Impact of the new government-involved noninvasive prenatal testing certification system on the awareness of pregnant women about noninvasive prenatal testing in Japan.

AIM: In Japan, noninvasive prenatal testing (NIPT) has been performed by facilities accredited by the Japanese Society of Obstetrics and Gynecology since 2013. However, since 2016, with the implementation of NIPT, which can only be performed by blood sampling, non-obstetricians have been involved in prenatal testing. Therefore, in July 2022, a new government-involved NIPT certification system based on Health Sciences Council guidelines was introduced to ensure access to prenatal testing information for pregnant women. METHODS: This survey was conducted in February 2023 and was the first survey after the certification system implementation. We conducted a web-based survey of 1227 pregnant women and nursing mothers who underwent NIPT after July 2022 to evaluate their experiences. RESULTS: Respondents were categorized by certification status as certified (C: 56%), non-certified (non-C: 23%), or uncertain (Q: 20%). The C group with a higher mean age at examination (35.0 ± 4.5 years) paid lower examination fees, received longer pre- and post-examination explanations, and underwent more weekday examinations (80%) than the other groups. Most respondents, 67%, 48%, and 53% in the C, non-C, and Q groups, respectively (p < 0.0001), stated that "NIPT needs to be regulated by the government or academic societies." The non-C group was more likely to say, "Insufficient post-test explanations at the laboratory made me more anxious," than the other groups when the testing results were non-negative (p = 0.015). CONCLUSIONS: Despite government regulation, some pregnant women choose convenience over certified facilities, risking inadequate care. The government should ensure that NIPT is a safe option for all pregnant women.

Lynch syndrome screening in patients with young-onset extra-colorectal Lynch syndrome-associated cancers.

BACKGROUND: Lynch syndrome (LS) is a hereditary cancer syndrome caused by pathogenic germline variants in mismatch repair (MMR) genes, which predisposes to various types of cancers showing deficient MMR (dMMR). Identification of LS probands is crucial to reduce cancer-related deaths in affected families. Although universal screening is recommended for colorectal and endometrial cancers, and age-restricted screening is proposed as an alternative, LS screening covering a broader spectrum of cancer types is needed. In the current study, we elucidated the rate of dMMR tumors and evaluated the outcome of LS screening in young-onset extra-colorectal LS-associated cancers. METHODS: Immunohistochemistry for MMR proteins were retrospectively performed in a total of 309 tissue samples of endometrial, non-mucinous ovarian, gastric, urothelial, pancreatic, biliary tract, and adrenal cancers in patients < 50 years of age. Clinicopathological information and the results of genetic testing were obtained from medical charts. RESULTS: There were 24 dMMR tumors (7.8%) including 18 endometrial, three ovarian, two urothelial, and one gastric cancer. Co-occurrence of colorectal cancer and family history of LS-associated cancers was significantly enriched in patients with dMMR tumors. Among the 16 patients with dMMR tumors who were informed of the immunohistochemistry results, five with endometrial and one with urothelial cancer were diagnosed as LS with positive pathogenic variants in MMR genes. CONCLUSIONS: We report the outcome of immunohistochemistry for MMR proteins performed in multiple types of young-onset extra-colorectal LS-associated cancers. Our study demonstrates the feasibility of a comprehensive LS screening program incorporating young-onset patients with various types of extra-colorectal LS-associated cancers.

Moderate cryptoxanthin intake correlates with maintenance of a proper PINT index in a general Japanese population.

INTRODUCTION: Small fibre neuropathy (SFN) is an early manifestation of diabetic polyneuropathy. Although oxidative stress, inflammation and change of intestinal bacterial population are assumed to be their pathogenesis, the effects of dietary nutrition have not been evaluated. The relationship between dietary nutrition intake and pain sensation was evaluated in the Japanese population. METHODS: We conducted the Iwaki project, a population-based study recruiting 1,028 individuals, in 2018. The relationships between the pain threshold from intraepidermal electrical stimulation (PINT) and the amount of dietary nutrition evaluated by a brief-type self-administered diet history questionnaire were examined. The odds ratio was further explored after categorizing subjects based on low (< 63.7 µg/day), intermediate (63.7-159.2 µg/day), and high cryptoxanthin levels (> 159.2 µg/day). RESULTS: Univariate linear regression analyses showed significant correlations between PINT and cryptoxanthin intake even after adjustments for other nutritional intakes (ß = 0.107, p < 0.01). Multivariate logistic regression analysis revealed low and high cryptoxanthin intake as significant risk factors for abnormal PINT (≥ 0.20 mA). Multivariate linear regression analyses showed significant correlations between PINT and cryptoxanthin intake levels after adjustment for other clinically PINT-related factors (ß = 0.09, p < 0.01). CONCLUSIONS: Adequate intake of cryptoxanthin is recommended to maintain the pain threshold in the Japanese population.

