p16 and PD-L1 expression in locoregional squamous cell carcinoma of the anal canal – A single center retrospective analysis in Japan

Date

21 Oct 2018

Session

Poster display session: Basic science, Endocrine tumours, Gastrointestinal tumours - colorectal & non-colorectal, Head and neck cancer (excluding thyroid), Melanoma and other skin tumours, Neuroendocrine tumours, Thyroid cancer, Tumour biology & pathology

Presenters

Ryo Takahashi

Citation

Annals of Oncology (2018) 29 (suppl_8): viii150-viii204. 10.1093/annonc/mdy281

Authors

R. Takahashi¹, T. Wakatsuki¹, N. Yamamoto², S. Taguchi³, E. Shinozaki¹, H. Osumi¹, M. Ogura¹, T. Ichimura¹, D. Takahari¹, M. Suenaga¹, K. Chin¹, M. Oguchi³, M. Ueno¹, K. Yamaguchi¹

Author affiliations

¹ Department Of Gastroenterology, Cancer Institute Hospital of JFCR, 135-8550 - Tokyo/JP
² Department Of Pathology, Cancer Institute Hospital of JFCR, 135-8550 - Tokyo/JP
³ Department Of Radiotherapy, Cancer Institute Hospital of JFCR, 135-8550 - Tokyo/JP

Abstract 3329

Background

Squamous cell carcinoma of the anal canal (SCCA) is a rare malignancy especially in Asia. It is widely known that SCCA is linked to prior infection with human papillomavirus (HPV) in western countries. However, it is unclear whether HPV is associated with SCCA in Japan. In addition, expression of PD-L1, potential predictive marker for anti-PD-1 antibody, and its prognostic impact on locoregional SCCA remain to be elucidated. The aim of this study is to examine expression rates and prognostic impact of p16 and PD-L1 in Japanese patients with SCCA.

Methods

34 patients with locoregional SCCA were treated by concurrent CRT at the Cancer Institute Hospital between 2007 and 2017. Among them, 28 patients whose biopsy specimens were available were enrolled. Radiation consisted of 45.0-59.4 Gy. Chemotherapy was given during radiation: 1000mg/m² daily fluorouracil on day 1-4 and 29-32, and a single dose of mitomycin C 10mg/m² administered on day 1 and 29. Data on relapse and death were obtained until March 2018. p16 positive was defined as p16 was stained on tumor nuclei. PD-L1 positive was also defined as PD-L1 was overexpressed on tumor membrane with more than 2+ score and the area was more than 5%.

Results

Of 28 patients, the median age was 59 (range 35-82) years. Male to female sex ratio was 1:6. 6 (21.4%) were clinically staged as I, 4 (14.3%) as II, 5 (17.9%) as IIIA, and 13 (46.4%) as IIIB. SCCA remained or recurred in 1 with cStage II, 1 with cStage IIIA and 7 with cStage IIIB. 3-year disease free survival (DFS) was 65.8% (95%CI, 44.3-80.6%), and 3-year overall survival (OS) was 79.2% (95%CI, 53.4-91.7%). Of 28 cases, 27 (96.4%) were positive for p16, and 6 (21.4%) were positive for PD-L1. In univariate analysis for DFS and OS, lymph node metastasis was significantly related to poor outcomes (DFS, p = 0.0289; OS, p < 0.0001). T factor (p < 0.0001) and tumor stage (p = 0.0035) significantly influenced OS. No significantly difference was found in terms of PD-L1 expression (DFS, p = 0.595; OS, p = 0.544).

Conclusions

High expression rate of p16 was observed in Japanese patients with locoregional SCCA. Lymph node metastasis, advanced T factor and tumor stage were negative prognostic factors for CRT, but no prognostic impact of PD-L1 was found.

Clinical trial identification

Legal entity responsible for the study

Ryo Takahashi.

Funding

Has not received any funding.

Editorial Acknowledgement

Disclosure

All authors have declared no conflicts of interest.

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Presenter: Lola-Jade Palmieri

Session: Poster display session: Basic science, Endocrine tumours, Gastrointestinal tumours - colorectal & non-colorectal, Head and neck cancer (excluding thyroid), Melanoma and other skin tumours, Neuroendocrine tumours, Thyroid cancer, Tumour biology & pathology

Resources:

Abstract

21 Oct 2018