Well-differentiated gastro-entero-pancreatic neuroendocrine tumors with positive FDG-PET/CT: a retrospective chart review

PURPOSE

Rarely, well-differentiated gastro-entero-pancreatic neuroendocrine tumors (GEP NETs) can have positive uptake on 18F-fluorodeoxyglucose-PET/computerized tomography ( 18 F-FDG-PET/CT), with or without a positive 68 Ga-PET/CT. We aim to evaluate the diagnostic role of 18 F-FDG-PET/CT in patients with well-differentiated GEP NETs.

METHODS

We retrospectively reviewed a chart of patients diagnosed with GEP NETs between 2014 and 2021, at the American University of Beirut Medical Center, who have low (G1; Ki-67 ≤2) or intermediate (G2; and Ki-67 >2-≤20) well-differentiated tumors with positive findings on FDG-PET/CT. The primary endpoint is progression-free survival (PFS) compared to historical control, and the secondary outcome is to describe their clinical outcome.

RESULTS

In total 8 out of 36 patients with G1 or G2 GEP NET met the inclusion criteria for this study. The median age was 60 years (range 51-75 years) and 75% were male. One patient (12.5%) had a G1 tumor whereas 7 (87.5%) had G2, and seven patients were stage IV. The primary tumor was intestinal in 62.5% of the patients and pancreatic in 37.5%. Seven patients had both 18 F-FDG-PET/CT and 68 Ga-PET/CT positive and one patient had a positive 18 F-FDG-PET/CT and negative 68 Ga-PET/CT. Median and mean PFS in patients positive for both 68 Ga-PET/CT and 18 F-FDG-PET/CT were 49.71 months and 37.5 months (95% CI, 20.7-54.3), respectively. PFS in these patients is lower than that reported in the literature for G1/G2 NETs with positive 68 Ga-PET/CT and negative FDG-PET/CT (37.5 vs. 71 months; P  = 0.0217).

CONCLUSION

A new prognostic score that includes 18 F-FDG-PET/CT in G1/G2 GEP NETs could identify more aggressive tumors.

Quality-of-life outcomes after total neoadjuvant short course radiotherapy, chemo-immunotherapy, and total mesorectal excision for locally advanced rectal cancer

63

Background: A growing body of evidence supports total neoadjuvant therapy (TNT) for locally advanced rectal cancer (LARC), however the optimal regimen is yet to be determined and little is known on the quality-of-life (QOL) implications of these therapies. We report QOL data from the Averectal study, which assessed the efficacy and safety of neoadjuvant short course radiotherapy (SCR) plus chemo-immunotherapy for patients with LARC. Methods: Between July 2018 and October 2020, patients enrolled in the Averectal study were invited to fill the Functional Assessment of Cancer Therapy for colorectal cancer (FACT-C) throughout their treatment. We analyzed results at baseline (T0), at completion of SCR and chemo-immunotherapy (T1), and at last-follow up after total mesorectal excision (TME) (T2). Paired sample t-test was used to compare mean scores for individual patients. Results: 39 patients completed the FACT-C form at the specified points. Median follow-up duration was 25.7 months. Median age was 58 years (range 31-74 years), 25 (64.1%) were males, 1 (3.1%) had stage II disease and the rest (96.9%) had stage III. All patients received SCR then 6 cycles of mFOLFOX-6 plus avelumab followed by TME. The mean score differences of the FACT-C subscales at different time-points are summarized. At the end of TNT, the social (SWB), emotional (EWB), functional well-being (FWB) and colorectal cancer subscale (CCS) scores improved compared to baseline (not significant) but physical well-being score (PWB) worsened (21.05 vs 22.94 p=0.025). After TME, all scores except EWB and FWB improved compared to T1, and all scores improved compared to baseline. The CCS, which assesses colorectal cancer specific concerns, significantly improved between T0 and T2 (19 vs 21.06, p=0.003). Overall, trial outcome index (TOI), reflecting functional status, improved after TME compared to baseline. Conclusions: Adopting neoadjuvant chemo-immuno-radiotherapy followed by TME for LARC does not result in QOL deterioration compared to baseline, and can improve colorectal cancer specific concerns. Clinical trial information: NCT03503630 . [Table: see text]

Assessment of immunoscore and MRI tumor regression grade to predict complete pathologic response in patients with locally advanced rectal cancer: Data from phase II Averectal study