Differentiating multiple sclerosis and neuromyelitis optica spectrum disorders through pontine trigeminal nerve lesions: A comparative MRI study.

PURPOSE: Multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) are two major demyelinating diseases affecting the central nervous system (CNS). The objective of this study is to evaluate the prevalence of pontine trigeminal nerve lesions in patients diagnosed with MS and NMOSD using MRI. METHODS: This retrospective study included patients diagnosed with MS or NMOSD between July 2018 and July 2023. MS patients were clinically diagnosed using the 2017 McDonald criteria, while NMOSD patients were those who met the 2015 International Panel for NMO Diagnosis (IPND) criteria and were positive for Aquaporin-4 Antibody (AQP4-Ab). RESULTS: The study included a total of 90 patients, with 45 diagnosed with MS and another 45 with NMOSD. Pontine trigeminal nerve lesions were observed in both MS and NMOSD, but were more prevalent in MS patients (20 % vs. 2 %, p = 0.008). Root entry zone (REZ) lesions were found in 4 of 45 MS patients, accounting for 9 % (95 % CI: 3 %-17 %), and were absent in the NMOSD group; however, there was no significant difference between the two groups (p = 0.12). Of the MS patients with pontine trigeminal nerve lesions, 6 out of 9 (63 %; 95 % CI, 36 %-98 %) exhibited bilateral lesions, which was significantly more prevalent compared to the NMOSD group (13 % vs. 0 %, p = 0.03). CONCLUSIONS: The presence of pontine trigeminal nerve lesions, particularly when bilateral, are significantly more prevalent in MS patients than in those with NMOSD, suggesting their utility as a distinctive marker and potential diagnostic indicator specifically for MS.

Novel insight into nicotinamide adenine dinucleotide and related metabolites in cancer patients undergoing surgery.

Nicotinamide adenine dinucleotide (NAD +) plays a pivotal role in numerous cellular functions. Reduced NAD + levels are postulated to be associated with cancer. As interest in understanding NAD + dynamics in cancer patients with therapeutic applications in mind grows, there remains a shortage of comprehensive data. This study delves into NAD + dynamics in patients undergoing surgery for different digestive system cancers. This prospective study enrolled 99 patients with eight different cancers. Fasting blood samples were obtained during the perioperative period. The concentrations of NAD + , nicotinamide mononucleotide (NMN), and nicotinamide riboside were analyzed using tandem mass spectrometry. After erythrocyte volume adjustment, NAD + remained relatively stable after surgery. Meanwhile, NMN decreased the day after surgery and displayed a recovery trend. Interestingly, liver and pancreatic cancer patients exhibited poor postoperative NMN recovery, suggesting a potential cancer type-specific influence on NAD + metabolism. This study illuminated the behavior of NAD + in surgically treated cancer patients. We identified which cancer types have particularly low levels and at what point depletion occurs during the perioperative period. These insights suggest the need for personalized NAD + supplementation strategies, calibrated to individual patient needs and treatment timelines. Clinical trial registration jRCT1020210066.

Combination immunohistochemistry for CK5/6, p63, GATA6, and HNF4a predicts clinical outcome in treatment-naïve pancreatic ductal adenocarcinoma.

