Development of Anal Cancer Treatment selection model by Organoids (ACTOR)

Anal squamous cell carcinoma (SCC) is a rare form of cancer affecting the anal
canal. In the Netherlands, the prevalence of anal cancer has increased over the
past decade. The standard of care treatment for non-metastatic anal SCC is
definitive chemoradiotherapy. For patients with locally resistant or recurrent
disease, salvage surgery is used and has been reported to be offered in up to
40% of patients. Complete response is achieved in approximately 80% after
chemoradiotherapy with either 5-FU or capecitabine and mitomycin C. For
patients with metastatic anal SCC, carboplatin plus paclitaxel combination
chemotherapy is the current standard of care treatment with an objective
response rate of 59%. New developments are hampered due to rareness of disease
slowing done recruitment for clinical trials and testing novel agents.
Furthermore, there is a lack of in vitro and in vivo models for anal SCC and no
sufficiently good biomarkers are available to guide treatment in clinic.
Patient-derived organoid models offer a unique opportunity to study anal SCC.
These organoids can be derived from epithelial tumors, grown in 3D as miniature
versions of the original patient tumor in vitro. Organoids have many
advantages, the most prominent of which is the ability to recapitulate
intratumor heterogeneity in vitro and accurately represent the tumors they are
derived from both genetically and phenotypically. Additionally, compared to
traditional 2D-cell lines and xenograft models, for the majority of tumor
types, organoid generation is very rapid (within 10-14 days of the tissue
biopsy). This allows for fast establishment of a patient-derived organoid
culture, with the potential to perform in vitro drug screening assays within a
short timeframe to determine the sensitivities of a particular tumor to a
particular drug or compound. Organoids can be used as a platform for in vitro
drug screening to evaluate chemotherapy, radiotherapy as well as targeted
therapy and immunotherapy.

Aim of the ACTOR project is to develop organoid models for anal SCC, both in
the non-metastatic and in the metastatic setting to:
1) learn about the biology of disease by characterising the organoids and
original tissue, circulating immune cells and tumour infiltrating lymphocytes
(TILs) in order to find new leads for therapeutic options;
2) test the ability organoids to function as predictive biomarker for standard
of care therapies;
3) perform drug screens to investigate novel treatment options (organoids as
patients in the lab).

This is an observational cohort study. Tumor tissue will be collected from
either the primary tumor by a surgeon, or from a metastasis by a radiologist.
The biopsy specimen will be used to culture tumor organoids and isolate tumor
infiltrating lymphocytes(TILs). The tissue will also be used to enable RNA and
DNA sequencing. Novel therapies will be evaluated in organoids by testing a
panel of different agents targeting mutational pathways upregulated in anal
SCC. Finally, co-cultures with immune cells will be performed to evaluate
immunotherapy options Blood samples will be collected for germline DNA
background variation and for PBMC isolation. The patient will be treated
according to standard of care and clinical data of treatment type and survival
outcomes will be collected.

For all included patient*s biopsies of the (metastatic) lesion(s) in the anal
tumor, liver, lymph node or subcutaneous lesion will be performed taken in
order to obtain material for organoid cultures. Ample experience exists with
performing biopsies in patients with (metastatic) anal cancer and the procedure
is considered to be safe. Alongside the tumor biopsies, during the study 4
times blood will be drawn (20ml in total per time-slot). Patients will be
treated according to standard of care and clinical management of patients will
be performed according to daily practice in participating institutions.