The Ministry of Defence is now looking at how it can better support service personnel who are diagnosed with a significant illness.
But for Major Mandy Islam, her French Bulldog has been a vital support.
In July 2015 she was diagnosed with multiple myeloma, an extremely rare form of terminal blood cancer that affects the bone marrow.
We spoke to her about her ordeal, and how she’s managed to overcome adversity:
"My dog is my absolute wingman. He's always there sat with me. My dog has been phenomenal"
While there are many books out there about cancer, Mandy found that when she was diagnosed, none really reflected her experience.
It was because of this that she decided to write her own book, a project which she undertook during her gruelling treatment, about her cancer journey, which is due to be published later this year.
Mandy has served in the British Army for 21 years, with tours of Northern Ireland, Bosnia, Iraq and Afghanistan.
Although the armed forces are exempt from certain parts of employment legislation, Mandy's current role involves looking at policy and guidance.
While Mandy waits for her personal book to be published, she's set up a social media account called the 'Cancer Warrior Diaries'.
In just a month alone it's amassed more than 1,800 followers from across the world.
It is this sense of community through adversity that Mandy is now hoping to foster; away from operations, cancer is still the biggest killer of British military personnel each year.
Mandy now hopes her book and social media posts will bring those diagnosed with a significant illness together, and she's urging them and their families, to get in touch