Locoregional recurrence after pulmonary sublobar resection of non-small cell lung cancer: can it be reduced by considering cancer cells at the surgical margin?

Clinical outcomes of left upper segmentectomy vs. lobectomy for early non-small-cell lung cancer: a nationwide database study in Japan

PURPOSE

Given that left upper lobe and right upper and middle lobes share a similar anatomy, segmentectomy, such as upper division and lingulectomy, should yield identical oncological clearance to left upper lobectomy. We compared the prognosis of segmentectomy with that of lobectomy for early stage non-small-cell lung cancer (NSCLC) in the left upper lobe.

METHODS

We retrospectively examined 2115 patients who underwent segmentectomy or lobectomy for c-stage I (TNM 8th edition) NSCLC in the left upper lobe in 2010. We compared the oncological outcomes of segmentectomy (n = 483) and lobectomy (n = 483) using a propensity score matching analysis.

RESULTS

The 5-year recurrence-free and overall survival rates in the segmentectomy and lobectomy groups were comparable, irrespective of c-stage IA or IB. Subset analyses according to radiological tumor findings showed that segmentectomy yielded oncological outcomes comparable to those of lobectomy for non-pure solid tumors. In cases where the solid tumor exceeded 20 mm, segmentectomy showed a recurrence-free survival inferior to that of lobectomy (p = 0.028), despite an equivalent overall survival (p = 0.38).

CONCLUSION

Segmentectomy may be an acceptable alternative to lobectomy with regard to the overall survival of patients with c-stage I NSCLC in the left upper lobe.

Outcomes of Completion Lobectomy for Locoregional Recurrence after Sublobar Resection in Patients with Non-small Cell Lung Cancer

Background

This retrospective study aimed to determine the treatment patterns and the surgical and oncologic outcomes after completion lobectomy (CL) in patients with locoregionally recurrent stage I non-small cell lung cancer (NSCLC) who previously underwent sublobar resection.

Methods

Data from 36 patients who initially underwent sublobar resection for clinical, pathological stage IA NSCLC and experienced locoregional recurrence between 2008 and 2016 were analyzed.

Results

Thirty-six (3.6%) of 1,003 patients who underwent sublobar resection for NSCLC experienced locoregional recurrence. The patients' median age was 66.5 (range, 44-77) years at the initial operation, and 28 (77.8%) patients were men. Six (16.7%) patients underwent segmentectomy and 30 (83.3%) underwent wedge resection as the initial operation. The median follow-up from the initial operation was 56 (range, 9-150) months. Ten (27.8%) patients underwent CL, 22 (61.1%) underwent non-surgical treatments (chemotherapy, radiation, concurrent chemoradiation therapy), and 4 (11.1%) did not receive treatment or were lost to follow-up after recurrence. Patients who underwent CL experienced no significant complications or deaths. The median follow-up time after CL was 64.5 (range, 19-93) months. The 5-year overall survival (OS) and post-recurrence survival (PRS) were higher in the surgical group than in the non-surgical (p<0.001) and no-treatment groups (p<0.001).

Conclusion

CL is a technically demanding but safe procedure for locoregionally recurrent stage I NSCLC after sublobar resection. Patients who underwent CL had better OS and PRS than patients who underwent non-surgical treatments or no treatments; however, a larger cohort study and long-term surveillance are necessary.

Is lobectomy superior to sub-lobectomy in non-small cell lung cancer with pleural invasion? A population-based competing risk analysis

Background

Pleural invasion (PL) has been regarded as an unfavorable prognostic factor for non-small cell lung cancer (NSCLC). But there was no agreement on the optimal surgical extent in NSCLC patients with PL. We aimed to compare the survival outcomes of lobectomy and sub-lobectomy in these patients.

Method

2717 patients were included in the Surveillance, Epidemiology, and End Results (SEER) database and divided into the lobectomy and sub-lobectomy groups. The propensity score matching (PSM) and competing risk analysis were implemented. Then the predictive nomogram was constructed and validated.

