Abstract 107P
Background
Tumor stroma consists of a complex network of safeguards for tumor proliferation. Tumour stromal imaging using fibroblast-activated protein-tagged radionuclide provides a metabolic-radiological quantum of tumor stromal content. Tumors rich in stroma have been traditionally associated with poorer disease-free outcomes. Our study correlates between standard uptake values (SUV) in fibroblast imaging to tumor stromal ratio evaluated pathologically and the response to radiation therapy in locally advanced carcinoma rectum.
Methods
50 patients of carcinoma Rectum with all patients having undergone cancer associated Fibroblast PET CT scan prior to starting neoadjuvant chemoradiation. Tumors having SUV max > 10 were considered as High. Metabolic activity in tumor site was compared to Tumor stromal ratio and response to radiation was evaluated in histopathological report. Patients were classified into High TSR (<50% Stromal content) and Low Tumor Stroma Ratio (>50% Stromal content).
Results
7 patients who had complete pathological response all had high TSR and SUV mean 20.4. 34 patients had <50% residual disease 67% had high TSR and SUV mean 17.6 and 34% had low TSR and SUV mean of 21.44. 9 patients had >50% residual disease had 77% low TSR and high SUV mean 25.11(Range- 9.51-92.33). Patients with both Low TSR [ >50% stromal content] and SUV Max > 10 have poor pathological response compared to patients with low TSR. In the low stromal content irrespective of SUV the local control was good. Table: 107P
| High TSR | Low TSR | High SUV | Low SUV | |
| Complete response | 7(32%) | 0 | 4(15.4%) | 3(12.5%) |
| <50% Residual disease | 23(71.8%) | 11(61%) | 14(53.8%) | 20(83.3%) |
| >50% Residual disease | 2(6.2%) | 7(39%) | 8(30.8%) | 1(4.2%) |
Conclusions
High Tumor Stromal Ratio showed better complete and partial response to neoadjuvant chemoradiation in locally advanced carcinoma rectum. Tumors with high stromal content were observed to have higher SUV values in fibroblast stromal imaging and the same were also more commonly associated with suboptimal response. The need for dose escalation for the same has to be explored for better tumor control.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
497P - Sintilimab in combination with anlotinib in advanced NSCLC treated with first-line PD-1 antibodies: An open, single-arm, phase II trial
Presenter: Ying Jin
Session: Poster Display
Resources:
Abstract
498P - Frailty-adjusted life expectancy and survival in older lung cancer patients: A large-scale electronic health-record based study
Presenter: Thao Tu
Session: Poster Display
Resources:
Abstract
499P - Long-term survival and treatment (tx) patterns after first-line (1L) osimertinib in patients (pts) with epidermal growth factor receptor (EGFR) mutation-positive (m) advanced non-small cell lung cancer (NSCLC): Japanese cohort of a global real-world (rw) observational study
Presenter: Daichi Fujimoto
Session: Poster Display
Resources:
Abstract
500P - The effectiveness and safety of durvalumab after chemoradiotherapy for locoregional recurrence of completely resected non-small cell lung cancer: Real-world, multicenter, observational study (NEJ056)
Presenter: Hidehito Horinouchi
Session: Poster Display
Resources:
Abstract
501P - One-year survival outcomes of unresectable stage III non-small cell lung cancer patients who underwent PD-1 inhibitor plus chemo as induction therapy
Presenter: Xin Wang
Session: Poster Display
Resources:
Abstract
502P - Impact of sarcopenia on the outcome of patients with locally advanced non-small cell lung cancer treated with chemoradiotherapy followed by durvalumab
Presenter: Kentaro Tamura
Session: Poster Display
Resources:
Abstract
503P - Clinical outcomes by infusion timing of immune checkpoint inhibitors in patients with locally advanced NSCLC
Presenter: TSUYOSHI HIRATA
Session: Poster Display
Resources:
Abstract
504P - Real-world outcomes with induction systemic therapy for stage III in eligible for upfront local therapy: Pre vs post immunotherapy era in a tertiary referral centre
Presenter: Praveen Kumar Marimuthu
Session: Poster Display
Resources:
Abstract
505P - Neoadjuvant PD-1 inhibitor (tislelizumab) plus platinum–etoposide in patients with limited-stage small cell lung cancer: A phase II trial
Presenter: Junjie Hu
Session: Poster Display
Resources:
Abstract
506P - Intrathoracic progression is still the most dominant failure pattern after first-line chemo-immunotherapy in extensive-stage small-cell lung cancer: Implications for thoracic radiotherapy
Presenter: Byoung Hyuck Kim
Session: Poster Display
Resources:
Abstract