Primary Testicular Lymphoma: Oncologic Outcomes and Treatment Patterns
Primary Testicular Lymphoma (PTL) is the most common testicular cancer in older men. Little documentation of this important disease is available in the urologic literature. Since PTL is not represented in germ cell (GCT) databases, epidemiology can only be ascertained by examination of lymphoma databases. As the US population ages, this disease presents more commonly to urologists. We evaluate the epidemiology of PTL and compare the oncological outcomes and treatment patterns of PTL and GCT.
We examined 2 large databases from the National Cancer Database (NCDB) 2004-13. Using NCDB&[prime]s Lymphoma DB diagnosis of extra nodal lymphoma (N=133,172) we compared the frequency of PTL (N=2250) to GCT from the germ cell DB (N=45078). Demographic information (DI), treatment options (TO), and histopathological features were obtained. Kaplan-Meier (KM) survival plots were used to examine OS at 5 & 8 yrs post diagnosis. Classical Cox proportional hazards models assessed the effect of DI and TO on OS in PTL.
2,096 PTL patients post orchiectomy were analyzed. PTL represents the most frequent testicular malignancy in men >65 (Fig 1). The Charlson Comorbidity Index (CCI) 0, 1 and 2+ was 79%, 17% and 4% for PTL and 94%, 5% and 1 % for GCT. Analysis of the TO of our PTL cohort showed that 825 (39%) men underwent chemotherapy (ChT); 68 (4%) radiotherapy (RT); 732 (35%) RT + ChT; 471 (22%) no further treatment after orchiectomy. Cox regression showed increased CCI scores were significantly associated with mortality risk in PTL at 5 years (CCI 1 with HR 1.29 [1.04-1.61; p = 0.017], CCI ≥2 with HR 2.17 [1.51-3.11; p = 0.001]) and 8 years (CCI 1 with HR 1.31 [1.07-1.62; p = 0.007], CCI ≥2 with HR 2.08 [1.44-3; p = 0.001]). KM survival analysis showed that 5 & 8 year OS was 65% and 61% respectively for PTL vs. 96% at 5 & 8 years for GCT.
NCDB data includes >70% of newly diagnosed US malignancies, allowing us to analyze the largest cohort for PTL to date. PTL becomes more prevalent >65 yrs. Higher CCI adversely impacted OS. Further, we have shown that only 1 in 3 PTL patients received appropriate treatment with ChT+RT following orchiectomy, a significant underutilization of National Comprehensive Cancer Network (NCCN) guidelines (Version 2.2015), underlining the importance of following NCCN guidelines in PTL.