Results

2230 Patients received lobectomy while the other 487 patients underwent sub-lobectomy. After 1:1 PSM, the cumulative incidence of cancer-specific death (CSD) was lower in the lobectomy group compared with the sub-lobectomy group (1-year: 12% vs. 15%; 3-year: 30% vs. 37%, 5-year: 34% vs. 45%, P = 0.04). According to the subgroup analysis, the patients who underwent lobectomy suffered lower CSD in the N0–1 stage, adenocarcinoma, and PL-2 cohort (p < 0.05). And there was a significant relationship between the sub-lobectomy group and CSD in the multivariate competing risks regression analysis (HR, 1.26; 95%CI, 1.02–1.56; P = 0.034). Furthermore, a competing event nomogram was constructed to assess the 1-, 3-, and 5-year chances of CSD based on the variables from the multivariate analysis. The 1-, 3-, 5-year area under the receiver operating characteristic curve (AUC) values were 0.720, 0.706, and 0.708 in the training cohort, and 0.738, 0.696, 0.680 in the validation cohorts, respectively. And calibration curves demonstrated ideal consistency between the predicted and observed probabilities of CSD.

Conclusion

Lobectomy should be considered the preferred surgery compared to sub-lobectomy for NSCLC patients with PL. The proposed nomograms presented great prediction ability for these patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09634-w.

Lung Metastases: Current Surgical Indications and New Perspectives

Pulmonary metastasectomy is an established treatment that can provide improved long- term survival for patients with metastatic tumor(s) in the lung. In this mini-review, we discuss the state of the art of thoracic surgery in surgical management of lung metastases which actually occurs for a large part of surgical activity in thoracic surgery department. We describe the principles of surgical therapy that have been defined across the time, and that should remain the milestones of lung metastases treatment: a radical surgery and an adequate lymphadenectomy. We then focus on current surgical indications and report the oncological results according to the surgical approach (open vs. mini-invasive), the histological type and number of lung metastases, and in case of re-metastasectomy. Finally, we conclude with a brief overview about the future perspectives in thoracic surgery in treatment of lung metastases.

Identifying Lung Cancer Patients Suitable for Segmentectomy: A Brief Review

Background: In 1995, a clinical randomized controlled study (RCT) conducted by the Lung Cancer Study Group (LCSG) pointed out that the lobectomy was the gold standard for treating early lung cancer. However, with the development of technology, the results of several retrospective studies have shown that the efficacy of pulmonary segmentectomy is equivalent to that of lobectomy. Currently, it is still controversial whether segmental resection or lobectomy should be performed for early lung cancer. Thus, we aim to summarize the indications of segmentectomy.

Methods: To conduct the review, previous researches involving indications of segmentectomy were collected from the literature using Pubmed. These articles were published and accepted in English in the medical literature from 2013 to 2020. We have focused on segmentectomy and its indications.

Results: A total of 176 articles were retrieved from the Pubmed database, of which 31 articles included indications for segmentectomy. We summarized the relevant content, and the potential and prospect of segmentectomy for the treatment of lung cancer were emphasized.

Conclusions: These findings have a number of important implications for future practice. Pulmonary segmentectomy is a very vital surgical procedure for select patients with lung cancer, which provides a novel approach for the treatment of lung cancer and the survival of lung cancer patients.

The role of the surgeon in treating patients with lung cancer. An updating article

Lung cancer is a type of neoplasia with one of the highest incidences worldwide and is the largest cause of mortality due to cancer in the world today. It is classified according to its histological and biological characteristics, which will determine its treatment and prognosis. Non-small cell lung cancer accounts for 85% of the cases, and these are the cases that surgeons mostly deal with. Small cell lung cancer accounts for the remaining 15%. Surgery is the main method for treating early stage lung cancer, and lobectomy is the preferred procedure for treating primary lung cancer, while sublobar resection is an alternative for patients with poor reserve or with very small tumors. Surgeons need to be trained to use the resources and techniques available for lung resection, including less invasive approaches such as video-assisted thoracoscopic surgery (VATS) and robotic-assisted thoracoscopic surgery (RATS), and need to be familiar with new oncological approaches, including curative, adjuvant or palliative treatments for patients with lung cancer.

