Paraneoplastic Cutaneous Manifestations of Hepatocellular Carcinoma. A Systematic Review and Meta-analysis

Background: There remains a scarcity of published data on the clinical significance of paraneoplastic cutaneous manifestations in hepatocellular carcinoma (HCC). Method: A systematic search of MEDLINE was performed in December 2022. Inclusion criteria comprised studies reporting on patients with HCC, who had paraneoplastic cutaneous manifestations. Outcomes of interests comprise survival and response to cancer-directed and/or skin directed therapy. Results: A total of 48 studies comprising 60 HCC patients were included in the analysis. The most frequent reported skin abnormalities were dermatomyositis, pityriasis rotunda, and porphyria. Most patients presented with dermatomyositis had underlying viral hepatitis, while all reported porphyria and acanthosis cases were associated with metabolic causes of HCC, such as steatosis. Paraneoplastic skin changes were more common in patients with metastatic disease. Pityriasis Rotunda was associated with the lowest risk of death, (OR: 0.05, 95% CI: 0.003 to 0.89; p = 0.04), while dermatomyositis had a statistically significant higher risk of death (OR: 3.37, 95% CI: 1.01-12.1; p = 0.03). Most patients showed an improvement in their cutaneous abnormalities, following cancer-directed therapy. Conclusion: Paraneoplastic cutaneous manifestations are reported more frequently in patients with a higher burden of disease, especially presence of metastases. Certain cutaneous manifestations have prognostic implication.

Utility of ctDNA in predicting relapse in solid tumors after curative therapy: a meta-analysis

BACKGROUND

Presence of circulating tumor DNA (ctDNA) is prognostic in solid tumors treated with curative intent. Studies have evaluated ctDNA at specific 'landmark' or multiple 'surveillance' timepoints. However, variable results have led to uncertainty about its clinical validity.

METHODS

PubMed search identified relevant studies evaluating ctDNA monitoring in solid tumors after curative intent therapy. Odds ratios (OR) for recurrence at both landmark and surveillance time points for each study were calculated and pooled in a meta-analysis using the Peto method. Pooled sensitivity and specificity weighted by individual study inverse variance were estimated and meta-regression utilizing linear regression weighted by inverse variance was performed to explore associations between patient and tumor characteristics and the OR for disease recurrence.

RESULTS

Of 39 studies identified; 30 (1924 patients) and 24 studies (1516 patients) reported on landmark and surveillance time points respectively. The pooled OR for recurrence at landmark was 15.47 (95% CI 11.84 - 20.22) and at surveillance was 31.0 (95% CI 23.9-40.2) The pooled sensitivity for ctDNA at landmark and surveillance analyses were 58.3% and 82.2%. The corresponding specificities were 92% and 94.1%. Prognostic accuracy was lower with tumor agnostic panels and higher with longer time to landmark analysis, number of surveillance draws and smoking history. Adjuvant chemotherapy negatively impacted landmark specificity.

CONCLUSIONS

Although prognostic accuracy of ctDNA is high, it has low sensitivity, borderline high specificity, and therefore modest discriminatory accuracy, especially for landmark analyses. Adequately designed clinical trials with appropriate testing strategies and assay parameters are required to demonstrate clinical utility.

Abstract P4-07-02: Toxicity profile of single agent trastuzumab deruxtecan in solid tumors: A meta-analysis

