Simultaneous integrated boost for mediastinal lymph node recurrence after radical surgery for esophageal cancer: Interim results from a phase I/II prospective study

Characterization and dosimetric predictors for absolute lymphocyte count changes during neoadjuvant chemoradiotherapy with or without pembrolizumab for esophageal squamous cell carcinoma: an analysis of a prospective cohort

AIM

To characterize the differences of dynamic changes for absolute lymphocyte count (ALC) among esophageal squamous cell carcinoma (ESCC) patients treated with neoadjuvant chemoradiotherapy (nCRT) with or without pembrolizumab, as well as to investigate the clinical and lymphocyte-related organs dosimetric parameters that would impact ALC nadir during nCRT.

MATERIALS AND METHODS

A total of 216 ESCC patients who received nCRT (with pembrolizumab 144; without pembrolizumab: 72) were identified from a prospective cohort. Weekly and 1-month post-nCRT ALC were identified. lymphocyte-related organs at risk (LOARs) were delineated. linear and logistic regression analysis was used to analyze the association between G4 lymphopenia/lymphopenia nadir and clinical/DVHs factors. Receiver-operating characteristic curves were used to derive optimal dosimetric planning constraints. Grade 4 (G4) lymphopenia was defined as ALC < 0.2 × 109/L during nCRT.

RESULTS

G4 lymphopenia was observed in 35 ESCC patients (16.2%) during neoadjuvant treatment. Compared to nCRT alone, the addition of pembrolizumab to nCRT significantly improve lymphopenia recovery in the 1-months after nCRT (p = 0.0003), but the ALC at other time point during nCRT and ALC nadir was comparable between the two groups. A total of 198 patients finally received surgery. Of them, 98 patients archived pCR (49.5%), with 50.4% (68/135 patients) in nCRT with pembrolizumab and 47.6% (30/63) in nCRT alone(p = 0.94), respectively. The mean ALC nadir in the pCR group was significantly higher than those without (p = 0.0003). Multivariable linear and logistic regression analysis indicated that TVB mean dose, TVB V5, TVB V10, TVB V20, mean cardiopulmonary dose, mean ribs dose, mean whole body dose, mean spleen dose, V5, V10, and V20 of spleen dose were significantly associated with developing grade 4 lymphopenia. Dosimetric analysis showed that lymphocyte-sparing photon or proton irradiation was feasible while did not compromise clinically acceptable objectives.

CONCLUSION

The addition of pembrolizumab to nCRT improved lymphopenia recovery for ESCC after trimodality therapy. ALC nadir was significantly associated with pCR and RFS after nCRT. Sparing of LOARs using advanced radiation techniques might reduce the risk of developing lymphopenia and improve treatment response in the era of immunotherapy.

The addition of pembrolizumab to neoadjuvant chemoradiotherapy did not increase the risk of developing postoperative anastomotic leakage for ESCC: an analysis from a prospective cohort

BACKGROUND

To compare the difference of postoperative anastomotic leakage (AL) rate between neoadjuvant chemoradiotherapy (NCRT) with pembrolizumab and NCRT group, and investigate the risk factors of developing AL for locally advanced esophageal squamous cell cancer (ESCC).

MATERIALS AND METHODS

The GF was contoured on the pretreatment planning computed tomography and dosimetric parameters were retrospectively calculated. Univariate and multivariate logistic regression analysis was performed to determine the independent risk predictors for the entire cohort. A nomogram risk prediction model for postoperative AL was established.

RESULTS

A total of 160 ESCC patients were included for analysis. Of them, 112 were treated with NCRT with pembrolizumab and 44 patients with NCRT. Seventeen (10.6%) patients experienced postoperative AL with a rate of 10.7% (12/112) in NCRT with pembrolizumab and 11.4% (5/44) in NCRT group. For the entire cohort, mean, D50, Dmax, V5, V10 and V20 GF dose were statistically higher in those with AL (all p < 0.05). Multivariate logistic regression analysis indicated that tumor length (p = 0.012), volume of GF (p = 0.003) and mean dose of GF (p = 0.007) were independently predictors for postoperative AL. Using receiver operating characteristics analysis, the mean dose limit on the GF was defined as 14 Gy.

