"Cancer champions" will encourage people to seek help for "vague" symptoms as part of a new campaign led by Cardiff University and funded by Cancer Research Wales.
The six-month campaign will target parts of South Wales with poor cancer survival rates and highlight six possible symptoms, including unexplained weight loss, loss of appetite, nausea, persistent fatigue, abdominal pain and "not feeling yourself".
The initiative aims to encourage adults in the Cwm Taf Morgannwg University Health Board area to contact their GP if they have had these symptoms for at least three weeks.
Professor Kate Brain, a health psychologist from Cardiff University, said it was vital to seek help early for "vague but concerning" symptoms.
As part of the campaign, trained "cancer champions" will raise awareness of non-specific cancer symptoms and support people to seek help from their GP. They will visit supermarkets, community centres, GP surgeries and pharmacies to offer help and support.
The campaign, which starts this month, will also promote the message that "Finding cancer early saves lives" via buses, Facebook and local radio.
Alongside the campaign, researchers from the University will assess whether it has been delivered effectively and whether people in local communities in Cwm Taf were aware of it.
They will also explore what the public thought of the TIC-TOC campaign - Targeted Intensive Community-based campaign To Optimise Cancer awareness - and the findings will be used to improve cancer services in Wales and the UK.
Chief investigator Professor Brain, from Cardiff University’s School of Medicine, said: "Cancer outcomes tend to be worse in economically-disadvantaged areas; barriers such as low awareness of vague symptoms, fear of cancer being diagnosed, or fear of cancer treatment can discourage people from seeking help early. As such, people in these areas may need extra support and encouragement to seek help for any concerning symptoms.
"We have developed a campaign designed to enable people to seek help early for cancer symptoms, particularly those which may seem vague but are still concerning, such as feeling tired all the time or losing weight for no reason.
"If you or someone you know is experiencing any unusual or persistent symptoms, then I would encourage you to contact your GP at the earliest opportunity. In most cases it won’t be cancer, but if it is, finding cancer early gives the best chance of successful treatment."
Ann Tate, CEO of Cancer Research Wales, said: "We have become acutely aware that traditional cancer awareness campaigns can often miss the target group, and any initial success they have tends to be short-lived and limited in nature. We are excited by the new approach the TIC-TOC study is undertaking, as it empowers the communities to look out for each other in a more holistic approach that involves the people, primary and secondary care in a more joined up manner.
"We hope the results from this study will provide a new and more meaningful framework from which all future cancer awareness campaigns are built, importantly saving lives through earlier diagnosis in the process."