For most of the patients with cancer comorbidity had independent prognostic effect. This negative influence of comorbidity on survival of cancer might be due to several mechanisms: the increased risk of death due to the comorbid condition itself, more contra-indications for anti-cancer treatment, more indications for dose reduction and a higher rate of treatment-related complications, such as infections and cardiovascular events. It is known that in some chronic diseases (e.g., coronary artery disease, hypertension, and obesity) pro-angiogenic growth factors are increased compared to controls and mostly normalized after specific treatment. We propose that increased proangiogenic growth factor levels in cancer patients due to comorbidities may lead to the progression of the tumors and poor prognosis. Treatment of comorbidities besides the treatment of primary tumor may further increase effective management of cancer. (c) 2006 Elsevier Ltd. All rights reserved.