Background: Trastuzumab deruxtecan (T-DXd) has been evaluated in numerous solid tumors and has been approved for metastatic HER2-positive breast and gastric/gastroesophageal cancers. We aimed to provide a precise estimate of toxicity of T-DXd observed in clinical trials. Methods: A systematic literature search was performed in PubMed and supplemented by review of abstracts from ASCO and ESMO. Eligible studies were clinical trials (dose-expansion phase 1, phase 2, and phase 3) investigating single agent T-DXd. The search was performed in June 2022. For single-arm trials, meta-analysis comprised one-sample proportions to obtain the random effects estimates of toxicity and respective 95% confidence intervals (CI) for T-DXd, while for randomized trials, the Mantel-Haenszel odds ratio method was utilized. Results: Fifteen trials comprising 1566 participants were evaluable for toxicity. ECOG Performance Status (PS) was reported in 11 studies and was ≥ 2 in only a single patient. The median age at enrollment was reported for 13 studies and was 57.5 years. Seven trials comprising 1023 (65.3%) participants evaluated T-DXd for breast cancer. From available data, 1209/1440 (84%)of participants were female and 735/1551 (47%) were from East Asia. The median follow-up time was 11.1 months (13 studies) and median previous lines of treatment were 3 (12 studies). All-grade toxicity rate of ≥10% was reported for most toxicities; however, grade ≥3 toxicity rate of ≥10% was reported only for neutropenia and anemia; 17.4% (95%CI 12-22.8) and 14.8% (95%CI 8.6-21), respectively (Table 1). Interstitial lung disease/pneumonitis (ILD) was reported in 203 (12.4%) patients, including 160 (9.41%) grade 1-2, and 23 (1.1%) grade 3-4. Treatment-related death was reported in 20 (1%) patients, and all were due to grade 5 ILD. No significant difference in ILD was identified in subgroup analysis of trials conducted in east Asia vs. the rest of the world, breast vs. other solid tumors, 5.4mg/kg vs. other doses, median follow-up < 12 months vs. ≥12 months or median previous lines ≥3 vs. < 3. In the three randomized clinical trials, grade ≥3 toxicity was significantly higher for nausea (OR: 9.32, 95%CI: 2.53-34.32), ILD (OR: 5.35, 95%CI: 0.97, 29.48), fatigue (OR:2.5, 95%CI: 1.11-5.66), and anemia (OR:1.77 95%CI: 1.14-2.74). Conclusions: T-DXd was associated with infrequent grade ≥3 toxicities across clinical trials. Grade 1-2 ILD was more common; however, grade 3-4 ILD occurred in 1.1%. This may be related to active monitoring of this toxicity in clinical trials and discontinuation of treatment in participants with G2 ILD. There is lack of evidence for the safety of T-DXd in patients with ECOG PS ≥ 2.

Citation Format: Faris Tamimi, Abhenil Mittal, Consolacion Molto Valiente, Massimo Di Iorio, Laith Al-Showbaki, Michelle Nadler, Eitan Amir. Toxicity profile of single agent trastuzumab deruxtecan in solid tumors: A meta-analysis [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-02.

Changes in circulating tumor DNA and outcomes in solid tumors treated with immune checkpoint inhibitors: a systematic review

BACKGROUND

Quantification of circulating tumor DNA (ctDNA) levels is a reliable prognostic tool in several malignancies. Dynamic changes in ctDNA levels in response to treatment may also provide prognostic information. Here, we explore the value of changes in ctDNA levels in response to immune checkpoint inhibitors (ICIs).

METHODS

We searched MEDLINE (host: PubMed) for trials of ICIs in advanced solid tumors in which outcomes were reported based on change in ctDNA levels. ctDNA reduction was defined as reported in individual trials. Typically, this was either >50% reduction or a reduction to undetectable levels. We extracted HRs and related 95% CIs and/or p values comparing ctDNA reduction versus no reduction for progression-free survival (PFS) and/or overall survival (OS). Data were then pooled in a meta-analysis. Variation in effect size was examined using subgroup analyses.

RESULTS

Eighteen trials were included in the meta-analysis. ctDNA levels were detectable in all participants in all studies prior to initiation of ICIs. A reduction in ctDNA measured 6-16 weeks after starting treatment was associated with significantly better PFS (HR 0.20; 95% CI, 0.14 to 0.28; p<0.001). Similarly, OS was superior in patients with reduced ctDNA levels (HR 0.18; 95% CI, 0.12 to 0.26; p<0.001). The results were consistent across all disease sites, lines of treatment, magnitude of change (to undetectable vs >50% reduction) and whether treatment exposure comprised single or combination ICIs.

CONCLUSIONS

In advanced solid tumors, a reduction in ctDNA levels in response to ICIs is associated with substantial improvements in outcome. ctDNA change is an early response biomarker which may allow for de-escalation of cross-sectional imaging in patients receiving ICIs or support treatment de-escalation strategies.

