583 / 1082
S567
ESTRO 36 2017
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Conclusion
Elderly HNSCC patients have worse survival outcomes in
relation to younger patients. Age is an ind ependent
prognostic factor for OS, mainly due to an increase in non-
cancer related mortality and comorbid diseases.
EP-1034 Significance of mutant p53 and Ki67 as
predictive biomarkers post Chemo-RT in locally
advanced HNSCC
P. Baskaran Shanmuga
1
, K. Periasamy
1
, S. Sharma
2
, G.K.
Singh
1
, K. Pratap
1
, P. Singh
2
, V. Yadav
1
, A.K. Mandal
2
,
K.T. Bhowmik
1
1
Safdarjung Hospital, Radiotherapy, New Delhi, India
2
Safdarjung Hospital, Pathology, New Delhi, India
Purpose or Objective
The heterogeneity in outcome following chemoradiation
(CRT) in locally advanced HNSCC has drawn the attention
of clinical researchers towards molecular markers. Despite
almost three decades of research the role of several
biomarkers remain uncertain. This study intended to
speculate the significance of expression of mutant p53 and
Ki67 in treatment response, locoregional control and
survival.
Material and Methods
This prospective observational study included 62 patients
with stage III-IV non- nasopharyngeal head and neck
squamous cell carcinoma of which 58 patients completed
CRT. Immunohistochemistry was done on the pre-
treatment biopsy specimens and the expression of mutant
p53 and Ki67 in the tumor were graded based on the
degree of nuclear staining as negative (0%), low (≤ 20%),
medium (>20% - <40%) and high (≥ 40%). For statistical
analysis, negative and low expressions were categorized
as negative whereas medium and high expressions were
categorized as positive.The initial response to CRT was
documented at 8 ks post CRT and patients were followed
up for a minimum period of one year for locoregional
control and
survival.
Results
60% of the patients had p53 expression and 62% had Ki67
positivity.
Positive expression of p53 and Ki67 had a statistically
significant relative risk (RR) of 7.88 (p<0.001) and 3.36 (p
0.004) respectively for treatment failure at 8 weeks post
CRT. Similarly, positive expression of p53 and Ki67 had a
statistically significant relative risk (RR) of 6.32 (p<0.001)
and 3.30 (p<0.001) respectively for locoregional failure
and distant metastases at 1 year post CRT.
On multivariate analysis, the absence of p53 was a
statistically significant independent predictor for
complete response at 8 weeks and locoregional control at
1 year post CRT with an Odds ratio of 22.90 (p 0.0001) and
32.22 (p<0.0001) respectively. Likewise, the presence of
early nodal stage (N0 - N1) was a statistically significant
independent predictor for survival with an Odds ratio of
11.14 (p=0.0378).Positivity of p53 and Ki67 showed a RR
of 2.62 (p=0.64) and 2.44 (p=0.70) respectively, for
mortality, although their values did not reach statistical
significance.
Conclusion
The presence of p53 and Ki67 were associated with
significant risk of treatment failure, poor locoregional
control and distant metastasis whereas the absence of p53
and early nodal stage favored locoregional control and
survival respectively. These results signify the predicitve
roles of p53 and Ki67 in treatment of head and neck