Comprehensive Genomic Profiling Aids in Distinguishing Metastatic Recurrence from Second Primary Cancers

[Recent Advances in Diagnosis and Treatment Strategies for Multiple Primary Lung Cancer]

As the utilization of computed tomography in lung cancer screening becomes more prevalent in the post-pandemic era, the incidence of multiple primary lung cancer (MPLC) has surged in various countries and regions. Despite the continued application of advanced histologic and sequencing technologies in this research field, the differentiation between MPLC and intrapulmonary metastasis (IM) remains challenging. In recent years, the specific mechanisms of genetic and environmental factors in MPLC have gradually come to light. Lobectomy still predominates in the treatment of MPLC, but the observation that tumor-specific sublobar resection has not detrimentally impacted survival appears to be a viable option. With the evolution of paradigms, the amalgamated treatment, primarily surgical, is an emerging trend. Among these, stereotactic ablative radiotherapy (SABR) and lung ablation techniques have emerged as efficacious treatments for early unresectable tumors and control of residual lesions. Furthermore, targeted therapies for driver-positive mutations and immunotherapy have demonstrated promising outcomes in the postoperative adjuvant phase. In this manuscript, we intend to provide an overview of the management of MPLC based on the latest discoveries.
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Evaluation of surgical outcomes and prognostic factors of second primary lung cancer based on a systematic review and meta-analysis

BACKGROUND

Although surgery has been widely applied for SPLC therapy, there is still no uniform treatment approach. Whether SPLC and primary lung cancer have similar prognostic characteristics remains controversial. Herein, based on a systematic review and meta-analysis, we aimed to enucleate the influences of diverse surgical strategies and underlying prognostic factors on the prognosis of patients with both the first primary lung cancer and SPLC underwent surgical resection.

METHODS

A comprehensive and systematic literature search was implemented in three databases (MEDLINE, EMBASE, and Cochrane), and eligible studies were screened following inclusion and exclusion criteria. Meanwhile, we extracted the hazard ratios (HR) together with 95% confidence intervals (CI) for each prognostic factor, either directly or indirectly, from the enrolled literature.

RESULTS

Eleven studies (published between 2000 and 2022) were included in this study, including 1,131 SPLC patients. The overall survival (OS) exhibited no difference between patients with lobectomy and sublobar resection after SPLC (HR: 0.87, 95%CI: 0.62-1.21, P = 0.41). The patients after completion pneumonectomy had a poor prognosis (HR: 1.85, 95% CI: 1.34-2.55, P < 0.01). Poor prognostic factors after SPLC surgery included synchronous SPLC (HR: 3.38, 95%CI: 1.53-7.46, P < 0.01), tumor diameter > 2 cm (HR: 2.44, 95%CI: 1.73-3.44, P < 0.01), solid predominant in CT morphology (HR: 3.08, 95% CI: 1.14-8.33, P = 0.03), lymph node metastasis (HR: 2.79, 95%CI: 1.40-5.56), and smoking (HR: 2.37, 95%CI: 1.08-26.82, P < 0.01). Tumor disease-free interval (DFI), tumor histological type, and gender had no impact on the prognosis of patients received SPLC surgery.

CONCLUSIONS

Patients with SPLC, especially those with poor cardiopulmonary function reserve, should be prioritized for sublobar resection for treatment. These patients should also try to avoid completion pneumonectomy. Patients with synchronous SPLC, tumor diameter > 2 cm, solid predominant in CT morphology, lymph node metastasis, and smoking had a poor prognosis. Meanwhile, SPLC has similar prognostic characteristics with single primary lung cancer. However, the study has some limitations and more evidence is warranted to verify the findings.

Genomic Profiling With Large-Scale Next-Generation Sequencing Panels Distinguishes Separate Primary Lung Adenocarcinomas From Intrapulmonary Metastases

The distinction between different separate primary lung cancers (SPLCs) and intrapulmonary metastases (IPMs) is a challenging but clinically significant issue. Histopathology-based classification is the current practice; however, it is subjective and affected by interobserver variability. Recently, next-generation sequencing (NGS) panels have been used in lung cancer diagnostics. This study aimed to investigate the value of large-scale NGS panels for distinguishing between SPLCs and IPMs. A total of 32 patients with 69 lung adenocarcinomas were included. Comprehensive histopathologic assessments of multiple pulmonary adenocarcinomas were performed independently by 3 pathologists. The consensus of histopathologic classification was determined by a majority vote. Genomic analysis was performed using an amplicon-based large-scale NGS panel, targeting single-nucleotide variants and short insertions and deletions in 409 genes. Tumor pairs were classified as SPLCs or IPMs according to a predefined molecular classification algorithm. Using NGS and our molecular classification algorithm, 97.6% of the tumor pairs can be unambiguously classified as SPLCs or IPMs. The molecular classification was predictive of postoperative clinical outcomes in terms of overall survival (P = .015) and recurrence-free interval (P = .0012). There was a moderate interobserver agreement regarding histopathologic classification (κ = 0.524 at the tumor pair level). The concordance between histopathologic and molecular classification was 100% in cases where pathologists reached a complete agreement but only 53.3% where they did not. This study showed that large-scale NGS panels are a powerful modality that can help distinguish SPLCs from IPMs in patients with multiple lung adenocarcinomas and objectively provide accurate risk stratification.