212

Background: In patients with locally advanced rectal cancer (LARC), magnetic resonance imaging is the most accurate non-invasive staging tool, enabling response assessment to total neoadjuvant therapy. Wang et al had reported that 46.6% of patients with Magnetic Resonance Tumor Regression Grade 1 (mrTRG=1; complete radiologic response) achieved pathologic complete response (pCR; no residual tumor cells). We reported previously in a Phase II Averectal study the correlation between pre-treatment biopsy Immunoscore (IS) and pCR probability (68% ± 22 SD in patients with a high IS as opposed to 52% ± 22 SD in patients with a low IS; P=0.036). This study explores the value of combining IS and mrTRG to predict pCR among LARC patients. Methods: This is an open-label, single-arm multicenter stage-2 phase II study investigating the efficacy and safety of 5 fractions of short course radiotherapy, followed by 6 cycles of mFOLFOX-6 plus avelumab, followed by Total Mesorectal Excision (TME), in patients with LARC. Mean density percentiles of CD3 and CD8 positive T cells infiltrating the tumor and the invasive margin in baseline tissue samples were used to calculate IS (62% is considered the cutoff between high and low IS). Baseline and post treatment MRI were reviewed by two independent radiologists to measure mrTRG and other variables. Results: Between July 2018 and October 2020, 44 patients were accrued, out of which 40 (90%) completed at least 1 cycle of mFOLFOX/Avelumab and underwent TME. Of the 40, 36 (90%) had baseline IS, mrTRG (pre-post treatment) and pTRG (pathologic Tumor Regression Grade) assessed. Out of 36, 15 (41.6%) achieved pCR, 24 (66.7%) had mrTRG=1 and 22 (61%) had high IS. Of the high IS (n=22) patients, 10 (45.45%) achieved pCR. Also, out of 24 patients with mrTRG=1, 11 (45.8%) attained pCR. Most importantly, of the patients with combined high IS and mrTRG=1 (n=14), 11 (78.6%) achieved pCR. In patients with both mrTRG=1 and high IS, pCR rate was 78.6% (11/14). This result is significantly different from pCR rate for patients with either high IS (10/22, 45.45%) or mrTRG=1 (11/24, 45.8%) with P=0.0247 and P=0.0243 respectively. Conclusions: Combining both IS and mrTRG achieved a promising predictive value for pCR in LARC and therefore upon further validation may be potentially used for patient selection in non-operative management strategies. Clinical trial information: NCT03503630 .

A phase II single arm study of Nivolumab with stereotactic Ablative radiation Therapy after induction chemotherapy in CHOlangiocarcinoma (NATCHO)

BACKGROUND

Intrahepatic cholangiocarcinoma (CCA) is amongst the most common primary liver tumors worldwide. CCA carries a bad prognosis prompting research to establish new treatment modalities other than surgery and the current chemotherapeutic regimens adopted. Hence, this trial explores a new therapeutic approach, to combine stereotactic body radiation therapy (SBRT) and immunotherapy (Nivolumab), and asses its clinical benefit and safety profile after induction chemotherapy in CCA.

METHODOLOGY

This is a Phase II open-label, single-arm, multicenter study that investigates Nivolumab (PD-1 inhibitor) treatment at Day 1 followed by SBRT (30 Gy in 3 to 5 fractions) at Day 8, then monthly Nivolumab in 40 patients with non-resectable locally advanced, metastatic or recurrent intrahepatic or extrahepatic CCA. Eligible patients were those above 18 years of age with a pathologically and radiologically confirmed diagnosis of non-resectable locally advanced or metastatic or recurrent intrahepatic or extrahepatic CCA, following 4 cycles of cisplatin-based chemotherapy with an estimated life expectancy of more than 3 months, among other criteria. The primary endpoint is the progression free survival (PFS) rate at 8 months and disease control rate (DCR). The secondary endpoints are overall survival (OS), tumor response rate (TRR), duration of response, evaluation of biomarkers: CD3 + , CD4 + and CD8 + T cell infiltration, as well as any change in the PD-L1 expression through percutaneous core biopsy when compared with the baseline biopsy following 1 cycle of Nivolumab and SBRT.

DISCUSSION

SRBT alone showed promising results in the literature by both inducing the immune system locally and having abscopal effects on distant metastases. Moreover, given the prevalence of PD-L1 in solid tumors, targeting it or its receptor has become the mainstay of novel immunotherapeutic drugs use. A combination of both has never been explored in the scope of CCA and that is the aim of this study.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04648319 , April 20, 2018.

