Lymphoedema remains a significant clinical problem, with 1:5 women in this sample developing the condition following treatment for breast cancer. Risk factors are identified in the development of lymphoedema that should be taken into account in clinical practice.

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258 Background: We reported initial findings on the phenotypic differences between de novo versus primary progressive metastatic prostate cancer (Finianos et al., ASCO GU; abstr 285). We sought to determine the differences in the phenotypic characteristics of these 2 cohorts of patients and update the data with overall survival and patterns of response to androgen deprivation therapy (ADT) in patients presenting with de novo versus primary progressive prostate cancer. Methods: A retrospective chart review in a single-institution center for a period of 2 years was undertaken. Phenotypic characteristics included age at diagnosis, race, overall survival, treatment patterns, and response to ADT. Analysis was by t-test, Mann-Whitney U test, and Fisher’s Exact test. Results: A total of 90 patients were included in this cohort with de novo, dn (n = 38) and primary progressive, pp (n = 52) patients. There were no significant differences between the 2 cohorts with regard to the median age at diagnosis (dn = 66, pp = 61, p = 0.11), alkaline phosphatase level (dn = 135.5, pp = 86, p = 0.27), BMI (dn = 28.47, pp = 27, p = 0.78), creatinine (dn = 1.02, pp = 0.99, p = 0.34), LDH (dn = 188, pp = 166, p = 0.34), and testosterone on metastasis (dn = 276, pp = 31, p = 0.16). However, de novo cancers were diagnosed with higher mean gleason scores (dn = 8.36, pp = 7.7, p = 0.004), had higher median PSA upon diagnosis (dn = 63.1, pp = 8.8, p < .0001) and higher PSA on metastasis (dn = 61.7, pp = 12.5, p = .0002), and had a statistically significant decreased duration of hormone sensitivity (dn = 642 days, pp = 1783 days, p = < .0001). Patients with d e novo cancers also had a shorter median survival than primary progressive cancers (dn = 2257 days, pp = 4217 days, p = 0.02). Conclusions: Patients who present with de novo metastatic prostate cancer appear to develop early castration resistance and have worse overall survival than those who present with primary progressive disease. We are exploring the molecular differences in terms of androgen receptor expression as a potential etiology for development of early castration resistance.