1. Various Aspects Of The
Tumor Response To
Radiotherapy In Rectal
Cancer
Authors: Prof. Dr. E. Bratucu
Sinziana Ionescu
Bucharest Oncology Institute
2. Purpose And Goals
As rectal tumors answer in different grades to
radiotherapy, we aim at evaluating –right from the
moment of the biopsy- the capacity of the tumor to
react or not to this treatment option
We find the immunohistochemical evaluation of the
tumor to be of crucial importance and we highly
recommend it to be done on the biopsy before
radiotherapy
3. Group Of Patients Studied
Patient distribution by sex was equal
between the two sexes, with 26 patients
each.
We examined tissue samples using
paraffin blocks from 52 patients.
The examinations were done
comparatively, both:
-before radiotherapy
(tissues from diagnostic biopsy), as
- after radiotherapy
(tissues from abdomino-perineal
resection).
The patients had received treatment in the following units:
Bucharest Oncology Institute, Coltea, Fundeni and Colentina Hospital
The parametres studied were:
A. histological and
B. immunohistochemical
4. A.Histological parameters studied
Cell type
distribution
p=0.96
Distribution of the
desmoplastic
reaction p=0.218
Distribution of
atypias
p= 0.910
Distribution of the
colloid type*
p=0,001
*
The only morphological parameter with statistical meaning, using the χ test with
corresponding p value
5. Cellular type
Cell shape and architecture are determined by
interactions between the cell and the extracellular
matrix and have profound effects on cellular behavior,
chromatin condensation, and tumor cell resistance to
radiotherapy and chemotherapy.
Transformation from cylindrical to cubic: oncocytic
change in this particular clinical context occurs as a
reflection of cytotoxic damage or cellular hypoxia
induced by chemo-radiation resulting in degeneration
of the cell and of the oncocytic phenotype.
6. Cell type distribution before and after radiotherapy was predominantly cylindrical before
radiotherapy(RIB) and cubic after radiotherapy (RIC)
Cylindrical Cubic
RIB 45 7
RIC 8 44
0
10
20
30
40
50
Cell type distribu on before and a er
radiotherapy
RIB
RIC
7. Desmoplastic reaction
Desmoplastic reaction has been defined as being
associated with some tumors and is characterized by
the pervasive growth of dense fibrous tissue around the
tumor. This reaction makes it difficult to distinguish
between spiculation in the perirectal fat caused by
fibrosis alone from that caused by fibrous tissue that
contains tumor cells. Cancer associated with a reactive
stroma is typically diagnostic of poor prognosis.
8. The distribution of desmoplastic reaction before and after radiotherapy: if before
radiotherapy the predominant demoplastic reactions were of grades 1 and 2, after
radiotherapy the predominant desmoplastic reaction becomes 1.
9. Cellular atypia
Cellular atypias have been studied in the context of
their association with increased severity of the
neoplasm
The individual tumor cells in treated rectal cancer may
show marked nuclear atypias .Marked cytoplasmic
eosinophilia, often in association with nuclear atypias is
the most commonly seen type of cytological alteration
in tumors after radiation.
10. The variation of the distribution of atypia before and after radiotherapy has kept the
same type 2 as the main type of atypia
11. Colloid type
Mucinous adenocarcinoma is characterised by
abundant extracellular mucin produced by tumour cells.
By definition, a 50% or greater mucinous component is
required for the designation of mucinous colorectal
carcinoma . The prognostic significance of mucinous
carcinoma is controversial, many authors associating it
with a poor prognosis in which regards
chemoradiotherapy.
15. The variation in the distribution of the colloid response
before and after radiotherapy changes consistently
from dominant 0 to dominant 1.
16. Colloid type
The increase of the colloid type from 0 to 1 would lead us
towards the assumption that radiotherapy either induced or
aggravated the expression of the colloid type
The literature used as reference showed that those cancers
which appeared to have been induced by radiotherapy had
mostly colloid features, therefore in a patient which was
irradiated for prostate cancer , we could estimate weather the
neoplasm appeared d’en blais or consequently to
radiotherapy
17. I.MARKERS OF STATISTICAL IMPORTANCE
EGFR in the
tumor
(p=0.00045)
EGFR in the
normal
epithelium
(p=0.0017)
VEGF in the
tumor
(p=0,0132)
VEGF in the
tumor
stroma
(p=0,030).
P53
(p=0,044)
B.Immunohistochemical parameters studied
II.MARKERS WITHOUT STATISTICAL IMPORTANCE, WITH OBSERVATION-ONLY
SIGNIFICANCE
CK 7
P=0.6404
CK 20
P=0.278
E-cadherin
P=0.368
Vimentin
P value was not
calculated, as all
the tissues had the
0 value.
CEA
BCL 2 CYCLIN D1
18. EGFR si VEGF-part 1
EGFR (epidermal growth factor receptor) exists on the cell
surface as a transmembrane glycoprotein , a member of the
protein kinase superfamily. This protein is a receptor for
members of the epidermal growth factor family.and is
activated by binding of its specific ligands, including
epidermal growth factor and transforming growth factor α
(TGFα). Mutations, amplifications or misregulations of EGFR
or family members are implicated in about 30% of all
epithelial cancers. The identification of EGFR as an
oncogene has led to the development of anticancer
therapeutics directed against EGFR, including gefitinib and
erlotinib for lung cancer, and cetuximab for colon cancer.