CONCLUSION

Based on our prospective database, no significant difference of developing AL were observed between NCRT with pembrolizumab and NCRT group. We established an individualized nomograms based on mean GF dose combined with clinical indicators to predict AL in the early postoperative period.

A machine learning approach using 18F-FDG PET and enhanced CT scan-based radiomics combined with clinical model to predict pathological complete response in ESCC patients after neoadjuvant chemoradiotherapy and anti-PD-1 inhibitors

Background

We aim to evaluate the value of an integrated multimodal radiomics with machine learning model to predict the pathological complete response (pCR) of primary tumor in a prospective cohort of esophageal squamous cell carcinoma (ESCC) treated with neoadjuvant chemoradiotherapy (nCRT) and anti-PD-1 inhibitors.

Materials and methods

Clinical information of 126 ESCC patients were included for analysis. Radiomics features were extracted from 18F-FDG PET and enhanced plan CT images. Four machine learning algorithms, including SVM (Support Vector Machine), Random Forest (RF), and eXtreme Gradient Boosting (XGB) and logistic regression (LR), were applied using k-fold cross-validation to predict pCR after nCRT. The predictive ability of the models was assessed using receiver operating characteristics (ROC) curve analysis.

Results

A total of 842 features were extracted. Among the four machine learning algorithms, SVM achieved the most promising performance on the test set for PET(AUC:0.775), CT (AUC:0.710) and clinical model (AUC:0.722). For all combinations of various modalities-based models, the combination model of 18 F-FDG PET, CT and clinical features with SVM machine learning had the highest AUC of 0.852 in the test set when compared to single-modality models in various algorithms. The other combined models had AUC ranged 0.716 to 0.775.

Conclusion

Machine learning models utilizing radiomics features from 18F-FDG PET and enhanced plan CT exhibit promising performance in predicting pCR in ESCC after nCRT and anti-PD-1 inhibitors. The fusion of features from multiple modalities radiomics and clinical features enhances the better predictive performance compared to using a single modality alone.

Simultaneous integrated boost for mediastinal lymph node recurrence after radical surgery for esophageal cancer: Interim results from a phase I/II prospective study

Background

This was a single institute, phase I/II study of salvage chemoradiotherapy (CRT) with simultaneous integrated boost in patients with mediastinal lymph node (LN) recurrence after esophagectomy.

Methods

Patients who presented with a clinical diagnosis of ≤5 mediastinal LN recurrence received three consecutive levels of radiotherapy dose for the recurrences. Level 1: 58.8 Gy/2.1 Gy/28 fractions, Level 2: 64.4 Gy/2.3 Gy/28 fractions and Level 3: 70 Gy/2.5 Gy/28 fractions.

Results

A total of 17 patients (10 patients in phase I and 7 patients in phase II) were enrolled in the present study between June 2019 and July 2020. The median duration from surgery to initial recurrence was four months (range: 3–43 months). The most common site of recurrence according to JES was 106recR, accounting for 35%. Dose‐limiting toxicity was not observed during three‐month follow‐up after completion of irradiation. The most common hematological toxicities were leukocytopenia and anemia. The most common nonhematological toxicity was esophagitis. The ORR according to RECIST was 58.8% (CR: seven patients; PR: three patients). With a median follow‐up of 15 months (95% CI: 7–16 months), all patients were still alive. Among them, two patients who received a level 1 dose and one patient who received a level III dose developed multiple lung metastases after salvage CRT, and another patient who received a level 1 dose developed an out‐of‐field recurrence in the left cervical lymph node area. Another patient who received a level III dose developed chest wall recurrence after salvage CRT.

Conclusions

The regimen of salvage CRT using the simultaneous integrated boost (SIB) technique (70 Gy/2.5 Gy/28F) for mediastinal lymph node recurrence in ESCC patients after esophagectomy is feasible and well tolerated.