Neoadjuvant radiotherapy/chemoradiotherapy in locally advanced non-small cell lung cancer

Impacts of neoadjuvant therapy on the number of dissected lymph nodes in esophagogastric junction cancer patients

BACKGROUND

Neoadjuvant therapy favors the prognosis of various cancers, including esophagogastric junction cancer (EGC). However, the impacts of neoadjuvant therapy on the number of dissected lymph nodes (LNs) have not yet been evaluated in EGC.

METHODS

We selected EGC patients from the Surveillance, Epidemiology, and End Results (SEER) database (2006-2017). The optimal number of resected LNs was determined using X-tile software. Overall survival (OS) curves were plotted with the Kaplan-Meier method. Prognostic factors were evaluated using univariate and multivariate COX regression analyses.

RESULTS

Neoadjuvant radiotherapy significantly decreased the mean number of LN examination compared to the mean number of patients without neoadjuvant therapy (12.2 vs. 17.5, P = 0.003). The mean LN number of patients with neoadjuvant chemoradiotherapy was 16.3, which was also statistically lower than 17.5 (P = 0.001). In contrast, neoadjuvant chemotherapy caused a significant increase in the number of dissected LNs (21.0, P < 0.001). For patients with neoadjuvant chemotherapy, the optimal cutoff value was 19. Patients with > 19 LNs had a better prognosis than those with 1-19 LNs (P < 0.05). For patients with neoadjuvant chemoradiotherapy, the optimal cutoff value was 9. Patients with  > 9 LNs had a better prognosis than those with 1-9 LNs (P < 0.05).

CONCLUSIONS

Neoadjuvant radiotherapy and chemoradiotherapy decreased the number of dissected LNs, while neoadjuvant chemotherapy increased it in EGC patients. Hence, at least 10 LNs should be dissected for neoadjuvant chemoradiotherapy and 20 for neoadjuvant chemotherapy, which could be applied in clinical practice.

An efficient rectangular optimization method for sparse orthogonal collimator based small animal irradiation

Objective.Intensity-modulated radiotherapy (IMRT) is widely used in clinical radiotherapy, treating varying malignancies with conformal doses. As the test field for clinical translation, preclinical small animal experiments need to mimic the human radiotherapy condition, including IMRT. However, small animal IMRT is a systematic challenge due to the lack of corresponding hardware and software for miniaturized targets.Approach.The sparse orthogonal collimators (SOC) based on the direct rectangular aperture optimization (RAO) substantially simplified the hardware for miniaturization. This study investigates and evaluates a significantly improved RAO algorithm for complex mouse irradiation using SOC. Because the Kronecker product representation of the rectangular aperture is the main limitation of the computational performance, we reformulated matrix multiplication in the data fidelity term using multiplication with small matrices instead of the Kronecker product of the dose loading matrices. Solving the optimization problem was further accelerated using the Fast Iterative Shrinkage-Thresholding Algorithm (FISTA).Main results.Four mouse cases, including a liver, a brain tumor, a concave U-target, and a complex total marrow irradiation (TMI) case, were included in this study with manually delineated targets and OARs. Seven coplanar-field SOC IMRT (sIMRT) plans were compared with idealistic fluence map based IMRT (iIMRT) plans. For the first three cases with simpler and smaller targets, the differences between sIMRT plans and iIMRT plans in the planning target volumes (PTV) statistics are within 1%. For the TMI case, the sIMRT plans are superior in reducing hot spots (also termedDmax) of PTV, kidneys, lungs, heart, and bowel by 20.5%, 31.5%, 24.67%, 20.13%, and 17.78%, respectively. On average, in four cases in this study, the sIMRT plan conformity is comparable to that of the iIMRT's with lightly increased R50 and Integral Dose by 2.23% and 2.78%.Significance.The significantly improved sIMRT optimization method allows fast plan creation in under 1 min for smaller targets and makes complex TMI planning feasible while achieving comparable dosimetry to idealistic IMRT with fluence map optimization.