Total neoadjuvant therapy in patients with locally advanced rectal cancer: A tertiary medical center experience

The current standard of care for locally advanced rectal cancer (LARC) includes preoperative chemoradiation, followed by total mesorectal excision and adjuvant chemotherapy. This multimodality treatment improves local control but is associated with low compliance rates without clear beneficial effects on overall survival (OS) and distant metastasis. In this retrospective study, the charts of patients diagnosed with cT3/4 or cT2-node-positive rectal cancer between January 2011 and June 2019 were reviewed. The chemoradiation therapy (CRT) group received a long course of CRT with capecitabine followed by surgery and adjuvant chemotherapy. The total neoadjuvant therapy (TNT) group received 6 cycles mFOLFOX and a short course of radiation therapy followed by surgery. A total of 81 patients were included, among which 55 (67.9%) received CRT and 26 (32.1%) received TNT. In the CRT group, 15 (27.3%) patients achieved pathologic complete response (pCR) compared with 10 (38.5%) in the TNT group (P=0.22). A total of 19 (35.8%) cases in the CRT group downstaged to pT0N0 or pT1N0 compared with 11 (42.3%) in the TNT group (P=0.33). The 2-year disease-free survival (DFS) rate was 81.0% in the TNT group and 84.0% in the CRT group (P=0.15). Out of 55 patients in the CRT group, 30 patients received adjuvant chemotherapy, 22 (40.0% of CRT cases) of which completed a full course. All 26 patients in the TNT group received neoadjuvant chemotherapy, where 22 (84.6%) patients took a full course (P<0.001). In conclusion, the present study revealed that patients treated with TNT were more compliant to chemotherapy than those treated with CRT. A numerically higher pCR rate, and nodal and tumor downstaging were noted in the TNT group without significance. No difference was noted in the 2-year DFS. Longer follow-up is required.

Efficacy and safety-in analysis of short-course radiation followed by mFOLFOX-6 plus avelumab for locally advanced rectal adenocarcinoma

Background

Neoadjuvant chemotherapy and short-course radiotherapy followed by resection has been gaining recognition in the treatment of rectal cancer. Avelumab is a fully human immunoglobulin that binds Programmed Death-Ligand 1 (PD-L1) and prevents the suppression of the cytotoxic T cell immune response. This phase II trial evaluates the safety and pathologic response rate of short-course radiation followed by 6 cycles of mFOLFOX6 with avelumab in patients with locally advanced rectal cancer (LARC).

Methods

This study is prospective single-arm, multicenter phase II trial adopting Simon’s two-stage. Short-course radiation is given over 5 fractions to a total dose of 25 Gy. mFOLFOX6 plus avelumab (10 mg/kg) are given every 2 weeks for 6 cycles. Total mesorectal excision is performed 3–4 weeks after the last cycle of avelumab. Follow up after surgery is done every 3 months to a total of 36 months. Adverse event data collection is recorded at every visit.

Results

13 out of 44 patients with LARC were enrolled in the first stage of the study (30% from total sample size). All patients met the inclusion criteria and received the full short-course radiation course followed by 6 cycles of mFOLFOX6 plus avelumab. 12 out of the 13 patients completed TME while one patient had progression of disease and was dropped out of the study. The sample consisted of 9 (69%) males and 4 (31%) females with median age of 62 (33–73) years. The first interim analysis revealed that 3 (25%) patients achieved pathologic complete response (pCR) (tumor regression grade, TRG 0) out of 12. While 3 (25%) patients had near pCR with TRG 1. In total, 6 out of 12 patients (50%) had a major pathologic response. All patients were found to be MMR proficient. The protocol regimen was well tolerated with no serious adverse events of grade 4 reported.

Conclusion

In patients with LARC, neoadjuvant radiation followed by mFOLFOX6 with avelumab is safe with a promising pathologic response rate.

Trial Registration Number and Date of Registration ClinicalTrials.gov NCT03503630, April 20, 2018. https://clinicaltrials.gov/ct2/show/NCT03503630?term=NCT03503630&draw=2&rank=1.