Three-year disease-free survival in randomized trials of neoadjuvant chemotherapy and HER2-targeted therapy in breast cancer: A meta-analysis

BACKGROUND

Outcomes for breast cancer patients with residual disease (RD) after neoadjuvant chemotherapy (NACT) and HER2-targeted therapy may be better than anticipated leading to a smaller absolute benefit of adjuvant trastuzumab emtansine (T-DM1). Therefore, accurate estimates of 3-year disease-free survival (DFS) can aid in treatment planning.

METHODS

We reviewed randomized trials of NACT and HER2-targeted therapy in breast cancer (excluding T-DM1) and calculated mean 3-year DFS weighted by study sample size. Meta-regression comprising linear regression weighted by sample size (mixed-effects) was performed to explore associations between 3-year DFS and year of accrual and trial-level patient, disease, and treatment factors. Data were reported quantitatively irrespective of statistical significance.

RESULTS

Eleven studies (N = 3581) were included in the primary analysis. The mean 3-year DFS for patients with RD was 79.7% (95% CI 77.4-80.9). This was higher for trials completing accrual after 2010 [83% (95% CI 79.3-86.3)] and for those receiving dual HER2 targeted therapy [83.4% (95% CI 79.2-87.7]. Better outcomes for ER positivity, later accrual and dual Her-2 targeted therapy were confirmed in meta-regression. Negative quantitative significance was observed for larger clinical tumor size and nodal involvement.

CONCLUSIONS

The 3-year DFS for patients with RD has improved over time possibly due to dual HER2 targeted therapy. This will reduce the absolute benefit of adjuvant T-DM1 in this group of patients.

Changes in circulating tumor DNA (ctDNA) and outcomes in solid tumors treated with immune checkpoint inhibitors (ICIs)

2544

Background: Quantification of ctDNA levels can be a reliable prognostic tool in several malignancies. More recently, detection of genomic alterations in ctDNA have been validated as a predictive biomarker to guide treatment planning. Dynamic changes in ctDNA levels over time and in response to treatment may also provide prognostic information. However, less is known about the value of changes to ctDNA levels in response to immune checkpoint inhibitors (ICIs). Methods: We searched MEDLINE (host:PubMed) and reviewed trials exploring outcomes of patients with advanced solid tumors receiving ICIs in which outcomes were reported based on changes to ctDNA levels. ctDNA clearance was defined as reported in individual trials. Typically, this was defined as either >50% reduction or a reduction to undetectable levels. We extracted progression free survival (PFS) and/or overall survival (OS) values, related 95% Confidence intervals (CI) and/or p-values. Data were then included in a meta-analysis utilizing the generic inverse variance and random effects model. Variation in effect size was examined using random effects meta-regression analysis. Results: A total of 17 trials were included in the meta-analysis; ctDNA levels were detectable in all participants in all studies prior to initiation of ICIs. Method of detection included next generation sequencing and/or droplet digital polymerase chain reaction assays. Overall, low to undetectable ctDNA levels, measured 6-16 weeks after starting treatment was associated with significantly better PFS, (HR 0.20 95% CI, 0.14-0.28; p<0.001). Similarly, OS was superior in patients with substantially reduced or undetectable ctDNA levels after receiving ICIs, (HR 0.18, 95% CI, 0.12-0.26; p<0.001. The results were consistent across all disease sites, lines of treatment, level of change (undetectable vs. >50% reduction) and whether treatment exposure comprised single or multiple ICIs (see Table). Conclusions: In unselected advanced solid tumors, a substantial fall in ctDNA levels in response to ICIs is associated with substantial improvements in both PFS and OS. ctDNA change is an early response biomarker which may allow for de-escalation of cross-sectional imaging in patients receiving ICIs, or support treatment de-escalation strategies. Further research is needed to quantify variations in sensitivity between the available NGS assays, as well as differences discovery range between assay platforms. [Table: see text]

Test performance and clinical validity of circulating tumor DNA (ctDNA) in predicting relapse in solid tumors treated with curative intent therapy