Although sequence-based studies show that basal-like features lead to worse prognosis and chemotherapy-resistance compared to the classical subtype in advanced pancreatic ductal adenocarcinoma (PDAC), a surrogate biomarker distinguishing between these subtypes in routine diagnostic practice remains to be identified. We aimed to evaluate the utility of immunohistochemistry (IHC) expression subtypes generated by unsupervised hierarchical clustering based on staining scores of four markers (CK5/6, p63, GATA6, HNF4a) applied to endoscopic ultrasound-guided fine needle aspiration biopsy (EUS-FNAB) materials. EUS-FNAB materials taken from 190 treatment-naïve advanced PDAC patients were analyzed, and three IHC patterns were established (Classical, Transitional, and Basal-like pattern). Basal-like pattern (high co-expression of CK5/6 and p63 with low expression of GATA6 and HNF4a) was significantly associated with squamous differentiation histology (p < 0.001) and demonstrated the worst overall survival among our cohort (p = 0.004). IHC expression subtype (Transitional, Basal vs Classical) was an independent poor prognosticator in multivariate analysis [HR 1.58 (95% CI 1.01-2.38), p = 0.047]. Furthermore, CK5/6 expression was an independent poor prognostic factor in histological glandular type PDAC [HR 2.82 (95% CI 1.31-6.08), p = 0.008]. Our results suggest that IHC expression patterns successfully predict molecular features indicative of the Basal-like subgroup in advanced PDAC. These results provide the basis for appropriate stratification for therapeutic selection and prognostic estimation of advanced PDAC in a simplified manner.

Iron-Catalyzed C-H Alkylamination of Tyrosine Derivatives.

An efficient method for the direct alkylamination of tyrosine derivatives via iron-catalyzed C-H amination has been developed. The method, using O-benzoyl-N,N-dialkylhydroxylamines as aminating agents, provides various C-amino-functionalized tyrosine derivatives in up to 77% yield. The utility of this method is showcased by its application to the direct introduction of drug molecules into tyrosine, facilitating access to structurally diverse amino-functionalized tyrosine derivatives.

Metabolic Tug-of-War between Glycolysis and Translation Revealed by Biochemical Reconstitution.

Inside cells, various biological systems work cooperatively for homeostasis and self-replication. These systems do not work independently as they compete for shared elements like ATP and NADH. However, it has been believed that such competition is not a problem in codependent biological systems such as the energy-supplying glycolysis and the energy-consuming translation system. In this study, we biochemically reconstituted the coupling system of glycolysis and translation using purified elements and found that the competition for ATP between glycolysis and protein synthesis interferes with their coupling. Both experiments and simulations revealed that this interference is derived from a metabolic tug-of-war between glycolysis and translation based on their reaction rates, which changes the threshold of the initial substrate concentration for the success coupling. By the metabolic tug-of-war, translation energized by strong glycolysis is facilitated by an exogenous ATPase, which normally inhibits translation. These findings provide chemical insights into the mechanism of competition among biological systems in living cells and provide a framework for the construction of synthetic metabolism in vitro.

Tryptophan metabolism and small fibre neuropathy: a correlation study.

Small nerve fibres located in the epidermis sense pain. Dysfunction of these fibres decreases the pain threshold known as small fibre neuropathy. Diabetes mellitus is accompanied by metabolic changes other than glucose, synergistically eliciting small fibre neuropathy. These findings suggest that various metabolic changes may be involved in small fibre neuropathy. Herein, we explored the correlation between pain sensation and changes in plasma metabolites in healthy Japanese subjects. The pain threshold evaluated from the intraepidermal electrical stimulation was used to quantify pain sensation in a total of 1021 individuals in the 2017 Iwaki Health Promotion Project. Participants with a pain threshold evaluated from the intraepidermal electrical stimulation index <0.20 mA were categorized into the pain threshold evaluated from the intraepidermal electrical stimulation index-low group (n = 751); otherwise, they were categorized into the pain threshold evaluated from the intraepidermal electrical stimulation index-high group (n = 270). Metabolome analysis of plasma was conducted using capillary electrophoresis time-of-flight mass spectrometry. The metabolite set enrichment analysis revealed that the metabolism of tryptophan was significantly correlated with the pain threshold evaluated from the intraepidermal electrical stimulation index in all participants (P < 0.05). The normalized level of tryptophan was significantly decreased in participants with a high pain threshold evaluated from the intraepidermal electrical stimulation index. In addition to univariate linear regression analyses, the correlation between tryptophan concentration and the pain threshold evaluated from the intraepidermal electrical stimulation index remained significant after adjustment for multiple factors (ß = -0.07615, P < 0.05). These findings indicate that specific metabolic changes are involved in the deterioration of pain thresholds. Here, we show that abnormal tryptophan metabolism is significantly correlated with an elevated pain threshold evaluated from the intraepidermal electrical stimulation index in the Japanese population. This correlation provides insight into the pathology and clinical application of small fibre neuropathy.

Correction: 2-cyanopyridine derivatives enable N-terminal cysteine bioconjugation and peptide bond cleavage of glutathione under aqueous and mild conditions.