Combination of nitrous oxide and the modified inflation-deflation method for identifying the intersegmental plane in segmentectomy: A randomized controlled trial

Background

During thoracoscopic segmentectomy, accurately and rapidly identifying the intersegmental plane (ISP) is of great importance. This study aimed to investigate the effect and safety of a nitrous oxide (N₂O)/oxygen (O₂) inspired mixture on the appearance time of the ISP (T_ISP) via the modified inflation‐deflation method.

Methods

A total of 65 participants who underwent segmentectomy were randomized into three groups: 75% N₂O (n = 24), 50% N₂O (n = 23) or 0% N₂O (n = 18). The 75% N₂O group received a gas mixture of N₂O/O₂ (Fio₂ = 0.25), the 50% N₂O group received N₂O/O₂ (Fio₂ = 0.5), and the 0% N₂O group received 100% oxygen during lung expansion. The appearance time of satisfactory and ideal planes was recorded. Furthermore, arterial blood gas at breathing room air, one‐lung ventilation (OLV) before lung expansion, 5 and 15 min after lung expansion were also recorded.

Results

T_ISP was significantly shorter in the 75% N₂O group (320.2 ± 65.9 s) compared with that of the 50% N₂O group (552.4 ± 88.9 s, p < 0.001) and the 0% N₂O group (968.3 ± 85.5 s, p < 0.001), while the 50% N₂O group was shorter than that of the 0% N₂O group (p < 0.001). Arterial oxygenation was significantly improved in the 0% N₂O group only after lung expansion, before which there were no differences in mean PaO₂ values among groups.

Conclusions

The use of N₂O in the inspired gas mixture during lung expansion is an applicable strategy to rapidly identify the ISP via the modified inflation‐deflation method without any adverse effect on OLV related arterial oxygenation during segmentectomy.

Prospective study of recurrence at the surgical margin after wedge resection of pulmonary metastases

BACKGROUND

Pulmonary metastasectomy is a common treatment for selected patients with pulmonary metastases. Among pulmonary resections, wedge resection is considered sufficient for pulmonary metastases. However, a major problem with wedge resection is the risk of local recurrence, especially at the surgical margin. The aim of this prospective study was to explore the frequency of and the risk factors for recurrence at the surgical margin in patients who underwent wedge resection for pulmonary metastases.

METHODS

Between September 2013 and March 2018, 177 patients (220 lesions) with pulmonary metastases from 15 institutions were enrolled. We studied 130 cases (169 lesions) to determine the frequency of and risk factors associated with recurrence at the surgical margin in patients who underwent wedge resection. Moreover, we evaluated the recurrence-free rate and disease-free survival after wedge resection.

RESULTS

A total of 81 (62.3%) patients developed recurrence. Recurrence at the surgical margin was observed in 11 of 130 (8.5%) cases. The 5-year recurrence-free rate was 89.1%. Per patient, multivariable analysis revealed that the presence of multiple pulmonary metastases was a significant risk factor for recurrence. Per tumor, distance from the surgical margin and tumor/margin ratio were risk factors for local recurrence. The 5-year disease-free survival rate was 34.7%, and the presence of multiple pulmonary metastases and small surgical margin were risk factors for disease-free survival by univariable analysis.

CONCLUSIONS

Among patients who undergo wedge resection for pulmonary metastasis, patients with multiple pulmonary metastases tend to develop recurrence at the surgical margin.

Sublobectomy versus lobectomy for long-term survival outcomes of early-stage non-small cell lung cancer with a tumor size ≤2 cm accompanied by visceral pleural invasion: a SEER population-based study

Background

The optimal surgical strategy for early-stage non-small cell lung cancer (NSCLC) with visceral pleural invasion (VPI) remains unclear. Due to limited prospective comparative data for these surgical modalities, the objective of the current study was to compare the long-term survival outcomes of sublobectomy (Sub) versus lobectomy (Lob) for NSCLC with a tumor size ≤2 cm and VPI.

