Pensioners who visit a GP with unexpected weight loss should be referred for urgent tests to investigate for possible cancer, researchers have said.

The call comes after a study found over-60s who go to their family doctor after unintentionally shedding weight have a greater than 3% chance of having one of 10 cancers.

These patients "warrant rapid investigation" for cancer and possibly multiple types, according to research published in the British Journal of General Practice.

The study, the first systematic review of existing evidence, found the risk with weight loss increases with age and if another sign of cancer is present.

As a symptom of cancer, weight loss was recorded as the second highest risk factor for colorectal, lung, pancreatic and renal and myeloma cancers, and the third highest in non-Hodgkin's lymphoma and gastro-oesophageal.

It was also linked with an increased risk of having ovarian, prostate and biliary tract cancers.

The review suggests patients aged 60 and over who present to primary care settings with "weight loss that prompts a clinical record entry warrant rapid investigation for possible cancer, potentially across multiple sites," the researchers said.

They added: "Investment in rapid diagnostic pathways to urgently investigate weight loss across a number of cancer sites is justified."

The findings come a week after NHS England announced a trial of "one-stop shops" for cancer diagnosis.

Under the initiative, GPs can refer patients suffering from "vague" symptoms, including unexplained weight loss, to assessment centres to undergo multiple tests for different cancers.

The scheme, piloted in 10 areas, aims to speed up diagnosis in those not showing signs for a specific type of cancer.

Dr Richard Roope, clinical lead for cancer at the Royal College of GPs, said: "GPs will always be vigilant when presented with any symptom that could indicate cancer, including unexplained weight loss, whilst recognising that this could be a symptom of many other, more common conditions.

"Currently there are no clinical guidelines to support GPs and their teams in how to respond to or investigate patients who present with weight loss, without other symptoms, in the cancer setting.

"These important findings present strong evidence of the correlation between significant unexplained weight loss and many cancers, and should certainly be taken on board as clinical guidelines for GPs and healthcare professionals are updated and developed.

"We agree with the researchers' recommendations that GPs need better access to diagnostic tools in the community across the UK so that we can appropriately refer patients to either rule out or confirm a diagnosis of cancer, as currently our access is among the lowest in Europe."

The research was carried out by experts from the Nuffield Department of Primary Care and Health Sciences at the University of Oxford and University of Exeter's Medical School.