[This corrects the article DOI: 10.1039/D4RA00437J.].

Identification of a novel LFNG variant in a Chinese fetus with spondylocostal dysostosis and a systematic review.

Spondylocostal dysostosis (SCDO) encompasses a group of skeletal disorders characterized by multiple segmentation defects in the vertebrae and ribs. SCDO has a complex genetic etiology. This study aimed to analyze and identify pathogenic variants in a fetus with SCDO. Copy number variant sequencing and whole exome sequencing were performed on a Chinese fetus with SCDO, followed by bioinformatics analyses, in vitro functional assays and a systematic review on the reported SCDO cases with LFNG pathogenic variants. Ultrasound examinations in utero exhibited that the fetus had vertebral malformation, scoliosis and tethered cord, but rib malformation was not evident. We found a novel homozygous variant (c.1078 C > T, p.R360C) within the last exon of LFNG. The variant was predicted to cause loss of function of LFNG by in silico prediction tools, which was confirmed by an in vitro assay of LFNG enzyme activity. The systematic review listed a total of 20 variants of LFNG in SCDO. The mutational spectrum spans across all exons of LFNG except the last one. This study reported the first Chinese case of LFNG-related SCDO, revealing the prenatal phenotypes and expanding the mutational spectrum of the disorder.

Comparing Three Different Anti-Programmed Death-Ligand 1 Antibodies in Immunohistochemical Evaluation of Combined Chemoimmunotherapy Response in Patients With NSCLC: A Prospective Study.

Introduction: Multiple programmed death-ligand 1 (PD-L1) immunohistochemistry assays performed using different antibodies including DAKO 22C3, DAKO 28-8, and Ventana SP142 PD-L1-predictive markers for response to various immune checkpoint inhibitors in NSCLC-have been approved in several countries. The differences in multiple PD-L1 immunohistochemistry assay results in predicting the therapeutic response to combined chemoimmunotherapy in patients with NSCLC remain unclear. Methods: In this multicenter prospective observational study, we monitored 70 patients with advanced NSCLC treated with combined chemoimmunotherapy at 10 institutions in Japan. The expression of PD-L1 in pretreatment tumors was evaluated using the 22C3, 28-8, and SP142 assays in all patients. Results: The PD-L1 level in tumor cells determined using the 22C3 assay was the highest among the three assays performed with different antibodies. According to the 22C3 assay results, the PD-L1 tumor proportion score greater than or equal to 50% group had a significantly longer progression-free survival period than the PD-L1 tumor proportion score less than 50% group. Nevertheless, the other assays did not reveal remarkable differences in the objective response rate or progression-free survival. Conclusions: In our study, PD-L1 expression determined using the 22C3 assay was more correlated with the therapeutic response of patients with NSCLC treated with combined chemoimmunotherapy than that determined using the 28-8 and SP142 assays. Therefore, the 22C3 assay may be useful for clinical decision-making for patients with NSCLC treated with combined chemoimmunotherapy. Trial registration number: UMIN 000043958.

Manual on the proper use of the 211At-labeled PSMA ligand ([211At]PSMA-5) for clinical trials of targeted alpha therapy (1st edition).

Recently, an astatine-labeled prostate-specific membrane antigen (PSMA) ligand ([211At]PSMA-5) has been developed for the targeted alpha therapy of patients with prostate cancer. This manual delineates its physicochemical characteristics to assist healthcare professionals in understanding the α-ray-emitting drug of [211At]PSMA-5 when administered to patients. The safety considerations regarding the handling and use of this drug in clinical trials are outlined, based on the proper usage manual of previous studies. The dose limits, as defined by the guidelines of the International Commission on Radiological Protection (ICRP) and the International Atomic Energy Agency (IAEA), are assessed for patients' caregivers and the general public. According to the calculations provided in this manual, clinical trials involving [211At]PSMA-5 can be safely conducted for these populations even if patients are released after its administration. Moreover, this manual provides comprehensive guidance on the handling of [211At]PSMA-5 for healthcare facilities, and compiles a list of precautionary measures to be distributed among patients and their caregivers. While this manual was created by a research team supported by Ministry of Health, Labour, and Welfare in Japan and approved by Japanese Society of Nuclear Medicine, its applicability extends to healthcare providers in other countries. This manual aims to facilitate conducting clinical trials using [211At]PSMA-5 in patients with prostate cancer.

