Women respond well to radiotherapy but side effects are brutal

One of Australia's most experienced radiation oncology medical physicists, Professor of Medical Radiation, Dr Eva Bezak from the University of South Australia's said women are generally more sensitive to radiation than men, but this is not considered in international guidelines for radiation dosages.

Current guidelines are generally based on a person's height, weight or BMI, and radiobiological responses of the general population.

Because they are more radio-resistant than women, men's healthy tissues are better protected when receiving radiotherapy with fewer side effects, but their long-term survival rates are shorter.

In a paper published in Critical Reviews in Oncology/Hematology, Professor Bezak and her colleagues Louis de Courcy from University College Dublin and Professor Loredana Marcu from the University of Oradea in Romania highlight the need for gender to be taken into account when administering radiation.

"It is clear that gender plays a role in the occurrence and response to therapy of many diseases," Professor Bezak said.

"For example, it is already well established that men are more susceptible to head, neck and blood cancers and women are more prone to auto immune diseases as well as developing osteoporosis."

Scientists also know that individual responses to radiotherapy are up to 80 per cent determined by genetics.

"The next step is to ensure that we use both male and female mice even in our pre-clinical testing so we can get a better understanding of how gender influences treatment outcomes," said Professor Bezak.

"It is also important to collect data retrospectively so we can compare the radiotherapy outcomes for men and women who were prescribed radiotherapy for the same cancer."

The differences in radiation responses are highlighted by two major events in history: the Chernobyl nuclear reaction disaster in 1986 and the atomic bombings of Hiroshima and Nagasaki in 1945.

Professor Bezak said following Hiroshima and Nagasaki, the incidence of cancer in Japan was much higher in women (58 per cent) compared to men (35 per cent).

Likewise, after the Chernobyl nuclear accident, millions fewer girls were born to irradiated men and women were at greater risk of endocrine imbalance, thyroid cancer and brain tumours.

The one area that does appear to give women some protection against radiation is the female hormone oestrogen, which has a neuroprotective effect during head irradiation.

"As healthcare becomes progressively more tailored to the individual, gender is a factor that can no longer be disregarded. It needs to be taken into account as an independent prognostic factor," Professor Bezak said.