19. EGFR si VEGF part 2
Current findings have demonstrated that alterations in
tumor stromal pathways, including the EGFR pathways,
are associated with, and may contribute to, resistance to
VEGF inhibitors and that targeting these pathways may
improve therapeutic efficacy. Understanding stromal
signaling may be critical for developing biomarkers for
angiogenesis inhibitors and improving combination
regimens and this is the reason why we chose to study
EGFR and VEGF both at the level of the tumor and at the
level of the stroma and the grades are given according to
appreciation of two independent examining doctors
regarding the amount of EGFR and VEGF in the tissue
studied.
20. The variation with radiotherapy of EGFR in the tumor: the tissues before radiotherapy
had similar numbers of grades 1 and 2 and after radiotherapy grade 2 was the main grade
found among the tissues examined
EGFR in the tumor increased by a mean of 1 unit
21. EGFR in the normal epithelium before and
after radiotherapy
0
5
10
15
20
25
30
35
0
1
2
3
0 1 2 3
RIC 15 19 12 6
RIB 17 7 10 18
EGFR in the normal epithelium before and after
radiotherapy
RIC
RIB
25. Observation and specification of EGFR
examination
EGFR in the normal stroma increases its expression in
the smooth muscle and nervous fibres normal tissues
which appear to be modified by irradiation with a χ of
0,0002 and a corresponding p value of 0.02.
These results (increased EGFR in the tumor, in the
normal epithelium and in the normal stroma) may have
clinical impact in a negative way, as patients with
increased postradiotherapy EGFR had decreased
overall survival and decreased disease free interval
26. Comparison between VEGF in the tissues
before(RIB) and after radiotherapy(RIC)
RIB
RIC in the normal mucosa
RIC in the tumor
27. VEGF in the tumor before and after radiotherapy
28. VEGF in the tumor stroma before and after radiotherapy
RIB
RIC
0
5
10
15
20
25
GRADE 0 GRADE 1 GRADE 2 GRADE 3
RIB 12 10 11 19
RIC 10 22 12 8
VEGF in the tumor stroma
RIB
RIC
29. Comparison between the VEGF values before and after radiotherapy at the tumor
level(first pile to the left of the viewer) and at the level of the tumor stroma (pile at the
right of the viewer).
RIB
0
20
40
GRADE 0
GRADE 1
GRADE 2
GRADE 3
GRADE 0
GRADE 1
GRADE 2
GRADE 3
Varia on with radiotherapy of the
values of the VEGF in the tumor and
in the tumor stroma
RIB
RIC
30. Observation
The increase of VEGF with radiotherapy in the tumor
and in the tumor stroma was demonstrated also by
other studies, those indicating the correlation between
the increase in VEGF and: larger lymph node invasion,
larger expansion of the tumor growth, bigger rate of
radiation proctitis
31. Out of 52 cases, in 4 , we have observed CEA becoming negative, a fact which could
imply that in irradiated rectal tumors, a loss of the CEA expression would mislead us
between a tumor which does not express it and a tumor that has disappeared with
radiotherapy (we may mistake a change in tumor biology by a maximum tumor
regression grade)
CYCLIN D1 has a trend in becoming positive with radiotherapy. Cyclins regulate the
progression of the cell through the cell cycle from G1 to S phase
BCL2 shows a cell which is not able to enter an apoptosis. The expression of BCL-2 is
lost in moderately and weakly differentiated tumors and kept in well differentiated ones.
There is a vague increasing trend with radiotherapy from which we infer that
radiotherapy would lead to a change in tumor biology. The integrity of the mitochondrial
outer membrane is regulated by pro-apoptotic and anti-apoptotic members of the BCL2
family of proteins
Observations regarding the parameters without statistical significance
32. Conclusions part 1
The following morphological factors studied in our batch did not
present with statistical significance so we could neither
demonstrate nor quantify the influence of radiotherapy on them:
cell type, desmoplastic reaction, atypias. On the other hand, the
colloid type suffered a marked change with radiotherapy
becoming in the majority of the cases from 0- 1 .
Other markers of statistical significance were EGFR at the
tumor level, EGFR in the tumor stroma, EGFR in the normal
epithelium and they all increased. Moreover, EGFR increased
in expression in the smooth muscle fibers and nervous fibres
demonstrating the involvement of the normal stroma in the
response to radiotherapy . Another marker which was modified
with radiotherapy was VEGF in the tumor and VEGF in the
tumor stroma.
33. Conclusions -part 2
The results are similar in trend to those in the
scientific literature consulted in which concerns EGFR
and VEGF.
Our study has a rather individual and original statement
in comparison to those consulted using the pubmed
index, in which concerns the stromal reaction to
radiotherapy which could be more aggressive and
statistically important than the reaction of the tumor
tissues
34. Limits and Perspectives
The most important limit of our study stands in the
small number of cases , mostly in the situations in
which we confronted with the problem of insufficient
tissues
In which regards future improvements, apart from
extending the number of cases for the markers
studied , it would be interesting to find out their
correlation between overall survival and the disease
free interval in those patients.
35. We thank Conferee Dr S.Zurac and Professor Dr. F.Staniceanu, from the pathology
department of the Colentina Clinical Hospital for their special collaboration in our study
"ACKNOWLEDGEMENT: This paper is supported by the Sectoral Operational
Programme Human Resources Development (SOP HRD) 2007-2013, financed
from the European Social Fund and by the Romanian Government under the
contract number POSDRU/107/1.5/S/82839",