CUL4high Lung Adenocarcinomas Are Dependent on the CUL4-p21 Ubiquitin Signaling for Proliferation and Survival

Cullin (CUL) 4A and 4B ubiquitin ligases are often highly accumulated in human malignant neoplasms and are believed to possess oncogenic properties. However, the underlying mechanisms by which CUL4A and CUL4B promote pulmonary tumorigenesis remain largely elusive. This study reports that CUL4A and CUL4B are highly expressed in patients with non-small cell lung cancer (NSCLC), and their high expression is associated with disease progression, chemotherapy resistance, and poor survival in adenocarcinomas. Depletion of CUL4A (CUL4Ak/d) or CUL4B (CUL4Bk/d) leads to cell cycle arrest at G1 and loss of proliferation and viability of NSCLC cells in culture and in a lung cancer xenograft model, suggesting that CUL4A and 4B are oncoproteins required for tumor maintenance of certain NSCLCs. Mechanistically, increased accumulation of the cell cycle-dependent kinase inhibitor p21/Cip1/WAF1 was observed in lung cancer cells on CUL4 silencing. Knockdown of p21 rescued the G1 arrest of CUL4Ak/d or CUL4Bk/d NSCLC cells, and allowed proliferation to resume. These findings reveal that p21 is the primary downstream effector of lung adenocarcinoma dependence on CUL4, highlight the notion that not all substrates respond equally to abrogation of the CUL4 ubiquitin ligase in NSCLCs, and imply that CUL4Ahigh/CUL4Bhigh may serve as a prognostic marker and therapeutic target for patients with NSCLC.

A sparse orthogonal collimator for small animal intensity-modulated radiation therapy. Part II: hardware development and commissioning

PURPOSE

A dose-modulation device for small animal radiotherapy is required to use clinically analogous treatment techniques, which will likely increase the translatability of preclinical research results. Because the clinically used multileaf collimator (MLC) is impractical for miniaturization, we have developed a simpler, better-suited sparse orthogonal collimator (SOC) for delivering small animal intensity-modulated radiation therapy (IMRT) using a rectangular aperture optimization (RAO) treatment planning system.

METHODS

The SOC system was modeled in computer-aided design software and fabricated with machined tungsten leaves and three-dimensional (3D) printed leaf housing. A graphical user interface was developed for controlling and calibrating the SOC leaves, which are driven by Arduino-controlled stepper motors. A Winston-Lutz test was performed to assess mechanical alignment, and abutting field and grid dose patterns were created to analyze intra- and intercalibration leaf positioning error. Leaf transmission and penumbra were measured over the full range of gantry angles and leaf positions, respectively. Three SOC test plans were delivered, and film measurements were compared to the intended dose distributions. The differences in maximum, mean, and minimum, as well as pixelwise absolute dose differences, were compared for each structure, and a gamma analysis was performed for the target structures using criteria of 4% dose difference and 0.3 mm distance to agreement.

RESULTS

The Winston-Lutz test revealed maximum directional offsets between the SOC and primary collimator axes of 0.53 mm at 0° and 0.68 mm over the full 360°. Upper and lower abutting field patterns had maximum dose deviations of 18.8 ± 3.1% and 15.5 ± 2.9%, respectively, and grid patterns showed intra- and intercalibration repeatability of 93% and 91%, respectively. Extremely low midleaf (0.15 ± 0.05%) and interleaf (0.27 ± 0.22%) transmission was measured, with no significant rotational variation. The average penumbra was ~0.8 mm for all leaves at field center, with a range of 0.17 mm for all leaf positions. A highly concave test plan was delivered with a ~ 95% gamma analysis pass rate, and a realistic mouse phantom liver irradiation plan achieved a pass rate of ~98%. A highly complex dose distribution was also created with 551 SOC apertures averaging 2.4 mm in size.

CONCLUSIONS

A sparse orthogonal collimator was developed and commissioned, with promising preliminary dosimetry results. The SOC design, with its limited moving components and high dose-modulation resolution, is ideal for delivering high-quality small animal IMRT with our RAO-based treatment planning system.

