Appendix Cancer Rates Surge Among Younger People Globally Appendix cancer is rising sharply in people under 50, with cases increasing 71 per cent in a decade in the US and five-fold in the UK. Researchers probe causes and call for early diagnosis. Appendix cancer is increasingly being diagnosed in younger people worldwide, with statistics showing a dramatic rise in cases among those under 50. The disease, which affects the four-inch-long organ connected to the bowel, is outpacing other fast-growing cancers such as bowel cancer. A US study last year found that people aged 29 to 44 were now the most likely to develop tumours in their appendix, with cases rising 71 per cent in just ten years. In the UK, researchers from Bristol in 2022 reported that the incidence of appendix cancer increased five-fold between 1995 and 2016, with the biggest rises among those aged 20 to 39. Rising Incidence of Appendix CancerWhile appendix cancer remains rare overall, with just 1.6 cases per 100,000 people in Britain, the upward trend is concerning. The Bristol researchers described the increase as a cause for concern. The disease is difficult to diagnose because it can progress without symptoms or with vague symptoms such as mild abdominal pain and bloating. As a result, many cases are picked up only after the cancer has spread, making treatment harder. Relapse is common, and around half of patients do not survive five years if diagnosed at an advanced stage.Treatment can involve extensive abdominal surgery and a procedure to bathe the abdomen in chemotherapy to kill remaining cancer cells. This gruelling regimen can leave women infertile. Professor Omer Aziz, who leads the appendix cancer unit at The Christie NHS Foundation Trust in Manchester, one of two national specialist centres for the disease, said he is definitely seeing younger and younger people developing cancer. Tim Brill, a trustee of the appendix cancer charity Pseudomyxoma Survivor, described the trend as worrying and called for more research to drive early diagnosis and better treatments.Understanding the Appendix and Its CancerThe appendix remains something of a mystery. Situated in the lower right of the abdomen, it is thought to play a role in the gut's immune system and in helping to clear waste from the body. A 2025 review published in the leading journal Nature emphasised how little is known about the causes of appendix cancer, branding it an enigma. However, there are clues to what may be driving some of the headline figures, and the good news is that those are mainly reassuring.One key factor is that more early-stage cancers are being detected when people have surgery to remove their appendix, a procedure known as an appendectomy. These cancers tend to be the most common type to affect the appendix, known as neuroendocrine tumours, or NETs, which start in cells involved in hormones and signalling. They tend to be small and slow growing, and once removed along with the appendix often need no further treatment.Appendectomies and WHO Classification ChangesOver the years, the number of appendectomies has risen steadily, giving doctors more opportunities to find these previously hidden tumours. In England, for instance, 10,000 more such operations were carried out in 2016 compared with 1999. Because people having their appendix removed are often relatively young, this may help explain some of the rise in diagnoses.In parallel, the World Health Organization (WHO) has changed the way such tumours are classified. Before 2000, they were often called carcinoids and were thought to be benign or at least less aggressive. But research suggesting they could grow and become malignant meant that from 2000 onwards, WHO guidelines introduced new terminology to describe them as NETs, meaning they were recorded as cancer for the first time. The result was an inevitable increase in cancer statistics. The Bristol study concluded that the rising tide of UK diagnoses was being driven largely by an increase in these NETs being picked up at grade one, the earliest cancer stage.Professor Aziz said that previously, if a clinician saw something odd in an appendix when it was being removed, it would not be investigated. Now it is sent off to be studied. This shift in practice, along with the classification change, has contributed to the higher numbers. Despite the rise, experts emphasise that the overall risk remains low and that more research is needed to understand the causes and improve outcomes.