Doctor: I'm afraid I have some bad news and some even worse news from the test results.
Patient: Give me the worst news first, doc.
Doctor: You have cancer.
Patient: OMG! What's the other news?
Doctor: You have Alzheimer's.
Patient: Thank God for that! For a moment there I thought you were going to tell me I had cancer.
Luckily, new research suggests that you're unlikely to suffer from both these diseases at the same time - and scientists claim that Alzheimer's disease actually wards off cancer, while cancer sufferers can cheer themselves up with the knowledge that they're less likely to forget to put their pants on.
US researchers studied 3,020 people aged 65 and over for a study published in Neurology.
Those who had Alzheimer's were found to be 69 percent less likely to develop cancer over the following five years.
In turn, those with cancer turned out to be 43 percent less likely to develop Alzheimer's within eight years.
But researchers at Washington University School of Medicine in St Louis say more work is needed before any firm conclusions can be drawn, adding that the findings also only seemed to apply to white people.
Lead researcher Dr Catherine Roe said that discovering the links between the two conditions may help to open up new avenues for possible treatments.
"Alzheimer's disease and cancer are both characterised by abnormal, but opposing, cellular behaviour," said Roe. "In Alzheimer's disease, excessive cell death occurs, whereas cancer is characterised by excessive cell growth… there are certain molecular pathways that may influence both Alzheimer's disease and cancer."