Pathologic response after modern radiotherapy for non-small cell lung cancer

In non-small cell lung cancer (NSCLC), pathologic complete response (pCR) following radiotherapy treatment has been shown to be an independent prognostic factor for long-term survival, progression-free survival and locoregional control. PCR is considered a surrogate to therapeutic efficacy, years before survival data are available, and therefore can be used to guide treatment plans and additional therapeutic interventions post-surgical resection. Given the extensive fibrotic changes induced by radiotherapy in the lung, radiological assessment of response can potentially misrepresent pathologic response. The optimal timing for assessment of pathologic response after conventionally fractionated radiotherapy and stereotactic ablative radiotherapy (SABR) remains poorly understood. In this review, we summarize recent literature on pathologic response after radiotherapy for early stage and locally advanced NSCLC, we discuss current controversies around radiobiological considerations, and we present upcoming trials that will provide insight into current knowledge gaps.

Trimodality vs Chemoradiation and Salvage Resection in cN2 Stage IIIA Non-Small Cell Lung Cancer

To determine the overall survival (OS) in patients who underwent planned trimodality therapy (TMT) and those who underwent definitive concurrent chemoradiation (CRT), but later received salvage resection (SR) for stage IIIA (cN2) (AJCC 7th ed.) non-small cell lung cancer. National Cancer Database data set from 2004 to 2014 was queried. TMT was defined as multiagent CRT with dose >45 Gy, followed by lobectomy or pneumonectomy ≤90 days from end of CRT. SR was defined as multiagent CRT with dose >59 Gy and lobectomy or pneumonectomy performed >90 days from CRT completion. Propensity score weighting and propensity score matching methods were used to balance patient and tumor characteristics and to calculate hazard ratios. A total of 2025 (1899 TMT and 126 SR) patients were analyzed. TMT and SR groups shared similar characteristics. Surgery occurred at a median of 41 days (range 1-90) after CRT in the TMT group and 114 days (91-440) in the SR group. The 90-day mortality after surgery was 6.5% for TMT and 5% for SR (P = 0.43). The 3- and 5-year OS were 55.1% and 35.7% for TMT and 51.6% and 45.0% for SR (P = 0.92, 0.68), with no difference across unadjusted cohort and propensity-adjusted cohort. Patients with cN2 stage IIIA non-small cell lung cancer treated in the United States with definitive CRT followed by SR had similar OS as upfront TMT with similar postoperative mortality despite SR occurring >90 days after >59 Gy CRT. SR remains an option for medically appropriate patients after definitive dose CRT.

Long-term effects of neoadjuvant radiotherapy, adjuvant radiotherapy, and chemotherapy-only on survival of locally advanced non-small cell lung Cancer undergoing surgery: a propensity-matched analysis

Background

The optimal timing of radiotherapy (RT) with respect to surgery remains controversial for locally advanced non-small cell lung cancer (LA NSCLC) undergoing surgery and the long-term effect of neoadjuvant RT, adjuvant RT, and chemotherapy-only on survival is unknown.

Methods

A retrospective study with Greedy 5 → 1 Digit propensity score matching technique was performed for locally advanced NSCLC patients identified from the Surveillance, Epidemiology, and End Results (SEER) database during 2004 to 2012. Kaplan-Meier and the log-rank test were conducted to compare NSCLC-specific survival. Cox proportional hazards multivariable regression was performed to assess the impact of different treatment regimens on cancer-specific mortality after adjustment for demographic factors, histology type, tumor grade, tumor size, nodal stage, and extent of resection.

Results

One thousand, two hundred and seventy-eight locally advanced NSCLC patients undergoing surgery were identified after propensity matching. Cox regression analyses showed the risk of cancer-specific mortality is not significantly different among neoadjuvant RT, adjuvant RT, and chemotherapy-only. Subgroup analyses showed that for patients with T1/2 & N2/3, the surgery plus chemotherapy-only group showed markedly higher mortality risk (HR = 1.42, 95%CI:1.10–1.83) than the neoadjuvant RT group. Other risk factors include older age, higher tumor grade, larger tumor size, and greater lymph node involvement.

Conclusions

The findings of this study suggest that the benefit of additional neoadjuvant or adjuvant RT to chemotherapy may be linked to a proper selection of LA NSCLC patients who undergo surgery. The timing of radiotherapy should be decided on the premise of fully considering patients’ condition and the quality of life after treatment.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4900-x) contains supplementary material, which is available to authorized users.

