NATURAL KILLER CELLS IN RECTAL CANCERS TREATED WITH NEOADJUVANT CHEMORADIOTHERAPY   — ASN Events
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NATURAL KILLER CELLS IN RECTAL CANCERS TREATED WITH NEOADJUVANT CHEMORADIOTHERAPY   (#10)

Stephanie H Lim 1 2 3 , Wei Chua 1 2 , Christina Cheng 4 , Joseph Descallar 2 3 , Weng Ng 1 2 , Michael Solomon 5 6 , Paul de Souza 1 2 3 , Joo S Shin 2 4 7 , Soon S Lee 2 3 4 6 7
  1. Department of Medical Oncology, Liverpool Hospital, NSW, Australia
  2. Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
  3. University of New South Wales, NSW, Australia
  4. Discipline of Pathology and Molecular Medicine Research Group, University of Western Sydney, Liverpool, Australia
  5. Department of Colorectal Surgery, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
  6. University of Sydney, NSW, Australia
  7. Department of Anatomical Pathology, Liverpool Hospital, NSW, Australia

BACKGROUND

Natural killer cells (NKC) appear important in rectal tumour control. The relationship between NKC with neoadjuvant chemoradiotherapy and clinical outcomes is unclear.  

AIMS

We wished to investigate total T-lymphocytes (CD3+) and NKC (CD56 and CD57) in normal and rectal tumour tissues pre- and post-chemoradiotherapy, and relationship to tumour regression grade (TRG), 3-year disease-free survival (DFS) and pathological stage.

METHODS

We examined samples from 52 patients with locally advanced rectal cancer patients, treated with pre-operative short-course or long-course radiotherapy with concurrent 5-fluorouracil, followed by surgery.  Tissue microarrays, from colonoscopic biopsies (pre-treatment), resection specimens (post-treatment) and normal tissue, were immunostained for CD3, CD56 and CD57.  Paired t-tests were used to analyse differences in these counts between pre-treatment, post-treatment and normal tissue (Bonferroni adjusted significance p = 0.025). Logistic and ordinal regression were used to correlate CD3 and NKC with TRG and stage respectively. Cox regression was used to analyse DFS.

RESULTS

The median patient age was 63 years. 19 patients received short-course and 33 long-course treatments. TRG in the resected tumours were (TRG=n) (1=1, 2=8, 3=20, 4=19, 5=4).  The median 3-year DFS was 2.8 years.

In pre-treatment tumour biopsies, NKC count was significantly decreased compared to normal tissue (p = 0.007). There were no differences in tumour NKC counts pre- and post-treatment.  There was no correlation of NKC count in pre- and post-treatment samples with stage or DFS.  There was a trend towards significance of higher post-treatment NKC count with higher tumour regression (p = 0.038).  CD3 was increased in post-treatment samples (p = 0.025). 

CONCLUSION

NKC were reduced in rectal cancers versus normal tissue and their presence may be important in tumour regression. CD3 lymphocyte counts were increased post-chemoradiotherapy, suggesting a possible role for individual T-cell subsets; this warrants further studies.