Short-course radiation followed by mFOLFOX-6 plus avelumab for locally-advanced rectal adenocarcinoma

BACKGROUND

Current standard practice for locally advanced rectal cancer (LARC) entails a multidisciplinary approach that includes preoperative chemoradiotherapy, followed by total mesorectal excision, and then adjuvant chemotherapy. The latter has been accompanied by low compliance rates and no survival benefit in phase III randomized trials, so the strategy of administering neoadjuvant, rather than adjuvant, chemotherapy has been adapted by many trials, with improvement in pathologic complete response. Induction chemotherapy with oxaliplatin has been shown to have increased efficacy in rectal cancer, while short-course radiation therapy with consolidation chemotherapy increased short-term overall survival rate and decreased toxicity levels, making it cheaper and more convenient than long-course radiation therapy. This led to recognition of total neoadjuvant therapy as a valid treatment approach in many guidelines despite limited available survival data. With the upregulation (PDL-1) expression in rectal tumors after radiotherapy and the increased use of in malignant melanoma, the novel approach of combining immunotherapy with chemotherapy after radiation may have a role in further increasing pCR and improving overall outcomes in rectal cancer.

METHODS

The study is an open label single arm multi- center phase II trial. Forty-four recruited LARC patients will receive 5Gy x 5fractions of SCRT, followed by 6 cycles of mFOLFOX-6 plus avelumab, before TME is performed. The hypothesis is that the addition of avelumab to mFOLFOX-6, administered following SCRT, will improve pCR and overall outcomes. The primary outcome measure is the proportion of patients who achieve a pCR, defined as no viable tumor cells on the excised specimen. Secondary objectives are to evaluate 3-year progression-free survival, tumor response to treatment (tumor regression grades 0 & 1), density of tumor-infiltrating lymphocytes, correlation of baseline Immunoscore with pCR rates and changes in PD-L1 expression.

DISCUSSION

Recent studies show an increase in PD-L1 expression and density of CD8+ TILs after CRT in rectal cancer patients, implying a potential role for combinatory strategies using PD-L1- and programmed-death- 1 inhibiting drugs. We aim through this study to evaluate pCR following SCRT, followed by mFOLFOX-6 with avelumab, and then TME procedure in patients with LARC.

TRIAL REGISTRATION

Trial Registration Number and Date of Registration: ClinicalTrials.gov NCT03503630, April 20, 2018.

Short-course radiation followed by mFOLFOX-6 plus avelumab for locally advanced rectal adenocarcinoma

139

Background: Total neoadjuvant treatment (TNT) for locally advanced rectal cancer is becoming an accepted approach over the last few years with increasing pathologic complete response (pCR) and compliance of patients for chemotherapy in comparison with the current standard of care i.e., fluoropyrimidine based chemoradiation followed by surgery and adjuvant chemotherapy. Sequential use checkpoint inhibitors after radiation therapy (RT) has demonstrated synergistic effect in vivo leading to decrease in size of irradiated and non-irradiated secondary tumors outside the radiation field (abscopal effect). Methods: This is an investigator initiated; open-label, single-arm multicenter phase II study, adopting Simon’s two-stage aiming at evaluating the pCR rate and safety of using short-course radiation therapy (25 Grays in 5 fractions), followed by 6 cycles of mFOLFOX-6 plus Avelumab (anti PDL1), then total mesorectal excision(TME) in patients with locally-advanced, potentially resectable rectal adenocarcinoma. Results: 13 out of 44 patients were accrued from 20, July till 28, Dec 2018 in the first stage of the study (30% from total sample size). They all met the inclusion criteria and received full protocol treatment. 12 out of the 13 completed TME. 1 of the 13 had progression of disease, so surgery was aborted and patient was dropped out the study. The sample consisted of 9 (69%) males and 4 (31%) females with median age of 62 (33.0, 73.0) years. The first interim analysis revealed 3 patients (25%) achieved pCR (tumor regression grade: TRG = 0) out of 12 as compared to the historical control group with pCR of 16%. For the rest of the patients, 3 (25%) had major pathologic response rate (pRR) with TRG = 1 (< 10% viable cells is tumor bed).In total, 6 out of 12 patients (50%) had major pathologic response rate. As for safety, no serious adverse events of grade 3 and 4 were reported. Conclusions: Based on the first interim analysis results, incorporation of Avelumab and short course radiotherapy is tolerable in patients with locally advanced rectal cancer treated with TNT. The study will resume recruitment to reach the target accrual. Clinical trial information: NCT03503630.