heat the tumour (local hyperthermia), a region, or the whole body. Devices can use radio waves, microwaves, infra-red, or ultrasound to apply heat externally, or internally after being inserted into the body using probes.
Intravesical hyperthermia
Some urologists in South Africa are performing this technique for the treatment of bladder cancer. It involves the insertion of a catheter into the bladder through the urethra. The specialised catheter has a radiofrequency-emitting tip which can heat bladder tumours from the inside.
Externally generated radiofrequency local hyperthermia
This is currently only offered at the Wits Donald Gordon Medical Centre in Gauteng. The device uses an amplitude modulating (electronic communication) technology to apply very mild heat at a very low power which means that the treatment is extremely safe.
Side effects are rare and may include a small superficial skin or fatty tissue burn. The treatment takes an hour, during which time the patient lies comfortably on the bed and can catch up on some sleep. Unfortunately, the technology is still very new in South Africa and reimbursement from the medical schemes is still limited.
When is it administered?
It is usually given in combination with radiotherapy or chemotherapy, on the same day, immediately after receiving the treatment.
What tumours are eligible?
Not all tumours are eligible for hyperthermia. Many cancers respond very well to standard treatments and it is therefore not necessary to add hyperthermia to the treatment protocol.
Tumours that may benefit from hyperthermia include tumours that are known to be resistant to treatments or are difficult to treat. These include certain kinds of recurrent breast cancers, locally advanced cervical cancers, soft tissue sarcomas, some head and neck tumours, and a few others.
For more information on which specific tumours could benefit from hyperthermia, you need to speak to your oncologist.
For more info, please visit www.onc-hyperthermia.co.za
References:
- Local hyperthermia combined with radiotherapy and-/or chemotherapy. Cancer Treatment Reviews, 2015;41(9):742–753.
- The effect of modulated electro-hyperthermia on local disease control in HIV-positive and -negative cervical cancer women in South Africa. PLoS ONE 2019;14(6):.e0217894.
- Review of the Clinical Evidences of Modulated Electro-Hyperthermia. Frontiers in Oncology 2019; 9:1012
MEET OUR EXPERT – Dr Carrie Minnaar
Dr Carrie Minnaar first studied hyperthermia in Germany in 2009 and completed her PhD on hyperthermia in oncology at Wits in 2019. Currently, Dr Minnaar practices oncologic hyperthermia at the Wits Donald Gordon Medical Centre.