On Instagram, Jowell’s daughter-in-law Ella Mills, better known by her blogger name Deliciously Ella, revealed the ex-Culture Secretary was diagnosed with the disease back in May.
In a separate Twitter post, Jowell, who played a pivotal role in securing the London Olympics, said she was pledging to help other people with cancer live better lives for her 70th birthday.
But what is brain cancer and would you know how to spot the symptoms?
What is brain cancer?
Dr Clare Morrison, from online doctor MedExpress, explained that brain cancer results from “abnormal growths of cells in the brain”.
“They can arise from primary brain cells, or from the growth of cancer cells that develop in other organs and have spread to the brain by the bloodstream,” she told HuffPost UK.
While most growths that occur in the brain are called brain tumours – and we sometimes refer to brain cancer simply as a brain tumour - not all brain tumours are cancerous.
Martin Ledwick, Cancer Research UK’s head information nurse, explained the difference between the two.
“Benign brain tumours are non-cancerous, grow slowly and do not tend to invade tissues around them,” he told HuffPost UK.
“A brain tumour that is malignant is brain cancer and these tumours grow more quickly and can invade tissues next to then. Malignant brain tumours are often graded between 1 and 4 depending on how aggressive they are.”
According to the NHS, around 5,000 people are diagnosed with a primary malignant brain tumour in the UK each year.
There are 130 different types of brain tumour, which are usually named after the type of cell they develop from or the area of the brain they are growing in.
What are the symptoms of brain cancer?
According to Ledwick, symptoms of brain cancer “vary depending on the position in the brain and are usually related to the tumour causing pressure”.
“They can range from headaches, visual problems, drowsiness to seizures,” he said.
But he warned that “many of the symptoms can be caused by other illnesses too”, meaning if you experience any one of these symptoms it does not necessarily mean you have brain cancer.
Dr Morrison added: “General symptoms of brain cancer include severe headaches, seizures, personality or memory changes, vomiting, fatigue, drowsiness and sleep problems.”
If you’re concerned about any of these symptoms, visit your GP who may refer you for brain scans in order to complete diagnosis.
What causes brain cancer?
The exact cause of most brain cancers is unknown, but according to Cancer Research UK there are several factors known to increase an individual’s risk of the disease.
Although brain tumours can occur at any age - and some types of brain tumour are more common in children - our overall risk of brain cancer increases with age.
Exposure to radiation is also thought to be linked to the production of brain tumours, as is having childhood cancer.
“There is some evidence that there is an increased risk of brain tumours in adults who have had other types of cancer but more research is needed to confirm this,” the website states.
“The increase in brain tumour risk might be due to the treatment for the previous cancer, such as radiotherapy to the head.
“Having the chemotherapy drug methotrexate into the fluid around the spinal cord (intrathecal methotrexate) has been shown to increase the risk of brain tumours. Methotrexate is used to treat leukaemia, a type of blood cancer.”
Statistics suggest having a parent, brother or sister who’s had brain cancer also increases your risk of the disease, as does being diagnosed with HIV.
Finally, being overweight or obese has been linked to an increased risk of some kinds of brain cancer.
What is the treatment for brain cancer?
Treatment for brain cancer varies depending on the nature of the tumour the patient is diagnosed with.
“Options depend on the size, type and grade of the tumour, whether it’s putting pressure on vital parts of the brain and if it’s spread or not,” Dr Morrison said.
“For higher-grade tumours, treatment begins with surgery, followed by radiation therapy and/or chemotherapy.”
Around 40% of people who receive radiotherapy to treat brain tumours go on to experience ‘early delayed syndrome’, where symptoms include poor appetite, sleepiness, lack of energy and worsening of your old symptoms.
These side effects usually subside within six weeks, but patients are sometimes prescribed steroids to relieve symptoms.
Although the effectiveness of treatment will vary depending on the nature of the brain tumour, generally around 15% of people with malignant brain tumours will survive their cancer for five or more years after diagnosis.