Difficulties in disclosing secondary findings by facilities performing comprehensive germline genetic testing for rare diseases in Japan.

In Japan, a limited number of laboratories perform comprehensive genetic testing for rare diseases; this study investigated the attitudes of these laboratories toward the disclosure of secondary finding (SF). Following a preliminary survey, we identified laboratories conducting comprehensive genetic testing for participation. Subsequently, an online survey involving 20 selected facilities was conducted. The response rate was 80% (16/20). Of the 14 facilities, 71.4% had SFs. While 42.9% of them had a policy to disclose SFs with clinical utility, only 14.3% actively searched for actionable variants that could be included in the American College of Medical Genetics and Genomics list. Japan was less enthusiastic than the USA regarding SF disclosure. With regard to the reasons for not disclosing SFs, the factors "the thought that participants may have a low desire for SFs" and "uncertainty regarding their wish" were considered more important than in the USA. A content analysis of what was sought as a solution to this difficulty revealed a need to improve databases on pathogenicity and actionability and collect public thoughts on the issue. The factor "to promote entry in research" was not considered a critical reason for disclosing SFs, indicating that the thirst for information was not possibly due to anxiety but rather due to scientific interest. Japanese medical professionals may not be confident that society requires the disclosure of SFs. To improve the environment, it is necessary to survey the public regarding their thoughts on SF disclosure and discuss this issue in society.

Follicular dendritic cell sarcoma arising from the lymph node of the pancreatic head: a case report with literature review.

A 72-year-old man was referred to our hospital for the examination of a pancreatic head mass. Abdominal computed tomography revealed a contrasted 8-cm-diameter tumor extending from the dorsal pancreatic head to the porta hepatis. The preoperative diagnosis was challenging due to the absence of specific imaging findings and the inability to perform a biopsy. Positron emission tomography/computed tomography and diffusion-weighted imaging suggested a malignant tumor originating from the organs surrounding the pancreatic head. Subtotal stomach-preserving pancreaticoduodenectomy with regional lymph node dissection was performed, as dissection from the pancreatic head proved unfeasible. Pathological examination identified the tumor as an enlarged lymph node consisting of pleomorphic large cells forming clusters, positive for follicular dendritic cell markers cluster of differentiation (CD) 21 and CD23. No evidence of tumor capsule infiltration, other organ infiltration, or metastasis to other lymph nodes was observed. The final diagnosis was nodal follicular dendritic cell sarcoma (FDCS) originating from the pancreatic head lymph nodes. No recurrence occurred at 3 years postoperatively with no postoperative treatment. Intraperitoneal nodal FDCS is extremely rare, and occasionally, it can lead to postoperative recurrence and progression. It is crucial to differentiate neoplastic lymph node enlargement around the pancreatic head from nodal FDCS.

Efficacy and Safety of Docetaxel plus Ramucirumab for Patients with Pretreated Advanced or Recurrent Non-small Cell Lung Cancer: Focus on Older Patients.

BACKGROUND: Combination therapy with docetaxel (DTX) and ramucirumab (RAM) has been used as a second-line treatment for advanced or recurrent lung cancer. However, there is insufficient evidence regarding the safety of angiogenesis inhibitors in older patients. OBJECTIVE: This multicenter retrospective study aimed to investigate the efficacy and safety of second-line treatment regimens in older patients with advanced or recurrent non-small cell lung cancer (NSCLC). PATIENTS AND METHODS: We retrospectively analyzed 145 patients aged ≥ 70 years with advanced or recurrent NSCLC treated with second-line chemotherapy after platinum-based therapy between April 1, 2016, and March 31, 2021. Patients were subdivided into the DTX + RAM (n = 38) and single-agent (n = 107) groups. RESULTS: The median time to treatment failure was 6.3 months (95% confidence interval [CI] 3.6-9.6) in the DTX + RAM group and 2.3 months (95% CI 1.7-3.0) in the single-agent group (p < 0.01). The median overall survival was 15.9 months (95% CI 12.3-Not Achieved) in the DTX + RAM group and 9.4 months (95% CI 6.9-15.1) in the single-agent group (p = 0.01). Grade ≥ 3 adverse events frequency was not significantly different between the two groups, except for edema. Patients in the DTX + RAM group who did not discontinue treatment owing to adverse events exhibited the most favorable prognosis. CONCLUSIONS: These findings suggest that the DTX + RAM combination is an effective second-line therapy for older patients with advanced or recurrent NSCLC, offering favorable efficacy without treatment discontinuation owing to adverse events.

