Surgical wound infection and cancer among the elderly: a case control study. Surgical wound infection occurs in fewer than 5% of operations. Nevertheless, it represents the second most common type of hospital-acquired infection and results in increased morbidity and mortality. As with all nosocomial infections, the rate of surgical wound infection increases with age. Patients over 65 years of age run an approximately 15% risk of surgical wound infection. Two-thirds of patients with invasive cancer other than non-melanotic skin cancer are aged 65 years and over. Over half of them are treated surgically for their cancer. Cancer and other chronic diseases have been cited as possible causes of the increased risk of nosocomial infection among the elderly. Using the Foothills Hospital Wound Study Data Base as the sampling frame, we conducted a case-control study of surgical wound infection and cancer among the elderly. Cancer was found not to be a risk factor for surgical wound infection. The results are discussed in relation to the role of immunity in both disorders. 