The group, which is based at Crawley Hospital but started in Horsham where they still have a hub at the hospital, were announced as one of the winners of the prestigious award in June, along with other voluntary organisations.
Mrs Susan Pyper, Lord-Lieutenant of West Sussex, led the presentations at Ram Sports and Social Club with support from Deptuy Lieutenant and High Sherioff Neil Hart and Paul Legrave, The Officer to the West Sussex Lieutenancy.
And in her speech, Mrs Pyper explained how much groups like Olive Tree had to go through and emphasised what an achievement this award is.
"This is a really significant event tonight," said Mrs Pyper.
"The Queen’s Award for Voluntary Service is the MBE for Voluntary Groups. It’s not just a ‘You’ve Done Well’ certificate. It’s so much more than that.
"And don’t think for a moment all you have to do is apply for QAVS and get it. They all come through my office. And all the applications I ask two Deputy Lieutenants to go and visit the organisations once, twice or even three times and find out everything about it, it’s a bit like an Ofsted inspection.
"They go in and have a look at every aspect of. They look at the feel of it but also look at the bottom line, the numbers, who is doing what.
"It’s a thorough process.
"They then write a report which comes to me and I look at it and talk to them. Then I write a report and send it up to London, to the cabinet office. They have committees of people who look at this. Olive Tree is committed to provide support to cancer sufferers and there will be a committee that speciality slots into so it will be looked at again then.
"I want you to know that you have been through quite a lot and you have achieved excellence.
"So from all those who have arrived at my desk to start off with a small fraction end up having an evening like tonight.
"It’s prestigious and the work that you do, it changes lives and all of you as volunteers must have seen that and sensed it."
"There is a fear and stigma that often surrounds cancer that a lot of us have had with relatives and ourselves have had, it’s frightening. Your whole world is turned upside down.
"But look at the warmth of this group. Everyone of you has given your time to help people ion that journey while they are suffering from cancer. Thank you. What more can anyone say? Thank you on behalf of the Queen.
"This award, be really proud of it. You are allowed to be proud of yourselves now and then and this belongs to all of you."
Mr Hart read the citation from The Queen at the event before Mrs Pyper presented the award to Brenda Miller, a counsellor and supervisor at Olive Tree.
Mrs Miller said: "I was very honored to be asked to accept this on behalf of the volunteers at the Olive Tree. It’s for everybody past and present.
"We couldn't do our job if it wasn't for Marilyn, Lisa, Terry and Jackie and also our Trustees, they guide us. The Olive Tree has come such a long way from when I first started when it was started around a kitchen of our founder member in Horsham and she recognised a lot of people were coming from Crawley. I have seen it grow, and grow and grow."
Mrs Miller added: "I looked up Olive Tree on Google and it said they last on average for 500 years, hopefully in the next 500 years they will find a cure for cancer."
Earlier in the evening, Olive Tree Cancer Support President and former BBC newsreader Nicholas Owen presented all the volunteers with their QAVS badges,
Gurjar Hindu Union and Streetlight UK were also named as QAVS winners in June.