Corrugator Muscle Activity Associated with Pressure Pain in Adults with Neck/Shoulder Pain.

Background and Objectives: No studies have reported corrugator muscle activity associated with pain in people with pain. This study aimed to develop an objective pain assessment method using corrugator muscle activity with pressure pain stimulation to the skeletal muscle. Methods: Participants were 20 adults (a mean ± SD age of 22.0 ± 3.1 years) with chronic neck/shoulder pain. Surface electromyography (sEMG) of corrugator muscle activity at rest (baseline) and without and with pressure pain stimulation applied to the most painful tender point in the shoulder was recorded. Participants evaluated the intensity of the neck/shoulder pain and the sensory and affective components of pain with pressure stimulation using a visual analogue scale (VAS). The percentages of integrated sEMG (% corrugator activity) without and with pressure pain stimulation to the baseline integrated sEMG were compared, and the relationships between the % corrugator activity and the sensory and affective components of pain VAS scores were evaluated. Results: Without pressure stimulation, an increase in corrugator muscle activity due to chronic neck/shoulder pain was not observed. The % corrugator activity with pressure pain stimulation was significantly higher than that without stimulation (p < 0.01). A significant positive correlation between corrugator muscle activity and the affective components of pain VAS scores with pressure stimulation was found (ρ = 0.465, p = 0.039) and a tendency of positive correlation was found for the sensory component of pain VAS scores (ρ = 0.423, p = 0.063). Conclusions: The increase in corrugator muscle activity with pressure pain stimulation to the tender point in adults with chronic neck/shoulder pain was observed, although increased corrugator muscle activity resulting from the chronic neck/shoulder pain was not. These findings suggest that corrugator muscle activity with pressure pain stimulation can be a useful objective indication for tender point sensitivity assessment in the skeletal muscle with pain.

Impact of the response to platinum-based chemotherapy on the second-line immune checkpoint inhibitor monotherapy in non-small cell lung cancer with PD-L1 expression ≤49%: a multicenter retrospective study.

Introduction: The efficacy of second-line immune checkpoint inhibitor (ICI) therapy is limited in non-small cell lung cancer (NSCLC) patients with ≤ 49% PD-L1 expression. Although chemoimmunotherapy is a promising strategy, platinum-based chemotherapy followed by ICI monotherapy is often used to avoid synergistic adverse events. However, predictors of the efficacy of ICI monotherapy after platinum-based chemotherapy in NSCLC with ≤ 49% PD-L1 expression remain scarce. Methods: This multicenter retrospective study evaluated 54 advanced or recurrent NSCLC patients with ≤ 49% PD-L1 expression who were treated with second-line ICI monotherapy following disease progression on first-line platinum-based chemotherapy at nine hospitals in Japan. The impact of response to platinum-based chemotherapy on the efficacy of subsequent ICI monotherapy was investigated. Results: The response to first-line platinum-based chemotherapy was divided into two groups: the non-progressive disease (PD) group, which included patients who did not experience disease progression after four cycles of chemotherapy, and the PD group, which included patients who showed initial PD or could not maintain disease control during the four cycles of chemotherapy and switched to second-line ICI monotherapy. Among the 54 patients, 32 and 22 were classified into the non-PD and PD groups, respectively. The non-PD group showed better response rates (p = 0.038) and longer overall survival (OS) with ICI monotherapy (p = 0.023) than the PD group. Multivariate analysis identified that maintaining a non-PD status after four cycles of chemotherapy was an independent prognostic factor for ICI monotherapy (p = 0.046). Moreover, patients with a modified Glasgow Prognostic Score (mGPS) of 0 showed a tendency for longer OS with ICI monotherapy (p = 0.079), and there was a significant correlation between maintaining non-PD after four cycles of chemotherapy and an mGPS of 0 (p = 0.045). Conclusion: Maintaining a non-PD status after four cycles of platinum-based chemotherapy was a predictor of OS after second-line ICI monotherapy. These findings will help physicians select the most suitable treatment option for NSCLC patients who were treated with platinum-based chemotherapy and switched to second-line treatment. Those who experienced early PD during platinum-based chemotherapy should not be treated with ICI monotherapy in the second-line setting.