Myung Mi Cho1, John W Morgan, Raymond Knutsen, Keiji Oda, David Shavlik, Synnove Knutsen, Kevork Kazanjian. 1. 1Department of Epidemiology, Biostatistics, and Population Medicine, School of Public Health, Loma Linda University, Loma Linda, California 2Department of Surgery, Mutual Aid Association of Public School Teachers, Kinki Central Hospital, Hyogo, Japan 3Region 5 of the California Cancer Registry, Desert Sierra Cancer Surveillance Program, Loma Linda, California 4Department of Surgery, School of Medicine, Loma Linda University, Loma Linda, California.
Abstract
BACKGROUND: Perioperative chemoradiotherapy is being used for the treatment of locally advanced rectal cancer to improve survival and reduce recurrence. Although several studies have prompted these changes, the survival benefits of additional chemoradiotherapy have not been adequately tested in a large-scale, population-based setting. OBJECTIVE: The purpose of this study was to evaluate survival differences between perioperative chemoradiotherapy and surgery alone for the treatment of rectal cancer. DESIGN: : This was a nonconcurrent cohort study of patients treated for rectal cancer stages II and III between 1994 and 2009. SETTING: The study was conducted through the California Cancer Registry. PATIENTS: Eligible patients were those with rectal cancer stage II or III who received either radical surgery alone (N = 2988) or perioperative chemoradiotherapy (N = 8852) during the study period. MAIN OUTCOME MEASURES: Cox proportional hazards regression was used to assess the risk of mortality associated with perioperative chemoradiotherapy versus surgery alone, adjusting for age, sex, race/ethnicity, socioeconomic status, tumor stage, month/year of surgery, and hospital factors. RESULTS: In multivariable binomial log-linear regression, the adjusted prevalence ratio (PR) for receiving perioperative chemoradiotherapy was lower among patients in the older age groups, especially among those ≥75 years of age (PR = 0.52 [95% CI, 0.49-0.55]), and increased monotonically from lowest (PR = 0.92 [95% CI, 0.89-0.95]) to highest socioeconomic status group (referent). Multivariable Cox proportional hazards regression analysis, adjusting for demographic factors, tumor stage, and hospital identification number, showed that perioperative chemoradiotherapy, relative to surgery alone, was associated with lower mortality during the entire study period, with survival benefit increasing over time (1994-1997: HR = 0.76 [95% CI, 0.66-0.88]; 1998-2001: HR = 0.71 [95% CI, 0.64-0.79]; 2002-2005: HR = 0.63 [95% CI, 0.55-0.71]; 2006-2008: HR = 0.47 [95% CI, 0.39-0.56]). LIMITATIONS: No information was available on comorbidities or specific surgeon factors, which could contribute to survival differences. CONCLUSIONS: Perioperative chemoradiotherapy, compared with surgery alone, was associated with significantly improved survival during the entire study period, with increasing benefit among those treated during the latter years of our studied time period. (see Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A120).
BACKGROUND: Perioperative chemoradiotherapy is being used for the treatment of locally advanced rectal cancer to improve survival and reduce recurrence. Although several studies have prompted these changes, the survival benefits of additional chemoradiotherapy have not been adequately tested in a large-scale, population-based setting. OBJECTIVE: The purpose of this study was to evaluate survival differences between perioperative chemoradiotherapy and surgery alone for the treatment of rectal cancer. DESIGN: : This was a nonconcurrent cohort study of patients treated for rectal cancer stages II and III between 1994 and 2009. SETTING: The study was conducted through the California Cancer Registry. PATIENTS: Eligible patients were those with rectal cancer stage II or III who received either radical surgery alone (N = 2988) or perioperative chemoradiotherapy (N = 8852) during the study period. MAIN OUTCOME MEASURES: Cox proportional hazards regression was used to assess the risk of mortality associated with perioperative chemoradiotherapy versus surgery alone, adjusting for age, sex, race/ethnicity, socioeconomic status, tumor stage, month/year of surgery, and hospital factors. RESULTS: In multivariable binomial log-linear regression, the adjusted prevalence ratio (PR) for receiving perioperative chemoradiotherapy was lower among patients in the older age groups, especially among those ≥75 years of age (PR = 0.52 [95% CI, 0.49-0.55]), and increased monotonically from lowest (PR = 0.92 [95% CI, 0.89-0.95]) to highest socioeconomic status group (referent). Multivariable Cox proportional hazards regression analysis, adjusting for demographic factors, tumor stage, and hospital identification number, showed that perioperative chemoradiotherapy, relative to surgery alone, was associated with lower mortality during the entire study period, with survival benefit increasing over time (1994-1997: HR = 0.76 [95% CI, 0.66-0.88]; 1998-2001: HR = 0.71 [95% CI, 0.64-0.79]; 2002-2005: HR = 0.63 [95% CI, 0.55-0.71]; 2006-2008: HR = 0.47 [95% CI, 0.39-0.56]). LIMITATIONS: No information was available on comorbidities or specific surgeon factors, which could contribute to survival differences. CONCLUSIONS: Perioperative chemoradiotherapy, compared with surgery alone, was associated with significantly improved survival during the entire study period, with increasing benefit among those treated during the latter years of our studied time period. (see Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A120).