Immunobiology of high-grade serous ovarian cancer: lessons for clinical translation

Treatment of high-grade serous ovarian cancer (HGSOC) remains challenging. Although HGSOC can potentially be responsive to immunotherapy owing to endogenous immunity at the molecular or T cell level, immunotherapy for this disease has fallen short of expectations to date. This Review proposes a working classification for HGSOC based on the presence or absence of intraepithelial T cells, and elaborates the putative mechanisms that give rise to such immunophenotypes. These differences might explain the failures of existing immunotherapies, and suggest that rational therapeutic approaches tailored to each immunophenotype might meet with improved success. In T cell-inflamed tumours, treatment could focus on mobilizing pre-existing immunity and strengthening the activation of T cells embedded in intraepithelial tumour myeloid niches. Conversely, in immune-excluded and immune-desert tumours, treatment could focus on restoring inflammation by reprogramming myeloid cells, stromal cells and vascular epithelial cells. Poly(ADP-ribose) polymerase (PARP) inhibitors, low-dose radiotherapy, epigenetic drugs and anti-angiogenesis therapy are among the tools available to restore T cell infiltration in HGSOC tumours and could be implemented in combination with vaccines and redirected T cells.

Regulatory Role of the Adipose Microenvironment on Ovarian Cancer Progression

Simple Summary

Adipocytes or fat cells are integral part of the ovarian tumor microenvironment. Secreted factors from adipocytes, as well as direct cell-to-cell interaction with ovarian cancer cells have been shown to directly support ovarian tumor progression. Elucidating the molecular pathways involved is crucial in the identification of relevant targets.

Abstract

The tumor microenvironment of ovarian cancer is the peritoneal cavity wherein adipose tissue is a major component. The role of the adipose tissue in support of ovarian cancer progression has been elucidated in several studies from the past decades. The adipocytes, in particular, are a major source of factors, which regulate all facets of ovarian cancer progression such as acquisition of chemoresistance, enhanced metastatic potential, and metabolic reprogramming. In this review, we summarize the relevant studies, which highlight the role of adipocytes in ovarian cancer progression and offer insights into unanswered questions and possible future directions of research.

Should Bevacizumab Be Continued After Progression on Bevacizumab in Recurrent Ovarian Cancer?

Objective

The optimal role of bevacizumab (Bev) in the treatment of ovarian cancer has not yet been established. Furthermore, it is unclear whether there is a benefit of Bev after progression on a Bev-containing regimen in ovarian cancer. The objective of this study was to compare response rates, progression-free survival (PFS), and overall survival between patients who were treated with chemotherapy and Bev after progression on Bev (BAB) versus patients who were treated with chemotherapy without Bev (CWOB).

Methods

We conducted a retrospective chart review of all patients who received treatment with Bev (with or without cytotoxic chemotherapy) for recurrent ovarian cancer at a single institution. Patients who received additional therapy after progression while on Bev were included.

Results

Forty-six patients were included (16 CWOB group and 30 BAB). The median number of previous chemotherapy regimens was 2.5 for CWOB compared with 4 for BAB (P= 0.11). Fifty-two percent of patients had an objective response to the first Bev regimen before progressing on Bev. Response rates for the regimen after progression on Bev were 19% (3/16) in the CWOB group and 23% (7/30) in the BAB group (P= 1). Twenty-five percent of the patients who responded to the first Bev regimen and 18% of those who did not respond to the first Bev regimen responded to the second Bev regimen (P= 0.72). The median PFS for patients in the CWOB group was 2.6 months (95% confidence interval [CI], 1.3–5 months), compared with 5.0 months (95% CI, 3.5–7.3 months) for patients in the BAB group (P= 0.01). Overall survival was similar, 9.4 months (95% CI, 5.0–12.0 months) for CWOB versus 8.6 months (95% CI, 5.8–15.5 months) for BAB (P= 0.19). One patient in the BAB group died of a bowel perforation.

Conclusions

In patients previously treated with Bev for recurrent ovarian cancer, the subsequent addition of Bev to cytotoxic chemotherapy increased the PFS compared with patients not receiving a second course of Bev, but did so without an impact on overall survival. The response to the first Bev regimen did not predict whether a patient would respond again to the next Bev regimen. Randomized, larger studies will have to be performed to confirm this observation.

A clinical experience of single agent bevacizumab in relapsing ovarian cancer

OBJECTIVE

The objective of this study is to report the efficacy and tolerance of single agent bevacizumab (BEVA) in relapsing ovarian cancer patients treated in a single institution outside a clinical trial.

METHODS

To receive single agent BEVA, patients must have to relapse after at least one previous line of chemotherapy and to not have clinical conditions associated with high risk of gastrointestinal perforation. Dose-intensity of BEVA was 2.5mg/kg/week.

RESULTS

37 previously treated patients (33 with platinum resistant disease) were included in this retrospective analysis. The median number of BEVA infusion by patient was 5 (range: 1-61). The most frequent adverse effect was arterial hypertension, observed in 23 patients (62%), including 11 with G3 (30%) and 1 with G4. No intestinal perforation was reported. Tumor response rate according to CA 125 level (GCIG criteria) was 37% (11 of 30 patients). The median PFS and OS were 4 (range: 1 to +56) and 16 (range: 1 to +65) months (ms), respectively. 12-ms PFS was 25% (95% CI: 11-39%). The PFS tended to be better in patients who experienced grade 3-4 arterial hypertension during the first month of treatment (median: 10ms) compared to patients who did not (median: 3ms) (HR: 0.49 (95% CI: 0.18-1.03), p=0.06 by log rank test).

CONCLUSION

Single agent BEVA could be a reasonable option with favorable therapeutic index in pretreated ovarian cancer patients who do not want to suffer the side effects of chemotherapy provided to exclude those with high risk of intestinal perforation and carefully monitor blood pressure.