3036

Background: Studies have explored the prognostic value of ctDNA in predicting relapse in solid tumors treated with curative intent. These studies have evaluated ctDNA at specific ‘landmark’ timepoint or over numerous ‘surveillance’ time points. However, variable results have led to uncertainty about the clinical validity of this tool. Here, we quantify the predictive and discriminatory accuracy of ctDNA and explore sources of heterogeneity at both landmark and surveillance time points across different tumor sites. Methods: A search of MEDLINE (host: PubMed) identified studies evaluating ctDNA after curative intent therapy in solid tumors. Odds ratios (OR) for disease recurrence at both landmark and surveillance time points for each study were calculated and pooled in a meta-analysis using the Peto method. Pooled sensitivity and specificity weighted by individual study inverse variance were estimated and meta-regression utilizing linear regression weighted by inverse variance was performed to explore associations between patient and tumor characteristics and the OR for disease recurrence. Results: Of 23 studies identified; 16 (750 patients) and 14 studies (853 patients) reported on landmark and surveillance time points respectively. The median time from completion of definitive therapy to landmark testing was 51.5 days (range 3-120). The pooled OR for recurrence at landmark was 22.22 (95% CI 14.82-33.30) and at surveillance was 27.51 (95% CI 19.1-39.63). The pooled sensitivity for ctDNA at landmark and surveillance time points were 59.9% and 73.2%. The corresponding specificities were 90.9% and 86.6%. Subgroup results are shown in the table. There was lower predictive accuracy with the use of tumor site specific panels, in patients receiving adjuvant chemotherapy and in lung cancer. Meta-regression showed that longer time to landmark and higher number of surveillance blood draws were associated with higher prognostic accuracy, as was a history of smoking. Conclusions: Although ctDNA at both landmark and surveillance time points shows high prognostic accuracy, it has low sensitivity, suboptimal specificity and therefore weak discriminatory accuracy to predict relapse in patients with solid tumors treated with curative intent. Testing methodology, time points and patient populations need to be optimized before it can be incorporated routinely in clinical practice.[Table: see text]

Three-year disease-free survival in randomized trials of chemotherapy and HER2-targeted therapy: A meta-analysis

579

Background: The Katherine trial reported a 3-year invasive disease-free survival (DFS) of 77% in patients not achieving pathological complete response (pCR) and continuing on adjuvant trastuzumab. Case series suggest better outcomes and data support that some patients with residual disease have similar outcomes to those with pCR (Steenbruggen et al). The absolute benefit of adjuvant trastuzumab emtansine (T-DM1) would be smaller in patients with favourable outcomes despite residual disease. As such, a more precise estimate of 3-year DFS is needed for treatment planning. Methods: We reviewed reports of randomized trials of neoadjuvant chemotherapy and HER2-directed therapy and extracted the 3-year DFS, a validated surrogate endpoint in HER2-positive early-stage breast cancer. Data were extracted for patients with residual disease and with pCR. The mean 3-year DFS weighted by study sample size was calculated. Meta-regression comprising linear regression weighted by sample size (mixed effects) was performed to explore associations between 3-year DFS and trial-level patient, disease and treatment factors and changes in 3-year DFS over time. Quantitative significance was explored using methods described by Burnand et al. Results: Eleven studies comprising 3908 patients were included in the analysis. The mean 3-year DFS for patients with pCR and for residual disease was 90.1% and 80.0%, respectively. DFS improved over time. For trials whose final year of accrual was after 2010, mean 3-year DFS for residual disease was 84.7% compared to 78.0% for trials completing accrual before that time (p<0.001). In a subgroup analysis of patients with residual disease, those receiving dual HER2-targeted therapy in the neoadjuvant setting had a 3-year DFS of 85.3% compared to 73.3% for those receiving only trastuzumab (p<0.001). Meta-regression results for residual disease are shown in the Table. Positive quantitative significance was observed for final year of accrual, ER-expression, dual anti-HER2 therapy and concurrent vs sequential anti-HER2 therapy. Negative quantitative significance was observed for larger clinical tumor size and nodal involvement. Conclusions: 3-year DFS for patients with residual disease and HER2-targeted therapy is better than reported in the Katherine trial and has improved over time, possibly due to increased use of dual HER2-targeted therapy in the neoadjuvant setting. In this context, the absolute benefit of adjuvant T-DM1 may be smaller than anticipated. [Table: see text]

A retrospective analysis of changes in distant and breast cancer related disease-free survival events in adjuvant breast cancer trials over time

