Quantifying the impact of pre-existing conditions on the stage of oesophagogastric cancer at diagnosis: a primary care cohort study using electronic medical records.

Diagnosing cancer is complicated by existing medical conditions. Diagnosis may be delayed if conditions explain cancer symptoms, or dominate appointments. Diagnosis may be quicker if conditions increase doctor­patient contact. We studied the association between existing illness and stage (early or advanced) of diagnosis with cancer of the stomach or gullet. We studied the primary-care records of patients aged ≥40 years, diagnosed in 01/01/2010­31/12/2015, and got stage from English cancer registry data. We searched the primary-care records for cancer symptoms (e.g. difficulty swallowing), and for 27 conditions that were common or explained cancer symptoms (e.g. difficulty swallowing following a stroke). We analysed cancer stage, looking at age, sex, multimorbidity (two or more conditions) and explanations for symptoms. We studied 1749 patients, of whom 1265 (72.3%) had advanced-stage cancer. The chance of advanced stage was similar in women with (71%, 95% CI 66­75%) or without (69%, 62­76%) multimorbidity. It was lower for men with (70%, 67­74%) than without (79%, 75­83%) multimorbidity. Stage of cancer was not affected by having explanations for cancer symptoms. In summary, for men, multimorbidity is associated with a reduced chance of advanced-stage cancer of the stomach or gullet to levels seen collectively for women.