Methods

Patients with early-stage NSCLC characterized by VPI diagnosed between 2004 and 2013 were identified from the Surveillance, Epidemiology, and End Results (SEER) program. The baseline demographic and cancer characteristics, treatment information as well as survival outcome data were extracted from the SEER database, and confounders were balanced by propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) analyses. Lung disease-specific survival (DSS) and overall survival (OS) rates were compared with Cox proportional hazards (PH) regression models based on the unmatched cohort, the propensity-based matched cohort, and the IPTW cohort.

Results

Of the 1,386 patients enrolled, 1,000 (72.15%) and 386 (27.85%) underwent lobectomy and sublobectomy, respectively. The 5-year DSS rate was 78.64% for the lobectomy group and 59.47% for the sublobectomy group. Cox regression models demonstrated that the operation type (Sub vs. Lob) was an independent prognostic factor for early-stage NSCLC with VPI based on the three different cohorts. Patients who underwent lobectomy showed better long-term DSS and OS rates than those treated with sublobectomy after PSM [DSS: hazard ratio (HR) 0.689, 95% confidence interval (CI): 0.490–0.968, P=0.032; OS: HR 0.723, 95% CI: 0.549–0.953, P=0.021]. The IPTW analysis yielded similar results.

Conclusions

Lobectomy showed superior long-term survival compared with sublobectomy in patients with early-stage NSCLC with a tumor size ≤2 cm and VPI.

Optimal sublobar resection for c-stage I non-small cell lung cancer: significance of margin distance to tumor size ratio and margin cytology (Supplementary analysis of KLSG-0801): complete republication

BACKGROUND

Sublobar resection for lung cancer is associated with a higher risk of recurrence than that of lobectomy; we evaluated the factors considered to be predictors of recurrence.

METHODS

By analyzing multicenter prospective studies of sublobar resection for patients with c-stage I non-small lung cancer who were unable to undergo lobectomy (KLSG-0801), we investigated the relationship between (1) tumor location (TL) and margin distance from the stump (MD), (2) the MD/tumor size (TS) ratio and prognosis, (3) and the margin cytology (MC) and prognosis.

RESULTS

The correlation between TS and MD was statistically significant in cases of easily resectable regions defined by Lewis' classification (n = 18). However, there was no correlation in difficult-to-resect regions (n = 14). Among cases of recurrence, the MD/TS ratio was less than 1. The 3-year survival rate was 100% for patients with MD/TS > 1 (n = 12), 59.7% for patients with MD/TS ≤ 1 (n = 20) (p = 0.06), 88.1% in cases of negative MC (n = 18), and 20% in cases of positive MC (n = 5) (p = 0.001).

CONCLUSION

Cases with positive MC had a significantly worse prognosis than those with negative MC. It may be difficult to secure an MD greater than the TS in a difficult-to-resect region according to Lewis' classification.

Prognostic impact of underlying lung disease in pulmonary wedge resection for lung cancer

BACKGROUND

Pulmonary wedge resection is an option for lung cancer patients with limited cardiopulmonary preservation. As the impact of underlying lung status on the prognosis of such patients remains unclear, we assessed this issue.

METHODS

A total of 149 borderline surgical candidates with localized lung cancer who had undergone wedge resection were retrospectively investigated. Clinical variables related to perioperative morbidity, local control rate, and oncological outcomes based on underlying lung disease were analyzed.

RESULTS

According to the risk analysis of postoperative complications, underlying lung disease did not influence the surgical morbidity. Postoperative recurrence occurred in 65 patients (locoregional recurrence in 36, distant metastasis in 12, and both simultaneously in 17). Multivariate analysis revealed that emphysema on computed tomography (CT) [hazard ratio (HR) 0.45; 95% confidence interval (CI) 0.21-0.99] was an independent indicator of locoregional recurrence. Forty-four patients died of lung cancer and 29 of other causes. Multivariate analysis demonstrated that interstitial lung disease on CT (HR 1.98; 95% CI 1.01-3.89) was a predictor of poor prognosis.