Disease-free survival (DFS) comprises both breast cancer and non-breast cancer events. DFS has not been validated as a surrogate endpoint for overall survival (OS) in most breast cancer subtypes. We assessed changes to the type of events contributing to DFS over time. We identified adjuvant studies in breast cancer (BC) from 2000 to 2020 where the endpoint was DFS. We examined change in distant DFS events and the BC-related DFS using univariable and multivariable linear regression. Data were reported quantitatively using the Burnand criteria irrespective of statistical significance. We included 84 studies (88 cohorts), comprising 212,191 participants, 41,604 DFS events and 23,205 distant DFS events. The DFS event rate/100 participants/year has declined modestly over time (ß - 0.34, p = 0.001). Start year was negatively associated with distant DFS events (ß - 0.58, p < 0.0001); however, the effect was lost after adjusting for follow-up time (ß - 0.18, p = 0.096). The average number of BC-related events/100 participants/year also declined over time (ß - 0.28, p = 0.009). In multivariable analysis, start year and ER expression were quantitatively associated with distant DFS events and BC-related DFS events. DFS events have declined over time driven by a reduction in BC related events. As DFS events are increasingly defined by non-BC events, there will be limited surrogacy between DFS and OS.

OUP accepted manuscript

Background

Many randomized control trials (RCTs) evaluating programmed death receptor-1 (PD-1)/programmed death ligand-1 (PD-L1) targeting monoclonal antibodies (mAbs) have been completed or are in progress. We examined hypothesized hazard ratios (HHRs) and observed hazard ratios (OHRs) from published RCTs evaluating these mAbs.

Methods

Publications of RCTs evaluating at least one PD-1/PD-L1 targeting mAbs approved by the US Food and Drug Administration were identified through PubMed searches. The primary reports of RCTs were retrieved. Two investigators extracted HHR, OHR for the primary endpoint among other data elements independently. The differences (∆HR) in HHR and OHR were analyzed statistically. A separate search was conducted for secondary reports after longer follow-ups, the updated OHR was extracted.

Results

Forty-nine RCTs enrolling 36 867 patients were included. The mean HHR and OHR were 0.672 and 0.738 respectively. The mean ∆HR was 0.067 (range: –0.300 to 0.895; 95% confidence interval (CI), 0.003-0.130). HHR was met or exceeded in 22 (45%) RCTs. OHR was ≥ 1.0 in 6 RCTs (12%). PD-L1 expression was not associated with the magnitude of effect. Of 18 RCTs with follow-up reports, the magnitude of benefit decreased in 8 RCTs with extended follow-ups.

Conclusion

The majority of published RCTs evaluating PD-1/PD-L1 targeting mAbs did not achieve their hypothesized magnitude of benefit. The optimism bias requires attention from the cancer clinical research community given the number of these agents in development and the intense interest in evaluating these agents in a variety of disease settings.

Optimism bias in the design of phase III randomized control trials (RCTs) evaluating PD-1/PD-L1 targeting monoclonal antibodies (mAbs)

e18616

Background: PD-1/PD-L1 targeting monoclonal antibodies (mAbs) improve outcomes in multiple cancer types. Multiple mAbs are in clinical development, and many randomized control trials (RCTs) have been completed or are in progress. These RCTs compete for limited clinical trials infrastructure, human resources and patients. Since the hypothesized benefit of an intervention is a critical determinant of the number of patients required for an RCT, it is crucial that the expected benefit be estimated appropriately. We examined the hypothesized hazard ratio (HHR) and the observed hazard ratio (OHR) in RCTs evaluating PD-1/PD-L1 targeting mAbs. Methods: Publications of RCTs evaluating at least one PD-1/PD-L1 targeting mAbs approved by the US Food and Drug Administration were identified through PubMed searches. The primary publication for each RCT and its associated protocol were retrieved. Two investigators independently extracted HHR, OHR for the primary endpoint among other data elements. The differences (∆HR) in HHR and OHR were analyzed statistically. Updated OHRs (uOHR) were extracted from reports with extended follow-ups. Results: 49 RCTs enrolling 36867 patients were included. 45/49 RCTs were in the palliative setting. HHR was met or exceeded in 22 (45%) RCTs. The mean HHR and OHR were 0.672 and 0.738, respectively. The mean ∆HR was 0.067 (range: -0.300 to 0.895, 95% confidence interval = 0.003 – 0.130). A lower magnitude of effect than hypothesized in 12/29 RCTs in non-small cell lung cancer, melanoma and renal cell carcinoma, but in 15/20 RCTs in other cancer types. OHR was ≥ 1.0 in 6 RCTs (12%). In the palliative setting, ∆HR was larger in more heavily pre-treated patients. PD-L1 expression was not associated with magnitude of effect. However, a higher magnitude of effect was observed for RCTs published in the New England Journal of Medicine. For 18 RCTs with extended follow-ups, uOHR was higher than OHR in 8. Conclusions: The majority of published RCTs evaluating PD-1/PD-L1 targeting mAbs did not achieve their hypothesized magnitude of effect. Investigators’ optimism regarding these agents should be combined with more realistic expectations. The optimism bias requires attention from the cancer clinical research community given the number of these agents in development and the intense interest in evaluating these agents in various disease settings.

