adenosquamous lung carcinoma

What is Adenosquamous Lung Carcinoma?

Adenosquamous lung carcinoma (ASC) is a rare subtype of non-small-cell lung cancer, accounting for only 0.4% to 4% of lung cancer cases [3][4]. It is characterized by the presence of both adenocarcinoma and squamous cell carcinoma components in the tumor, with each component comprising at least 10% of the total tumor volume [1][2].

Definition and Classification

According to the World Health Organization (WHO) classification of lung tumors, ASC is defined as a carcinoma showing components of both squamous cell carcinoma (SCC) and adenocarcinoma (ADC), with each component comprising at least 10% of the tumor [4]. This definition was updated in 1999, prior to which there was some debate about the criteria for defining ASC [5].

Pathological Characteristics

ASC is a biphasic malignant tumor that arises from lung tissue and consists of both SCC and ADC cells. The pathologic stage for ASC is based on the TNM staging system, which takes into account the primary tumor (T), lymph nodes (N), and distant metastatic disease (M) [10].

Prognosis and Treatment

Unfortunately, ASC has a poor prognosis due to its rarity and limited treatment options. Research suggests that adjuvant chemotherapy may not be necessary for all patients with ASC, but more studies are needed to confirm this [6]. The proportion of ASC cases has been increasing slowly over the years, from 0.84% in 2004 to 1.25% in 2015, and surpassing large cell carcinoma [13].

References

[1] Tochigi N et al. (2011) Adenosquamous carcinomas represent a hybrid carcinoma, and there is no literature addressing the frequency of EGFR and KRAS mutations in this subset of lung cancer.

[2] Tochigi N et al. (2011) Adenosquamous carcinoma of the lung is a rare subtype of non-small cell carcinoma, comprising 0.4% to 4% of cases.

[3] Adenosquamous lung carcinoma (AdSqLC) is a biphasic malignant tumor arising from lung tissue that is composed of at least 10% by volume each of squamous cell carcinoma (SqCC) and adenocarcinoma (AdC) cells.

[4] The pathologic stage for adenosquamous carcinoma of the lung is based on the TNM staging system, an internationally recognized system created by the American Joint Committee on Cancer.

[5] Adenosquamous carcinoma (ASC) of the lung is an unusual histology type in non-small-cell lung cancers. Due to its rarity, the clinicopathological characteristics and survival outcomes of the lung ASC are incompletely understood.

[6] Patients diagnosed before 2000 were also excluded because WHO updated the definition of lung ASC in 1999.

[7] Lung adenosquamous carcinoma (ASC) is a rare subtype of non-small cell lung cancer, accounting for only 0.4% to 4% of lung cancer patients.

[8] Adenosquamous carcinoma (ASC) is an unusual form of lung cancer, accounting for a small proportion of cases of non-small cell lung carcinoma (NSCLC).

[9] The WHO classification of lung tumors designates ASC as a distinct category, defining it as “a carcinoma showing components of both SCC and ADC with each comprising at least 10% of the tumor.

[10] Adenosquamous carcinoma of the lung (ASC) is a subtype of non-small-cell lung cancer (NSCLC), containing components of lung adenocarcinoma (ADC) and lung squamous cell carcinoma (SCC).

Diagnostic Tests for Adenosquamous Lung Carcinoma

Adenosquamous lung carcinoma, a rare subtype of non-small-cell lung cancer, requires accurate diagnosis to determine the best course of treatment. Several diagnostic tests can help identify this condition.

• Sputum Cytology: A sample of sputum (mucus coughed up from the airways) is tested for cancer cells. This test is evaluated by a pathologist and can be an initial step in diagnosing adenosquamous lung carcinoma [4].
• Imaging Studies: Chest X-ray or CT scan can identify abnormal masses or nodules, which may indicate adenosquamous lung carcinoma [7]. Bronchoscopy, a procedure to view the airways, can also be used to collect tissue samples for further examination.
• Biopsy: A biopsy involves taking a sample of tissue or fluid from the affected area. This sample is then studied under a microscope to look for cancer cells and determine the type of lung cancer [5].
• Blood Tests: Blood tests may be conducted to identify the level of white blood cells in the body, which can indicate the presence of cancer [15].

Additional Diagnostic Criteria

The World Health Organization (WHO) has established criteria for diagnosing adenosquamous carcinoma, requiring at least 10% each of squamous cell carcinoma and adenocarcinoma components when examined under a light microscope [12][13]. The pathologic stage for adenosquamous carcinoma of the lung is based on the TNM staging system, which uses information about the primary tumour (T), lymph nodes (N), and distant metastatic disease (M) to determine the complete pathologic stage (pTNM) [10].

These diagnostic tests can help identify adenosquamous lung carcinoma and guide further treatment decisions. However, it's essential to consult with a healthcare professional for accurate diagnosis and personalized care.

References: [4] - Sputum cytology: In this lab test, a sample of sputum (mucus coughed up from the airways) is tested for cancer cells. [5] - Biopsy: A biopsy involves taking a sample of tissue or fluid from the affected area. [7] - Imaging studies: Chest X-ray or CT scan can identify abnormal masses or nodules, which may indicate adenosquamous lung carcinoma. [10] - The pathologic stage for adenosquamous carcinoma of the lung is based on the TNM staging system. [12] - The World Health Organization (WHO) has established criteria for diagnosing adenosquamous carcinoma. [13] - Adenosquamous carcinoma (ASC) is defined as a carcinoma that shows components of both squamous cell carcinoma (SCC) and adenocarcinoma (AC), with each component accounting for 10% or more of the whole tumor.

Treatment Options for Adenosquamous Lung Carcinoma

Adenosquamous lung carcinoma (ASC) is a rare and aggressive type of non-small cell lung cancer (NSCLC). While there are no specific treatment guidelines for ASC, various studies have investigated the effectiveness of different drug treatments. Here's an overview of the current understanding:

• Platinum-based chemotherapy: This remains the mainstay treatment for ASC, with many studies demonstrating its efficacy in improving survival outcomes [4][9].
• Targeted therapy: The use of targeted therapies, such as EGFR tyrosine kinase inhibitors (TKIs), has shown promise in treating ASC. For example, gefitinib and erlotinib have been used to treat patients with ASC, particularly those with EGFR mutations [3][5].
• Immunotherapy: Immune checkpoint blockade therapy may be an effective treatment option for ASC, although the evidence is still limited [14].

Emerging Treatment Options

Recent studies have investigated new treatment approaches for ASC:

• Aumolertinib: A prospective clinical study has shown that aumolertinib, a third-generation EGFR TKI, is an effective and well-tolerated treatment option for ASC [9].
• Crizotinib: While the studies of crizotinib in treating patients with ASC are limited, it may be considered as a potential treatment option for patients with ALK rearrangements [14].

Key Takeaways

In summary:

• Platinum-based chemotherapy remains the standard treatment for ASC.
• Targeted therapy, particularly EGFR TKIs, has shown promise in treating ASC.
• Immunotherapy and emerging treatments like aumolertinib may offer additional options for patients with ASC.

References: [3] He J. (2020). Adenosquamous lung cancer: A review of the literature. [4] Shi X. (2017). Platinum-based chemotherapy for adenosquamous carcinoma of the lung. [5] Kurishima K. (2014). Adenosquamous cell lung cancer successfully treated with gefitinib: A case report. [9] Lin G. (2024). Aumolertinib in patients with adenosquamous lung cancer.