Evaluation of perioperative therapy for stage II and III rectal cancer in California, 1994-2009.

Background:  Surgical treatment of stage II and III rectal cancer changed little during the past two decades, while ancillary therapies have undergone two evolutionary changes. We sought to evaluate changes in chemoradiation (chemoRT) practices for patients receiving radical operations for stage II and III rectal cancer in California, 1994-2009.  Methods:  We extracted age, sex, race/ethnicity (R/E), socioeconomic status (SES) (demographic variables) and chemoRT variables for stage II and III rectal cancer cases in California. We used unconditional logistic regression to compute independent odds ratios of receiving preoperative chemoRT (PreOP Tx) to postoperative chemoRT (PostOP Tx) during Early (1994-1999), Middle (2000-2003), and Late (2004-2009) time-periods using the late time-period as the referent group.  Results:  Logistic regression analyses assessing time-period and demographic variables reveal trends and odds ratios with 95% confidence intervals (OR; CI) for chemoRT variables. Our findings showed a stepwise increase in the odds of PreOP Tx to PostOP Tx across Early, Middle, to Late time-periods (OR Early/Late =0.11; 0.10, 0.13, OR Middle/Late =0.36; 0.32, 0.40). Age <40 and 40-49, independently predicted higher odds of PreOP Tx than PostOP Tx compared to age 50-74, while the findings for subjects age 75+ were similar to those seen in the age 50-74 group (OR <40/50-74 =1.63; 1.30, 2.05, OR 40-49/50-74 =1.18; 1.03, 1.36, OR 75+/50-74 =1.04; 0.90, 1.18). Females showed lower odds of PreOP Tx to PostOP Tx than males (OR Female/Male =0.85; 0.77, 0.93). Odds of PreOP Tx to PostOP Tx were significantly lower among Asian/Other (A/O) and Hispanic relative to Non-Hispanic White (NHW), while findings were similar to NHW for Non-Hispanic Black (NHB) (OR A/O/NHW =0.85; 0.74, 0.98, OR Hispanic/NHW =0.84; 0.73, 0.96, OR NHB/NHW =0.92; 0.73, 1.15). SES did not predict odds of PreOP Tx versus PostOP Tx.  Conclusions: These findings depict independent increases in PreOP Tx across the three time-periods among stage II and III rectal cancer patients receiving radical operations. Further analyses will evaluate survival characteristics predicted by changes in perioperative therapies for stage II and III rectal cancer patients.