Network Meta-analysis Comparing Efficacy, Safety and Tolerability of Anti-PD-1/PD-L1 Antibodies in Solid Cancers

Background: Multiple anti-PD-1/PD-L1 antibodies have been approved, and in some diseases, there is a choice of more than one. Comparative efficacy, safety and tolerability are unknown.

Methods: Randomized trials (RCTs) supporting the registration of single agent anti-PD1 or anti-PDL1 inhibitors between 2015-2019 were identified. We extracted the hazard ratio (HR) for overall survival (OS) and calculated the odds ratio (OR) for commonly reported safety and tolerability outcomes. We then performed a network meta-analysis, reporting multiple pair-wise comparisons between different anti-PD-1/PD-L1 antibodies.

Results: Sixteen RCTs comprising 10673 patients were included; 10 in non-small-cell lung cancer, 2 in melanoma, 2 in head and neck squamous cell carcinoma and 2 in urothelial cancer. Compared to pembrolizumab, efficacy was similar for nivolumab (HR: 1.02 95% CI: 0.91-1.14) and for atezolizumab (HR: 0.97 95% CI: 0.85-1.10), however, avelumab appeared inferior (HR: 1.30, 95% CI: 1.06-1.56). Pembrolizumab showed similar odds of serious adverse events (SAEs) as nivolumab (OR: 1.12, 95% CI: 0.56-2.27) and atezolizumab (OR: 1.05, 95% CI: 0.55-2.04). Compared to nivolumab, atezolizumab was associated with more SAEs (OR: 2.14, 95% CI: 1.47-3.12). Avelumab had the lowest odds of grade 3-4 adverse events compared to pembrolizumab (OR: 0.42, 95% CI: 0.24-0.74), nivolumab (OR: 0.38, 95% CI: 0.24-0.62) and atezolizumab (OR: 0.21, 95% CI: 0.14-0.33). The odds of treatment discontinuation without progression were similar between nivolumab and atezolizumab (OR: 1.20, 95% CI: 0.73-2.00), and between pembrolizumab and nivolumab (OR: 1.35, 95% CI: 0.83-2.17), but was higher with atezolizumab compared to nivolumab (OR: 2.56, 95% CI: 1.29-5.00). Pembrolizumab was associated with higher OR of immune-related adverse events (IRAEs) compared to nivolumab (OR: 2.12, 95% CI: 1.49-3.03) and atezolizumab (OR: 1.63, 95% CI: 1.09-2.43).

Conclusions: Pembrolizumab, nivolumab, and atezolizumab have similar efficacy. Avelumab appears less efficacious. Safety and tolerability seem better with avelumab, but worse with atezolizumab and pembrolizumab.

