Prevalence and distribution pattern of nodal metastases in advanced ovarian cancer

Prognostic significance and risk factors for pelvic and para-aortic lymph node metastasis in type I and type II ovarian cancer: a large population-based database analysis

BACKGROUND

To compare the prognosis of lymphatic metastasis in type I and type II epithelial ovarian cancer (OC) and to identify the risk factors for pelvic lymph node metastases (PLNs) and para-aortic lymph node metastases (PALNs).

METHODS

Patients diagnosed with epithelial OC were collected from the Surveillance, Epidemiology, and End Results (SEER) database. Overall survival (OS) and cancer-specific survival (CSS) were estimated. The Cox proportional hazards regression model was used to identify independent predictors of survival.

RESULTS

A total of 11,275 patients with OC were enrolled, including 31.2% with type I and 68.8% with type II. Type II and high tumour stage were risk factors for lymph node involvement (p < 0.05). The overall rate of lymph node metastasis in type I was 11.8%, and that in type II was 36.7%. In the type I group, the lymph node metastasis rates in stages T1, T2, T3 and T_XM₁ were 3.2%, 14.5%, 40.4% and 50.0%, respectively. In the type II group, these rates were 6.4%, 20.4%, 54.1% and 61.1%, respectively. Age and tumour size had little effect on lymph node metastasis, and grade 3 was not always a risk factor. For the type I group, the 10-year CSS rates of LN(-), PLN( +), PALN( +), and PLN + PALN( +) were 80.6%, 46.6%, 36.3%, and 32.3%, respectively. The prognosis of PLN ( +) was better than that of PALN ( +) in the type I group (p > 0.05). For the type II group, the 10-year CSS rates of LN(-), PLN( +), PALN( +), and PLN + PALN( +) were 55.6%, 18.5%, 25.7%, and 18.2%, respectively. PALN ( +) had a significantly better prognosis than PLN ( +) in the type II group (p < 0.05).

CONCLUSIONS

The clinical characteristics and prognoses of patients with type I and type II OC differed greatly. Patients with type II and higher tumour stages had poorer prognoses. Type I with PALN metastasis and type II with PLN metastasis indicated a worse prognosis. Patients with stage TI did not require lymph node dissection, especially in the type I group.

Predictive factors of lymph node metastasis and pattern of repartition in patients with epithelial ovarian cancer

Aim: To determine the rate, repartition and risk factors of lymph node (LN) metastasis in patients with epithelial ovarian cancer. Methods: We reviewed retrospectively the pathological and clinical data of 184 patients with epithelial ovarian cancer at a tertiary care center in Beirut, Lebanon. Results: 88% of patients received a pelvic and para-aortic lymphadenectomy. 70% of patients presented LN metastases at both pelvic and para-aortic levels, while isolated pelvic or para-aortic LN metastases were seen in 16 and 14% of cases, respectively. In a univariate analysis, the rate of positive LNs was higher in patients with serous histology (65 vs 33%; p < 0.001), high-grade tumors (68 vs 26%; p < 0.001), bilateral adnexal involvement (74 vs 27%; p < 0.001), advanced clinical stage (p < 0.001), interval debulking surgery (63.2 vs 36.8%; p = 0.003) and positive peritoneal cytology (79 vs 26%; p < 0.001). In a multivariate analysis, the rate of LN involvement was significantly higher in patients with higher grade, advanced clinical stage and positive peritoneal cytology. Conclusion: Serous histology, grade 3 tumors, positive peritoneal cytology, advanced clinical stage, interval surgery and bilateral adnexal involvement can predict LN metastasis in patients with epithelial ovarian cancer.

Inflammatory state of lymphatic vessels and miRNA profiles associated with relapse in ovarian cancer patients

Lymphogenic spread is associated with poor prognosis in epithelial ovarian cancer (EOC), yet little is known regarding roles of non-peri-tumoural lymphatic vessels (LVs) outside the tumour microenvironment that may impact relapse. The aim of this feasibility study was to assess whether inflammatory status of the LVs and/or changes in the miRNA profile of the LVs have potential prognostic and predictive value for overall outcome and risk of relapse. Samples of macroscopically normal human lymph LVs (n = 10) were isolated from the external iliac vessels draining the pelvic region of patients undergoing debulking surgery. This was followed by quantification of the inflammatory state (low, medium and high) and presence of cancer-infiltration of each LV using immunohistochemistry. LV miRNA expression profiling was also performed, and analysed in the context of high versus low inflammation, and cancer-infiltrated versus non-cancer-infiltrated. Results were correlated with clinical outcome data including relapse with an average follow-up time of 13.3 months. The presence of a high degree of inflammation correlated significantly with patient relapse (p = 0.033). Cancer-infiltrated LVs showed a moderate but non-significant association with relapse (p = 0.07). Differential miRNA profiles were identified in cancer-infiltrated LVs and those with high versus low inflammation. In particular, several members of the let-7 family were consistently down-regulated in highly inflamed LVs (>1.8-fold, p<0.05) compared to the less inflamed ones. Down-regulation of the let-7 family appears to be associated with inflammation, but whether inflammation contributes to or is an effect of cancer-infiltration requires further investigation.

The passive biomechanics of human pelvic collecting lymphatic vessels

The lymphatic system has a major significance in the metastatic pathways in women's cancers. Lymphatic pumping depends on both extrinsic and intrinsic mechanisms, and the mechanical behavior of lymphatic vessels regulates the function of the system. However, data on the mechanical properties and function of human lymphatics are lacking. Our aim is to characterize, for the first time, the passive biomechanical behavior of human collecting lymphatic vessels removed at pelvic lymph node dissection during primary debulking surgeries for epithelial ovarian cancer. Isolated vessels were cannulated and then pressurized at varying levels of applied axial stretch in a calcium-free Krebs buffer. Pressurized vessels were then imaged using multi-photon microscopy for collagen-elastin structural composition and fiber orientation. Both pressure-diameter and force-elongation responses were highly nonlinear, and axial stretching of the vessel served to decrease diameter at constant pressure. Pressure-diameter behavior for the human vessels is very similar to data from rat mesenteric vessels, though the human vessels were approximately 10× larger than those from rats. Multiphoton microscopy revealed the vessels to be composed of an inner layer of elastin with an outer layer of aligned collagen fibers. This is the first study that successfully described the passive biomechanical response and composition of human lymphatic vessels in patients with ovarian cancer. Future work should expand on this knowledge base with investigations of vessels from other anatomical locations, contractile behavior, and the implications on metastatic cell transport.