CONCLUSION

Pulmonary wedge resection can be safely undergone by lung cancer patients regardless of pulmonary comorbidity, although underlying lung disease may influence the prognosis after wedge resection.

Prognostic impact of preoperative comorbidities in geriatric patients with early-stage lung cancer: Significance of sublobar resection as a compromise procedure

OBJECTIVES

In high-risk operable geriatric patients undergoing palliative sublobar resection (SR), noncancerous comorbidities may contribute to unfavorable outcomes. The purpose of this retrospective study was to evaluate the perioperative safety and long-term survival of palliative SR in this patient population.

MATERIALS AND METHODS

We reviewed 232 patients (141 male, 91 female) aged ≥75 years who underwent surgical resection of clinical stage I lung cancer from 2006 to 2014. The patients were divided into two groups, lobectomy and SR, and preoperative comprehensive comorbidities were assessed using the Adult Comorbidity Evaluation 27 (ACE-27) and compared between the two groups. The operative safety was compared using the Clavien-Dindo classification. Survival rates were calculated with a Kaplan-Meier model under propensity score matching, and prognostic factors were analyzed using a Cox proportional hazard model.

RESULTS

Lobectomy was performed in 156 patients and SR in 76 (segmentectomy, n = 50; wedge resection, n = 26). Age (p = 0.0137), tumor size on computed tomography (p < 0.0001), central tumor location (p = 0.0008), and high ACE-27 scores (p = 0.0202) were significantly associated with selection of SR. No mortality occurred, and the incidence of Grade 3b or greater postoperative complications in lobectomy and SR was 5.1% and 5.3%, respectively. According to the analysis of propensity score-matched patients (n = 57, tumor size = 23 mm, and consolidation/tumor ratio = 83%), the 5-year survival rate in lobectomy and SR was 81.1% and 73.5%, respectively (p = 0.4374). The ACE-27 score was a more significant prognostic factor than the type of surgical procedure, as well as consolidation/tumor ratio and nodal metastatic status.

CONCLUSIONS

The severity of preoperative comorbidities is a significant prognostic factor, and SR as a compromise surgical procedure may provide promising short- and long-term outcomes in selected geriatric patients with clinical stage I lung cancer.

Clinical Features of Ground Glass Opacity-Dominant Lung Cancer Exceeding 3.0 cm in the Whole Tumor Size

BACKGROUND

Ground glass opacity (GGO)-dominant lung adenocarcinoma sized 3.0 cm or less in the whole tumor size is widely known to have an excellent prognosis and is regarded as early lung cancer. However, the characteristics and prognosis of lung cancer showing GGO exceeding 3.0 cm remains unclear.

METHODS

From 2002 through 2012, we reviewed 3,735 lung cancers that underwent complete resection at our institution. We identified 160 lung cancers (4.3%) showing GGO exceeding 3.0 cm on thin-section computed tomography and divided them into three types by the consolidation/tumor ratio (CTR) using cutoff values of 0.25 and 0.5. We compared the characteristics and prognosis among these types.

RESULTS

Type A (CTR, 0 to ≤0.25), type B (CTR, >0.25 to ≤0.5), and type C (CTR, >0.5 to <1.0) were found in 16 (10%), 37 (23%), and 107 lesions (67%), respectively. No lymph node metastasis was found in types A and B. Recurrence was not observed in types A and B. The 5-year overall survival and disease-free survival rates were both 100% in type A, both 97.2% in type B, and 88.4% and 66.7% in type C, respectively. Patients with type C had a significantly worse prognosis than those with the other types with respect to overall survival and disease-free survival.

CONCLUSIONS

A patient with GGO-dominant lung cancer exceeding 3.0 cm can be considered to be in a group of patients with nodal-negative disease and an excellent prognosis.

