Oops, you're using an old version of your browser so some of the features on this page may not be displaying properly.

MINIMAL Requirements: Google Chrome 24+Mozilla Firefox 20+Internet Explorer 11Opera 15–18Apple Safari 7SeaMonkey 2.15-2.23

Poster display session

2418 - Immunological features of resected tumor after neoadjuvant chemotherapy (NAC) and chemoradiotherapy (CRT) become the superior prediction markers for recurrence in rectal cancer.

Date

09 Sep 2017

Session

Poster display session

Presenters

Ken Imaizumi

Citation

Annals of Oncology (2017) 28 (suppl_5): v158-v208. 10.1093/annonc/mdx393

Authors

K. Imaizumi1, T. Suzuki2, M. Shimomura2, Y. Tsukada1, T. Sasaki1, Y. Nishizawa1, M. Kojima3, M. Ito1, T. Nakatsura2

Author affiliations

  • 1 Colorectal Surgery, national cancer center hospital east, 277-0882 - Kashiwa/JP
  • 2 Cancer Immunotherapy, Exploratory Oncology Research & Clinical Trial Center, national cancer center, 277-0882 - Kashiwa/JP
  • 3 Pathology, national cancer center hospital east, 277-0882 - Kashiwa/JP
More

Resources

Abstract 2418

Background

Although CRT is the standard neoadjuvant therapy for local advanced rectal cancer (RC), benefits of NAC have also been reported recently. In this study, we investigate whether the tumor microenvironment is related to local therapeutic effects and recurrence free survival (RFS) after neoadjuvant therapy, and explore the role of the anti-tumor immune response in cancer treatment.

Methods

200 RC patients were enrolled and categorized into three groups according to pretreatment: CRT (n = 48, 5-Fluorouracil or Capecitabine + Radiation), NAC (n = 51, FOLFOX), Surgery alone (n = 101). The infiltration and status of immune cells were assessed by multiplex fluorescence immunohistochemically analysis.

Results

The growth of residual tumor cells after treatment was evaluated using Ki67 expression. Compared with the surgery group, CRT, but not NAC, significantly decreased the percentage of Ki67high cells in cytokeratin positive cells. However, the percentage of Ki67high tumor cells is comparable between all tumor regression grade (TRG) groups. Assessing the immunological features of tumor tissues, we found that the infiltration of T cells into tumors is significantly higher in TRG 1 patients than in patients with TRG 2, 3, and those treated with surgery alone. The percentage of tumor infiltration in Ki67high population of CD4 and CD8 T cells is more prominent, suggesting that aggressive infiltration of T cells might be involved in the treatment effect of neoadjuvant therapies. Notably, in the NAC group, patients with high accumulation of Ki67high CD8 T cells in tumor and stroma tissue experienced long term RFS, compared with patients with low accumulation of Ki67high CD8 T cells. On the other hand, after neoadjuvant therapy with CRT, patients with high accumulation of both CD8 and Ki67high CD4 T cells in tumor achieved long term RFS.

Conclusions

Our results suggested that CRT and NAC had different effects on the tumor microenvironment. The densities of Ki67high CD8 T cells in tumors could be a strong inhibitor of recurrence for RC after NAC. In the case of CRT, the densities of CD8 T cells and Ki67high CD4 T cells in tumors could inhibit recurrence.

Clinical trial identification

Legal entity responsible for the study

National Cancer Center Hospital East

Funding

National Cancer Center Research and Development Fund (28-A-8)

Disclosure

All authors have declared no conflicts of interest.

This site uses cookies. Some of these cookies are essential, while others help us improve your experience by providing insights into how the site is being used.

For more detailed information on the cookies we use, please check our Privacy Policy.

Customise settings