Pneumonectomy for Non-Small Cell Lung Cancer

Lung cancer is the leading cause of cancer deaths and its incidence continues to increase. Emerging therapies as part of a multimodal approach are making more patients eligible for surgical resection. As more surgeons are treating locally advanced non-small cell lung cancer they find themselves recommending pneumonectomy as the surgical component of the multidisciplinary plan. Performing a pneumonectomy is technically demanding and is associated with many potential perioperative comorbidities. With the proper preparation, experience, and attention to perioperative care, pneumonectomy can be carried out safely with excellent outcomes and a good quality of life.

Timing of Surgery after Neoadjuvant Chemoradiation in Locally Advanced Non-Small Cell Lung Cancer

INTRODUCTION

A subset of patients with potentially resectable clinical stage IIIA NSCLC are managed with trimodality therapy. However, little data exist to guide the timing of surgery after neoadjuvant therapy. This study examined whether the time interval between neoadjuvant chemoradiation (NCRT) and surgical resection affects overall survival.

METHODS

Patients with clinical stage IIIA disease (T1-3 N2) NSCLC who underwent NCRT were identified in the National Cancer Data Base (NCDB) between 2004 and 2012 and categorized on the basis of the interval between chemoradiation and surgery (0 to ≤3, >3 to ≤6, >6 to ≤9, and >9 to ≤12 weeks). Other clinical stages were excluded. The Kaplan-Meier method and log-rank tests were used to compare overall survival rates, and a bootstrapped Cox proportional hazards model was used to determine significant contributors to overall survival.

RESULTS

Of the 1623 patients identified, 7.9% underwent an operation 0 to 3 weeks or less after NCRT, 50.5% underwent an operation greater than 3 and less than or equal to 6 weeks after NCRT, 31.9% underwent an operation greater than 6 and less than or equal to 9 weeks after NCRT, and 9.6% underwent an operation greater than 9 and less than or equal to 12 weeks after NCRT. Multivariate survival analysis demonstrated no significant difference in survival in those who underwent an operation within 6 weeks of NCRT. However, significant drops in overall survival were observed in those who had an operation greater than 6 and less than or equal to 9 weeks after NCRT (hazard ratio = 1.33, 95% confidence interval: 1.01-1.76, p = 0.043) and greater than 9 and less than or equal to 12 weeks after NCRT (hazard ratio = 1.44, 95% confidence interval: 1.04-2.01, p = 0.030).

CONCLUSIONS

The findings from this retrospective study suggest that overall survival may be significantly lower in patients with clinical stage IIIA N2 NSCLC who undergo an operation later than 6 weeks after NCRT. These results discourage unnecessary delays in surgery.

The impact of epidermal growth factor receptor mutations on patterns of disease recurrence after chemoradiotherapy for locally advanced non-small cell lung cancer: a literature review and pooled analysis

The purpose of this review was to evaluate the impact of epidermal growth factor receptor (EGFR) mutation status on disease recurrence in patients treated with chemoradiotherapy (CRT) for locally advanced non-small cell lung cancer (NSCLC). A literature search was conducted and a total of three studies were analyzed. There was no significant difference in the objective response rate between the EGFR mutation group and the EGFR wild-type group (odds ratios [OR] 1.46, 95% CI, 0.79-2.70, P = 0.228), and there was no significant difference in the incidence of disease recurrence (OR 1.37, 95% CI, 0.68-2.75, P = 0.379) between the two groups. There were significant difference in the incidence of local/locoregional progression (LP) (OR 0.35, 95% CI, 0.18-0.71, P = 0.003) and distant progression (DP) (OR 2.97, 95% CI, 1.59-5.54, P < 0.001). Brain metastasis (BM) was one of the main recurrence patterns of DP, and the incidence was significantly higher in the EGFR mutant group (OR 2.75, 95% CI, 1.43-5.31, P = 0.003). There were no statistically significant heterogeneities in these pooled analyses. The patterns of recurrence after CRT for locally advanced NSCLC were different according to EGFR mutation status. LP after CRT in patients with EGFR mutation was less frequent, but the high incidence of DP, especially BM, continued to be the major problem. On the other hand, LP continued to be the major problem in EGFR wild-type patients. In multimodality treatment for inoperable locally advanced NSCLC, we may need to consider different treatment strategies according to EGFR mutation status.