A Case Report of Immunotherapy-Resistant MSI-H Gastric Cancer with Significant Intrapatient Tumoral Heterogeneity Characterized by Histologic Dedifferentiation

We describe a patient with both gastric adenocarcinoma and metastatic squamous cell carcinoma (SCC) of unknown primary site. The possibility of a single malignant clonal process as opposed to differing primaries was supported by the finding of both histologies exhibiting high microsatellite instability. Despite evidence of tumor microsatellite instability, the patient’s disease process did not respond to immune checkpoint inhibition. Our pursuit of whole-exome sequencing and comparing the single-nucleotide variant profiles of both tumors supported a single clonal process with the development of significant intratumoral heterogeneity. High intratumoral heterogeneity has posed a challenge to precision medicine approaches, but we also provide a review of the literature of this phenomenon mediating resistance to immunotherapy strategies.

Recent Advances in the Diagnosis and Management of Multiple Primary Lung Cancer

With the wide application of computed tomography in lung cancer screening, the incidence of multiple primary lung cancer (MPLC) has been increasingly reported. Despite the established criteria, the differentiation between MPLC and intrapulmonary metastasis remains challenging. Although histologic features are helpful in some circumstances, a molecular analysis is often needed. The application of next-generation sequencing could aid in distinguishing MPLCs from intrapulmonary metastasis, decreasing ambiguity. For MPLC management, surgery with lobectomy is the main operation method. Limited resection does not appear to negatively affect survival, and it is a reasonable alternative. Stereotactic ablative radiotherapy (SABR) has become a standard of care for patients refusing surgery or for those with medically inoperable early-stage lung cancer. However, the efficacy of SABR in MPLC management could only be found in retrospective series. Other local ablation techniques are an emerging alternative for the control of residual lesions. Furthermore, systemic therapies, such as targeted therapy for oncogene-addicted patients, and immunotherapy have shown promising results in MPLC management after resection. In this paper, the recent advances in the diagnosis and management of MPLC are reviewed.

The Role of Whole Exome Sequencing in Distinguishing Primary and Secondary Lung Cancers

Non-small cell lung cancer (NSCLC) that presents with multiple lung tumors (MLTs) poses a challenge to accurate staging and prognosis. MLTs that arise as clonally related secondary metastases from a common primary are higher stage and often require adjuvant chemotherapy or may in fact be incurable stage IV lesions. Conversely, MLTs that represent distinct primaries have a better prognosis and may be overtreated if inappropriately classified as related secondaries. Historically, pathologic and radiographic criteria were used to distinguish between primary and secondary MLTs; however, the advent of genomic profiling has demonstrated limitations to these historic classification systems. In this review, we discuss the use of molecular profiling to distinguish between primary and secondary lung cancers, with a focus on the insights gleaned from whole exome sequencing (WES) analyses. While WES is not yet feasible in routine clinical practice, WES studies have helped elucidate the clonal relationship between primary and secondary lung cancers and provide important context for the application of targeted sequencing panel-based analyses.

Identification of second primary tumors from lung metastases in patients with esophageal squamous cell carcinoma using whole-exome sequencing

Esophageal squamous cell carcinoma (ESCC) patients with a synchronous or metachronous lung tumor can be diagnosed with lung metastasis (LM) or a second primary tumor (SPT), but the accurate discrimination between LM and SPT remains a clinical dilemma. This study aimed to investigate the feasibility of using the whole-exome sequencing (WES) technique to distinguish SPT from LM.

Methods: We performed WES on 40 tumors from 14 patients, including 12 patients with double squamous cell carcinomas (SCCs) of the esophagus and lung (lymph node metastases were sequenced as internal controls) diagnosed as LM according to pathological information and 2 patients with paired primary ESCC and non-lung metastases examined as external controls.

Results: Shared genomic profiles between esophageal (T) and lung (D) tumors were observed in 7 patients, suggesting their clonal relatedness, thus indicating that the lung tumors of these patients should be LM. However, distinct genomic profiles between T and D tumors were observed in the other 5 patients, suggesting the possibility of SPTs that were likely formed through independent multifocal oncogenesis.