Video-assisted thoracoscopic subsegmentectomy for small-sized pulmonary nodules

Segmentectomy has been widely performed as one of the types of limited resections that are performed for the resection of small-sized lung nodules. Video-assisted thoracoscopic surgery has also been in demand as a minimally invasive surgery. Subsegmentectomy is a much more limited resection than segmentectomy, but the technique is complex because it requires keen anatomical identification of small pulmonary structures. Therefore, there has been little reported about subsegmentectomy in medical literature. The recent development of computed tomography is remarkable, and some reports describe three-dimensional computed tomography as providing useful information because it assists surgeons in the performance of thoracoscopic anatomical subsegmentectomy. The creation of an intersubsegmental line is a key process in subsegmentectomy, therefore, some methods have been reported. We have safely and accurately performed some video-assisted thoracoscopic subsegmentectomies for small-sized lung tumors, using the three-dimensional computed tomography simulation and creating the intersubsegmental line with the inflation-deflation technique. In this article, we describe the recent techniques and roles of video-assisted thoracoscopic subsegmentectomy, and offer prospects for this procedure with our clinical data.

The Impact of Margins on Outcomes After Wedge Resection for Stage I Non-Small Cell Lung Cancer

BACKGROUND

The relationship between margin distance and recurrence and survival for stage I non-small cell lung carcinoma (NSCLC) less than or equal to 2 cm is not clear.

METHODS

Patient clinicopathologic data were reviewed from a pooled data set of stage I NSCLC lesions less than or equal to 2 cm resected by wedge resection at Brigham and Women's Hospital (BWH) between 2000 and 2005 and the International Early Lung and Cardiac Action Program (I-ELCAP) between 1999 and 2015. Multivariable models were constructed to evaluate the relationship between margin distance and recurrence and survival, adjusting for patient age, sex, tumor size, and histologic type. Optimal margin distance was determined for recurrence-free and overall survival using maximum χ² values among survival distributions.

RESULTS

Of 182 cases, 138 tumors had margin distance reported (113 BWH and 25 I-ELCAP). The average tumor size was 13.3 mm, and margin distance was 8.3 mm. During a mean follow-up of 49.6 months, there were 33 recurrences and 59 deaths. Increased margin distance was independently associated with lower risk of recurrence (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.83-0.98). Margin distance was also independently associated with longer survival (hazard ratio [HR], 0.94; 95% CI, 0.90-0.98). A margin distance greater than 9 mm was associated with longest recurrence-free survival and a margin distance greater than 11 mm was associated with longest overall survival.

CONCLUSIONS

Increased margin distance was independently associated with lower risk of recurrence and longer overall survival in patients undergoing wedge resection for NSCLC tumors less than or equal to 2 cm. These findings suggest that with a minimum appropriate margin distance, wedge resection may yield outcomes comparable to those of lobectomy.

Concomitant Interstitial Lung Disease Is a Risk Factor for Pleural Invasion in Lung Cancer

BACKGROUND

Lung carcinoma is often associated with interstitial lung disease (ILD), and the prognosis of lung cancer accompanied by ILD is unfavorable. In this study, cases of patients with primary lung cancer with or without ILD were reviewed to analyze surgical outcome, with special interest in the conformity of clinical and pathologic stages, pathologic findings of pleural invasion, malignant pleurisy first detected at the time of thoracotomy, and survival.

METHODS

Retrospective chart review was performed for 1,264 primary lung cancer patients who underwent surgery from 2004 to 2015. Concomitant ILD was diagnosed by pathological examination or preoperative chest computed tomography findings.

RESULTS

ILD was found in 104 patients (8.2%) with primary lung cancer. Conformity of clinical and pathological stages in the ILD-positive patients was poor, with a lower kappa value than that for the 1,160 ILD-negative patients (0.34 versus 0.51). The ILD group had significantly higher incidences of pleural invasion and unexpected malignant pleurisy than did the non-ILD group (for pleural invasion, 49.0% versus 24.5%, p < 0.0001; for malignant pleurisy, 7.69% versus 1.47%, p < 0.0001). The 5-year overall survival rates of the ILD group showed significantly lower than those of the non-ILD group (45.2% versus 70.1%; p = 0.0014) after propensity score matching.

CONCLUSIONS

In lung cancer, the concomitant existence of ILD is a risk factor for pleural invasion. Concomitant ILD might cause underestimation of clinical staging, increase the chance of unexpected malignant pleurisy during surgery, and shorten survival time.