Impact of age on outcomes and symptoms in patients with advanced gastroesophageal cancer (GEC)

193

Background: Although age is a non-modifiable risk factor for most cancers, alone it is not very helpful in deciding on the best treatment for patients. Insufficient data exist in the oldest old ( > 75 years) compared to young-old (65-75 years) and to younger ( < 65 years) patients with de novo metastatic GEC regarding which factors influence response and outcomes. Methods: We retrospectively assessed all patients with de novo metastatic GEC seen from 2006-2015 at the Princess Margaret Cancer Center in Toronto-Ontario, Canada. We used Kaplan-Meier plots and Cox proportional hazards analyses to examine factors associated with progression-free survival (PFS) and overall survival (OS). To examine patient-reported outcomes we used the Edmonton Symptom Assessment System (ESAS) in the first six months of therapy using cross-sectional and longitudinal analyses. Results: A total of 580 de novo metastatic GEC patients were seen between 2006 and 2015. Of these (14%) were oldest old, (31%) were young-old (age 65-75) and 54% were younger ( < 65 years). Most patients (67-80%) were male. Median OS for the entire cohort was 9.1 mo. (95% confidence interval (CI) 8.0 – 10.1); the shortest OS was in the oldest old group at 4.5 mo. compared to 8.7 mo. in young-old and 9.8 mo. in younger group, p < 0.001. PFS was also significantly different among the age groups (4.4 mo., 6.1 mo., and 6.5 mo., respectively), p = 0.0145. In a multivariate model predictors for OS were age (young-old group), number of metastasis, and Eastern Cooperative Oncology Group (ECOG) performance scale (PS). Similar predictors were found for PFS; however, age was not a significant factor. Of the 55 patients who provided ESAS data, 58% were < 65 and 42% were age≥ 65. The most common symptoms at presentation were fatigue, appetite, and well-being. There were no differences by age group (all p > 0.05). Conclusions: Patients age > 75 have poorer OS compared to younger age groups but PFS does not differ, suggesting similar benefits with treatment in appropriately selected older adults with advanced GEC. Symptom profiles were similar with age. Further comprehensive care is needed for older patients with advanced GEC to improve their survival.

Macrocytosis as a predictor of response to capecitabine in solid cancers: A meta-analysis

e13080

Background: Capecitabine is an effective oral chemotherapy that is widely used in a number of solid cancers both as monotherapy or in combination with other anti-cancer drugs. It has been suggested that mean corpuscular volume (MCV) is associated with response to capecitabine. Methods: We searched PubMed for studies exploring the association between capecitabine and macrocytosis or MCV. We extracted the hazard ratios (HR) reporting progression-free (PFS) or overall survival (OS) data when comparing macrocytosis to normal/low MCV. If HR were not directly reported, we estimated them from survival plots using the Parmar method. HR were then pooled in a meta-analysis using generic inverse variance and random effects modeling. Results: Among the 13 identified studies, five were eligible for analysis, comprising a total of 446 patients. One study was a randomized trial and four were retrospective cohort studies. Mean patient age was 53 and cancer sites included breast (n = 226; 50%), colon (n = 131; 29 %) and stomach (n = 89; 19%). Capecitabine was used in combination with other drugs in 64% of patients. There was no association between macrocytosis and PFS (HR 0.91, 0.60-1.38, p = 0.65). Among the 3 studies reporting OS data, there was a significant negative association between macrocytosis and worse OS (HR 1.79, 1.38-2.34, p < 0.001). Conclusions: Macrocytosis in patients treated with Capecitabine was found to have no impact on PFS, but was associated with an inferior OS. This finding suggests that macrocytosis is more likely to be a prognostic factor rather than a predictive biomarker of response to capecitabine.

Comparative efficacy, safety, and tolerability of immune checkpoint inhibitors (ICIs) in cancer

