title: Radiation therapy improves survival in rectal small cell cancer - Analysis of Surveillance Epidemiology and End Results (SEER) data.
abstract: BACKGROUND
  Small cell carcinoma of the rectum is a rare neoplasm with scant literature to guide treatment. We used the Surveillance Epidemiology and End Results (SEER) database to investigate the role of radiation therapy in the treatment of this cancer.
  
  
  METHODS
  The SEER database (National Cancer Institute) was queried for locoregional cases of small cell rectal cancer. Years of diagnosis were limited to 1988-2010 (most recent available) to reduce variability in staging criteria or longitudinal changes in surgery and radiation techniques. Two month conditional survival was applied to minimize bias by excluding patients who did not survive long enough to receive cancer-directed therapy. Patient demographics between the RT and No_RT groups were compared using Pearson Chi-Square tests. Overall survival was compared between patients who received radiotherapy (RT, n = 43) and those who did not (No_RT, n = 28) using the Kaplan-Meier method. Multivariate Cox proportional hazards model was used to evaluate important covariates.
  
  
  RESULTS
  Median survival was significantly longer for patients who received radiation compared to those who were not treated with radiation; 26 mo vs. 8 mo, respectively (log-rank P = 0.009). We also noted a higher 1-year overall survival rate for those who received radiation (71.1% vs. 37.8%). Unadjusted hazard ratio for death (HR) was 0.495 with the use of radiation (95% CI 0.286-0.858). Among surgery, radiotherapy, sex and age at diagnosis, radiation therapy was the only significant factor for overall survival with a multivariate HR for death of 0.393 (95% CI 0.206-0.750, P = 0.005).
  
  
  CONCLUSIONS
  Using SEER data, we have identified a significant survival advantage with the use of radiation therapy in the setting of rectal small cell carcinoma. Limitations of the SEER data apply to this study, particularly the lack of information on chemotherapy usage. Our findings strongly support the use of radiation therapy for patients with locoregional small cell rectal cancer.
authors.affiliation: Medical Scientist Training Program, New York, USA. Aram.Modrek@med.nyu.edu.
authors.forename: Aram S
authors.initials: AS
authors.lastname: Modrek
authors.affiliation: Department of Radiation Oncology, New York, USA. Howard.C.Hsu@Lahey.org.
authors.forename: Howard C
authors.initials: HC
authors.lastname: Hsu
authors.affiliation: Division of Hematology and Medical Oncology, Department of Medicine, New York University School of Medicine, New York, USA. Cynthia.Leichman@nyumc.org.
authors.forename: Cynthia G
authors.initials: CG
authors.lastname: Leichman
authors.affiliation: Department of Radiation Oncology, New York, USA. Kevin.Du@nyumc.org.
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Du
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018906:Antineoplastic Agents, Alkylating / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D018288:Carcinoma, Small Cell / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D003131:Combined Modality Therapy; D013505:Digestive System Surgical Procedures; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009944:Organoplatinum Compounds / Q000008:administration & dosage; D016016:Proportional Hazards Models; D012004:Rectal Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D012189:Retrospective Studies; D018426:SEER Program; D016019:Survival Analysis; D014481:United States / Q000453:epidemiology
chemical_list: D018906:Antineoplastic Agents, Alkylating; D009944:Organoplatinum Compounds