Women have a 30% better chance of surviving the skin cancer melanoma than men, new research published in the Journal of Clinical Oncology suggests.
South Africa has the highest rate of skin cancer in the world after Australia, and is common in both men and women.
The analysis of four European studies found that by almost every measure, women can expect a better outcome than men following an early stage melanoma diagnosis. The difference in outcome is rooted in basic differences in gender biology, the researchers suggest.
“The 30% advantage applies to survival,” said study author Dr Arjen Joosse, from the department of public health at Erasmus University Medical Centre in Rotterdam, the Netherlands. “It also applies to having a metastasis [spread]: women have a 30% lower chance to experience a metastasis to the lymph nodes and to other organs.”
Joosse noted that the fact that women tend to fare better than men following a melanoma diagnosis is a well-established observation based on prior research. However, the reasons behind the prognosis gap have remained elusive. And the new research found an association between gender and melanoma survival, not a cause-and-effect.
Joosse and his team analysed data on nearly 2700 melanoma patients from four different melanoma treatment trials conducted in Europe.
All of the male and female melanoma patients had been diagnosed with either stage 1 (early) or stage 2 (localised) cancer. During and following treatment, all the patients were tracked for disease remission, relapse, spread and death.
The result: male melanoma patients were found to have worse disease characteristics at diagnosis and worse disease progression.
On the latter measure, female patients were found to have a “highly consistent and independent advantage” over men in terms of overall survival, both before and after menopause.
It is not that the initial tumour starts out worse in men than women, the authors stressed. Rather it is something gender-related that causes the cancer to unfold in a more deadly way in men. In theory, oestrogen level differences could play a role, although the team noted that the evidence so far suggests the hormone does not have much effect on melanoma. Other possibilities include gender differences with respect to vitamin D metabolism, immune system function, male testosterone levels and what is known as “oxidative stress” in the body.
“I believe that the message here is that if you’re a man, think like a woman,” said Dr Vernon Sondak, chair of the department of cutaneous oncology at the Moffitt Cancer Centre in Florida in the United States in an accompanying editorial. “And that’s because most of us feel that a big part of this has to do with the fact that women are a little more likely to be paying attention to their skin and to notice something on their skin, and most importantly, to do something about it right away. And with melanoma, early detection is key,” he stressed.
“So, I think in large part this is a behavioural issue, not a genetic issue,” Sondak added. “However, that’s not the whole issue. It is also the case that what we now call melanoma, one disease, may actually be many different diseases caused by many different things. And with that there may be genetic differences, all else being equal, in how men and women get these different diseases in the first place. This study didn’t look at that. But that’s another important aspect to consider.”
Source: HealthDay News