Therapeutic strategy for small-sized lung cancer

Minimizing the volume of lung resection without diminishing curability has recently become an important issue in primary lung cancer. In this review, we will discuss the current state of the feasibility of sublobar resection and specific issues for a segmentectomy procedure. A previous randomized controlled trial showed that lobectomy must still be considered the standard surgical procedure compared with sublobar resection for T1N0 non-small cell lung cancer with a tumor less than 3 cm in size. Since then, supporting studies for segmentectomy of lung cancer with a tumor less than 2 cm in size were reported. In addition, segmentectomy seems to be feasible for clinical stage I adenocarcinoma less than 2 cm in size, in women younger than 70 years old, with a low tumor 18F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) standardized uptake value (SUV) from propensity-matching studies. In a meta-analysis of sublobar resection vs. lobectomy, intentionally performed sublobar resection showed equivalent outcomes to lobectomy. In the near future, two ongoing prospective, randomized trials will report results. As specific issues for the surgical procedure of segmentectomy, achieving a sufficient surgical margin is an important issue for preventing loco-regional recurrence. More studies regarding the regional lymph node dissection area for segmentectomy are needed. Sublobar resection has the potential to become the standard procedure for peripheral small-sized lung cancer less than 2 cm. However, more information is needed about the characteristics of this cancer and the surgical procedure, including nodal dissection.

Hafnium-doped hydroxyapatite nanoparticles with ionizing radiation for lung cancer treatment

Recently, photodynamic therapy (PDT) is one of the new clinical options by generating cytotoxic reactive oxygen species (ROS) to kill cancer cells. However, the optical approach of PDT is limited by tissue penetration depth of visible light. In this study, we propose that a ROS-enhanced nanoparticle, hafnium-doped hydroxyapatite (Hf:HAp), which is a material to yield large quantities of ROS inside the cells when the nanoparticles are bombarded with high penetrating power of ionizing radiation. Hf:HAp nanoparticles are generated by wet chemical precipitation with total doping concentration of 15mol% Hf(4+) relative to Ca(2+) in HAp host material. The results show that the HAp particles could be successfully doped with Hf ions, resulted in the formation of nano-sized rod-like shape and with pH-dependent solubility. The impact of ionizing radiation on Hf:HAp nanoparticles is assessed by using in-vitro and in-vivo model using A549 cell line. The 2',7'-dichlorofluorescein diacetate (DCFH-DA) results reveal that after being exposed to gamma rays, Hf:HAp could significantly lead to the formation of ROS in cells. Both cell viability (WST-1) and cytotoxicity (LDH) assay show the consistent results that A549 lung cancer cell lines are damaged with changes in the cells' ROS level. The in-vivo studies further demonstrate that the tumor growth is inhibited owing to the cells apoptosis when Hf:HAp nanoparticles are bombarded with ionizing radiation. This finding offer a new therapeutic method of interacting with ionizing radiation and demonstrate the potential of Hf:HAp nanoparticles in tumor treatment, such as being used in a palliative treatment after lung surgical procedure.

STATEMENT OF SIGNIFICANCE

Photodynamic therapy (PDT) is one of the new clinical options by generating cytotoxic reactive oxygen species (ROS) to kill cancer cells. Unfortunately, the approach of PDT is usually limited to the treatment of systemic disease and deeper tumor, due to the limited tissue penetration depth of visible light (620-690nm). Here we report a ROS-enhanced nanoparticle, hafnium-doped hydroxyapatite (Hf:HAp), which can trigger ROS when particles are irradiated with high penetrating power of ionizing radiation. The present study provides quantitative data relating ROS generation and the therapeutic effect of Hf:HAp nanoparticles in lung cancer cells. As such, this material has opened an innovative window for deeper tumor and systemic disease treatment.

Radiologic findings to predict low-grade malignant tumour among clinical T1bN0 lung adenocarcinomas: lessons from histological subtypes

OBJECTIVE

Some clinical T1bN0 (cT1bN0) lung adenocarcinomas (2-3 cm) are thought to have less-aggressive and less-malignant behaviour although most cT1aN0 tumours (≤2 cm) are indolent. The present study aimed to identify pre-operative radiographic findings that can predict cT1bN0 lung adenocarcinoma with low-malignant aggressiveness in consideration of histological subtypes.

