Schymura et al. BMC Cancer 2010, 10:152 http://www.biomedcentral.com/1471-2407/10/152 Page 10 of 15 Table 3: Percentage (%) distributions and odds ratios for receipt of conservative therapy (n = 3,328). (Continued) PSA value 0-4 >4-10 >10-20 >20-50 50+ Unknown 2-4 5-7 8-10 Unknown Gleason score Comorbidity score 0 1 2+ 27.59 20.15 29.01 45.38 52.25 49.89 45.17 25.05 34.26 48.58 26.91 39.00 54.78 1.00 0.66 1.07 2.18 2.87 2.61 1.00 0.41 0.63 1.15 1.00 1.74 3.29 (referent) (0.50 - 0.88) (0.79 - 1.47) (1.53 - 3.12) (1.83 - 4.53) (1.91 - 3.60) (referent) (0.32 - 0.51) (0.46 - 0.87) (0.88 - 1.61) (referent) (1.41 - 2.14) (2.26 - 4.81) 1.00 0.69 0.80 1.41 1.73 1.64 1.00 0.45 0.49 0.75 1.00 1.44 2.59 (referent) (0.50 - 0.97) (0.56 - 1.15) (0.93 - 2.15) (1.02 - 2.94) (1.12 - 2.41) (referent) (0.34 - 0.59) (0.33 - 0.72) (0.50 - 1.13) (referent) (1.12 - 1.86) (1.67 - 4.03) 1: OR = odds ratio; CI = confidence interval. 2: Adjusted for factors shown in the table. ited to external beam radiation, and for watchful waiting compared to hormone therapy, these differences were not statistically significant after adjusting for other factors. Our findings are generally consistent with those from other observational studies, which have shown an overall survival advantage for definitive treatment versus watch- ful waiting [37] and no overall survival advantage for hor- mone therapy compared to watchful waiting [38]. A recent trial of immediate versus deferred androgen depri- vation, which our study did not examine, found a modest increase in overall survival for immediate androgen deprivation [39]. In observational studies such as ours, caution must be exercised in attributing survival differ- ences to treatment received since healthier patients are more likely to be treated aggressively and residual con- founding cannot be discounted [40,41]. Our study was subject to several limitations. Because of our reliance on medical records, we were not able to dis- tinguish between actual watchful waiting and surveil- lance, the latter being an active management process where "curative" treatment may be applied if progression is noted. This may explain why we observed somewhat better survival for watchful waiting than for hormone therapy. Significant advances have been made in the treatment of prostate cancer since 1997. Radical prostatectomy is increasingly being performed laparoscopically. Three dimensional conformal radiotherapy (3D-CRT), which had been the accepted standard of external beam therapy until the past 5-7 years, is being supplanted by intensity modulated radiation therapy and stereotactic body radio- therapy, and to a lesser extent, proton beam radiotherapy. However, although practice patterns may have changed, understanding the factors associated with choice of defi- nite treatment versus conservative management remains relevant. Another limitation is lack of information on patient preferences, their attitudes toward the medical system as well as on the patient and physician decision-making pro- cess. Prostate cancer treatment selection is influenced by external recommendations, concerns about effects of treatment on quality of life, characteristics of the treat- ment itself, economic and logistic considerations, as well as by personal perceptions and values [42,43]. In one study prostate cancer patients reported that the physician was the most important factor influencing their treat- ment decision [44]. Other studies found that treatment selection for prostate cancer was related to the treatment options that were discussed [11], the information patients received [45], and the extent to which patients were involved in the decision-making process [46]. Patient involvement in the choice of treatment is particularly important in early stage prostate cancer because the vari- ous treatment regimens often involve significant side effects [47-49] that impact quality of life and patient satis- faction with treatment outcomes [50-52]. Although this study included samples from seven states and resulted in a fairly large sample size, results may not be generalizable to the entire country. Additionally, the study did not over-sample minorities. Therefore, the