e15151

Background: Multiple ICIs have been approved, and in some diseases there is a choice of more than one ICI. The comparative safety, efficacy, and tolerability are not known. Here we report on a network meta-analysis comparing different ICIs targeting PD1 or PDL1. Methods: Randomized trials (RCTs) supporting the registration of a single agent anti-PD1 or anti-PDL1 inhibitors between 2015-2019 were identified. We extracted the hazard ratio (HR) for overall survival (OS) and calculated the odds ratio (OR) for commonly reported safety and tolerability outcomes. We then performed a network meta-analysis including only disease sites in which more than one ICI has been approved. Multiple pair-wise comparisons were then performed. When more than 2 comparisons were available for a pair of ICIs these were pooled into a single estimate. Analyses were performed in Microsoft Excel and RevMan 5.3. Results: Of 16 RCTs included, 10 in non-small-cell lung cancer, 2 in melanoma, 2 in head and neck squamous cell carcinoma and 2 in urothelial cancer. There was a total of 10673 patients in the analysis. Compared to pembrolizumab, efficacy was similar for nivolumab (HR 1.06, 95% CI 0.97-1.16) and for atezolizumab (HR 1.05, 95% CI 0.93-1.20). However, avelumab appeared inferior (HR 1.29, 95% CI 1.07-1.57). Pembrolizumab showed similar odds of serious adverse events (SAEs) as nivolumab (OR 1.12, 95% CI 0.56-2.27) and atezolizumab (OR 1.05, 95% CI 0.55-2.04). However, compared to nivolumab, atezolizumab was associated with more SAEs (OR 2.14, 95% CI 1.47-3.12). Avelumab had the lowest odds of grade 3-4 adverse events compared to pembrolizumab (OR 0.42, 95% CI 0.24-0.74), nivolumab (OR 0.38, 95% CI 0.24-0.62) and atezolizumab (OR 0.21, 95% CI 0.14-0.33). Atezolizumab was associated with more grade 3-4 adverse events than nivolumab (OR 1.84, 95% CI 1.37-2.47). The odds of treatment discontinuation without progression were similar between nivolumab and atezolizumab (OR 1.20, 95% CI 0.73-2.00), but higher with pembrolizumab compared to nivolumab (OR 1.35, 95% CI 0.83-2.17) and atezolizumab (OR 2.56, 95% CI 1.29-5.00). Pembrolizumab was associated with higher OR of immune related adverse events (IRAEs) compared to nivolumab (OR 2.12, 95% CI 1.49-3.03) and atezolizumab (OR 1.63, 95% CI 1.09-2.43), while the OR of IRAEs was almost similar between nivolumab and atezolizumab. Conclusions: Pembrolizumab, nivolumab, and atezolizumab have similar efficacy. Avelumab appears efficacious. Safety and tolerability seem better with avelumab, but worse with atezolizumab and pembrolizumab.

BRCA mutations in metastatic colorectal cancer (mCRC) and response to chemotherapy

235

Background: Mutations in BRCA 1/2 are typically associated with breast, ovarian, pancreatic and prostate cancers. BRCA mutations have been reported in colorectal cancer in sporadic case series. Unlike other cancers, the significance of BRCA mutations in mCRC is not known. We report the prevalence and molecular characteristics associated with BRCA 1/2 mutations in mCRC, and investigate the impact of these mutations on chemotherapy response since both oxaliplatin (OX) and irinotecan (IRI) interfere with DNA repair pathways. Methods: The Ontario-wide Cancer Targeted Nucleic Acid Evaluation (OCTANE) database was queried to identify mCRC patients (pts) harbouring BRCA 1/2 mutations. BRCA 1/2 mutations were detected using panel-based next generation sequencing (NGS) on archival tumour tissue. Clinical and molecular variables were collected, together with treatment outcomes. Results: Of 279 mCRC pts within the OCTANE database as of March 2019, 9 pts with BRCA 1/2 mutations were identified (3.2%): 4 BRCA 1 and 5 BRCA 2 mutations. Each patient had a unique variant with 8/9 missense mutations and 1/9 splicing error. Allele frequency ranged from 0.11 to 0.57. RAS or BRAF mutations were present in 67%. Common co-mutations included TP53 (56%), APC (56%), TSC1 (44%), ROS1 (33%) and ATM(33%). 2 pts were mismatch repair deficient. Median age was 48.5 years (range: 31-69 years), 56% males. 5 pts presented with de novo metastatic disease. First line OX-containing chemotherapy was administered to 4 pts, and IRI to 3 pts. 2 pts did not receive chemotherapy (1 had surgery only post-adjuvant OX, and 1 immunotherapy). Overall response rate (ORR) was 71%, with all pts achieving a partial response or stable disease. The median progression-free survival was 7.5 months (range: 1.8- 31.7 months) and median overall survival 68.5 months (range: 10.5- 68.5 months) respectively. Conclusions: BRCA 1/2 mutations are present in a small subset of mCRC pts. Pts with these mutations tend to be younger at diagnosis. BRCA 1/2 mutations are associated with favourable response to first line chemotherapy. Targeting BRCA 1/2 mutations may broaden treatment options for these patients.