METHODS

The clinicopathological features and prognoses of 224 consecutive patients (histological subtype set, n = 122; prognosis set, n = 224) with cT1bN0 lung adenocarcinoma were retrospectively examined. Adenocarcinoma in situ, minimally invasive adenocarcinoma, lepidic, node-negative papillary and node-negative acinar predominant invasive adenocarcinomas were defined as low-grade malignant, whereas solid, micropapillary, node-positive acinar and node-positive papillary predominant invasive adenocarcinoma were defined as high-grade malignant.

RESULTS

Receiver operating characteristics analysis revealed that the criteria of solid tumour size ≤1.8 cm on high-resolution computed tomography and the maximum standardized uptake value ≤3.2 on positron emission tomography/computed tomography could predict low-grade malignant tumour in the histological subtype set. Among 95 (42.4%) of 224 patients who met the criteria for the prognosis set, 94 (98.9%) had no lymph node metastasis and 93 (97.9%) had no recurrence (median follow-up, 43.6 months). The 3 year recurrence-free survival rates were 94.9 and 79.0% in patients whose pre-operative findings met and did not meet the criteria, respectively.

CONCLUSIONS

Pre-operative radiographic findings of solid tumour size and the maximum standardized uptake value could identify low-grade malignant tumour among cT1bN0 lung adenocarcinomas, which account for about half of all cT1bN0 tumours. Patients with pre-operative lung tumour findings that fulfill the criteria could be candidates for sublobar resection.

Feasibility of segmental resection in non-small-cell lung cancer with ground-glass opacity

OBJECTIVES

Recently, lung segmental resection has been increasingly performed in patients with lung cancer. In this study, the results of radical segmentectomy (RS) and palliative segmentectomy (PS) were compared retrospectively.

METHODS

Segmentectomy was performed to remove a primary lung cancer in 87 cases. RS was performed for pure ground-glass opacity (GGO), >50% GGO and diameter less than 2 cm and less than 10 mm solid tumours. PS was performed in patients with poor lung function or relapse, or at high risk for surgery. A total of 84 cases, excluding 3 cases of relapse, were investigated.

RESULTS

The pathological stage of RS was IA in 32 (94.1%) and IB in 2 (5.9%). The pathological stage of PS was IA in 23 (46.0%), IB in 15 (30.0%), IIA in 5 (10.0%), IIB in 1 (2.0%), IIIA in 4 (8.0%) and IV in 2 (4.0%). The preoperative characteristics of RS were compared with those of PS for pathological stage I. The mean age was significantly lower for RS cases (67.4 ± 9.9 years) than for PS cases (73.0 ± 9.0 years; P = 0.013). Tumour size was significantly smaller in RS cases (14.7 ± 4.6 mm) than in PS cases (22.0 ± 8.9 mm; P < 0.001). The tumour standardized uptake value of 18F-fluorodeoxyglucose positron emission tomography was significantly lower in RS cases (1.2 ± 1.6) than in PS cases (6.0 ± 6.1; P < 0.001). Serum carcinoembryonic antigen level was lower in RS cases (2.8 ± 1.8 ng/ml) than in PS cases (4.9 ± 5.0; P = 0.019). The mean duration of drainage was shorter in RS (2.5 ± 0.7 days) than in PS (3.9 ± 2.6 days; P = 0.004). Postoperative complications occurred in 6 RS cases (17.6%) and 12 PS cases (29.3%). Overall 5-year survival was higher in RS (100%) than in PS (66.2%; P = 0.003). Five-year disease-free survival was higher in RS (100%) than in PS (66.2%; P = 0.002). Recurrence was detected in 6 PS patients; 10 PS cases showed tumour with GGO and survived without recurrence.

CONCLUSIONS

Our RS is feasible for stage I lung cancer with specific computed tomography features, such as small size, GGO or peripheral location.