Conclusions: Our data demonstrate the limitations and insufficiency of clinicopathological criteria and that WES could be useful in understanding the clonal relationships of multiple SCCs.

Gallbladder cancer harboring ERBB2 mutation on the primary and metastatic site: A case report

BACKGROUND

Bile duct cancer constitutes gallbladder cancer (GBC), intrahepatic cholangiocarcinoma (ICA), and extrahepatic cholangiocarcinoma (ECA). These three entities show morphological and immunohistochemical resemblance so that it is difficult to differentiate between primary ICA and liver metastasis of GBC, which sometimes becomes a point of discussion in clinical practice. Although these cancers demonstrate significant differences in their mutational landscape, several reports demonstrated shared genomic alteration in paired primary and metastatic site aids in distinguishing metastatic recurrence from second primary cancers.

CASE SUMMARY

We present a 73-year-old female patient who underwent curative resection for GBC harboring epidermal growth factor receptor 2 (ERBB2) activating mutation on next-generation sequencing (NGS)-based genomic testing. One year later, a hepatic lesion was observed on follow-up imaging and she underwent surgical resection for a pathological diagnosis. The histological findings of the hepatic lesion were similar to those of the primary lesion. Additionally, using NGS panel testing, the hepatic lesion was found to have ERBB2 activating mutation, which is the identical mutation detected in the sequencing result of the primary site. ERBB2 activating mutation occurs more frequently in GBC than ICA and ECA. Therefore, in the present case, we think this molecular finding potentiated the diagnosis of the liver mass toward a metastatic recurrence. Additionally, this patient underwent HER2-targeted treatment with lapatinib in combination with capecitabin and obtained clinical benefit.

CONCLUSION

This case illustrated NGS panel usefulness in distinguishing GBC recurrence from second primary cancer and HER2-targeted agent efficacy on ERBB2 mutated GBC.

Identity determination in diagnostic surgical pathology

From a technical perspective, specimen identity determination in surgical pathology over the last several decades has primarily focused on analysis of repetitive DNA sequences, specifically microsatellite repeats. However, a number of techniques have recently been developed that have similar, if not greater, utility in surgical pathology, most notably analysis of single nucleotide polymorphism (SNPs) and gene panels by next generation sequencing (NGS). For cases with an extremely limited sample or a degraded sample, sequence analysis of mitochondrial DNA continues to be the method of choice. From a diagnostic perspective, interest in identity determination in surgical pathology is usually centered on resolving issues of specimen provenance due to specimen labeling/accessioning deficiencies and possible contamination, but is also frequently performed in cases for which the patient's clinical course following definitive therapy is remarkably atypical, in cases of an unexpected diagnosis, and by patient request for "peace of mind". However, the methods used for identity determination have a much broader range of applications in surgical pathology beyond tissue provenance analysis. The methods can be used to provide ancillary information for cases in which the histomorphology is not definitively diagnostic, as for example for tumors that have a virtually identical microscopic appearance but for which the differential diagnosis includes synchronous/metachronous tumors versus a metastasis, and for the diagnosis of hydropic early gestations versus hydatidiform molar pregnancies. The methods also have utility in several other clinical settings, for example to rule out a donor-transmitted malignancy in a transplant recipient, to monitor bone marrow transplant engraftment, and to evaluate natural chimerism.

An Unusual Case Report: Occurrence of Renal Cell Carcinoma, Basal Cell Carcinoma and Chronic Lymphocytic Leukemia in a Case of Papillary Thyroid Carcinoma Treated with Radioactive Iodine

The standard therapy for thyroid cancer is total or near total thyroidectomy, followed by the administration of radioactive iodine for remnant ablation or residual disease. Patients with radioiodine therapy are predisposed to second malignant neoplasms in organs such as central nervous system (CNS), breast, prostate, kidney, bone marrow, salivary gland, and digestive tract. Exposure to carcinogen including occupational and therapy related hazard, aging and genetic susceptibility are other causes of second primary cancers. The second primary malignancies are not uncommon and, nowadays, the prevalence of it is mildly increasing due to the increasing survival of cancer patients and advances in early diagnosis and therapeutic modalities. Here, we present a fifty-one-year-old man with papillary thyroid carcinoma (PTC), who developed chronic lymphocytic leukemia (CLL), renal cell carcinoma (RCC), and basal cell carcinoma (BCC) in 15-20 years after radioactive iodine therapy. Second primary tumors are increasing and environmental, genetic susceptibility and increase in survival of cancer patients are the major risk factors.