2124 zyxwvutsrq lnfluence of Age, Prior Abdominal Surgery, Fraction Size, and Dose on Complications After Radiation Therapy for Squamous Cell Cancer of the Uterine Cervix A zyxwvu Patterns of Care Study zyxw Rachelle M. Lanciano, MD,* Karen Martz, MS,t Gustavo S. Montana, MD,$ and Gerald E. Hanks, MD* The 1973 and 1978 national surveys conducted by the Patterns of Care Study (PCS) for squamous cell cancer of the uterine cervix were combined to analyze factors as- sociated with complications after radiation therapy (RT). Overall, 1558 patients were reviewed, with a median fol- low-up of 43 months. Major complications (defined as ne- cessitating hospitalization for management) were seen in 152 of 1558 (9.8%) patients, with a 5-year actuarial rate of 14%. A number of pretreatment and treatment factors were analyzed with respect to complications. In univari- ate analysis, significant pretreatment and treatment fac- tors associated with an increase in complications in- cluded young age, prior laparotomy for staging, history of prior abdominal surgery, increasing stage, use of exter- nal RT, high fraction size, cesium source, and high para- central (PCS point A) and lateral (PCS point P) doses. Multivariate analysis showed a history of prior abdomi- nal surgery, paracentral dose greater than zyxwvu 7500 cGy, use of cesium, daily fraction size greater than 200 cGy, and age younger than 40 years to be associated independently with complications. A detailed analysis of the type of and time to complications is presented. The knowledge and skillful management of these pretreatment and treat- From the *Department of Radiation Oncology, Fox Chase Cancer Center/University of Pennsylvania School of Medicine, Phila- delphia, Pennsylvania; the tAmerican College of Radiology, Philadel- phia, Pennsylvania; and the $Department of Radiation Oncology, Duke University, Durham, North Carolina. Supported by the Division of Cancer Treatment, Contract CM 87275 (Gerald Hanks, MD, principal investigator), and the Agency for Health Care Policy and Research. Address for reprints: Rachelle M. Lanciano, MD, Department of Radation Oncology, Fox Chase Cancer Center, 7701 Burholme Ave- nue, Philadelphia, PA 191 1 1. Accepted for publication November 8, 1991. ment factors may improve the therapeutic ratio for RT, which is the most active curative modality against cervi- cal cancer. Cancer 1992: 69:2124-2130. Radiation therapy (RT) remains the most active modal- ity in the treatment of squamous cell cancer of the uter- ine cervix. Unfortunately, large studies describing the influence of various patient, tumor, and treatment fac- tors on the complication rates are few, and, to our knowledge, no study presents a multivariate analysis of these factors. Because new strategies to intensify the radiation response are being studied, such as radiation- sensitizing drugs and hyperfractionated radiation, it is important to have a baseline complication rate for stan- dard RT and knowledge of the factors that may increase this rate. In a previous communication of the Patterns of Care Study (PCS) for squamous cell cancer of the uter- ine cervix,' tumor, patient, and treatment factors asso- ciated with decreased local control were described so that new strategies could be developed for patients with a poor outcome. This article describes an analysis of factors associated with an increase in complications after RT and establishes a national benchmark of com- plication rates in this same cohort of patients. Materials and Methods zyxw Stat istical Design The PCS constructed a master list of all RT facilities in the United States in 1973 and 1978. A number of facili- ties were selected randomly from each stratum of prac-