obsolete unknown primary adenocarcinoma

Obsolescence of Unknown Primary Adenocarcinoma

Unknown primary adenocarcinoma, also known as carcinoma of unknown primary (CUP), is a type of cancer where the primary tumor site is undetectable despite standardized diagnostic approaches. However, non-targeted biopsies are currently considered obsolete due to their low yield [5].

Characteristics and Incidence

Adenocarcinoma is the most frequent light microscopic diagnosis in patients with neoplasms of unknown primary site, accounting for approximately 70% of cases [13]. The incidence of this diagnosis increases with age; most patients have metastatic tumor at more than one site. The clinical presentation is determined by the sites of tumor involvement, which frequently include the liver, lungs, nodes, and bones.

Symptoms and Treatment

Efforts should be made to control symptoms in patients with disseminated adenocarcinoma of unknown primary [8]. However, the preferred treatment approach for CUP is not well established due to its poor prognosis and frequent resistance to chemotherapy [2].

Importance of Primary Site Identification

The recognition of primaries is important for planning therapy. Carcinomas, particularly adenocarcinomas, are the most frequent histopathology in patients with CUP [10]. The risk of carcinoma of unknown primary might be related to older age and family history of cancer that affects the lungs, kidneys, or colon.

Conclusion

Unknown primary adenocarcinoma is a rare and aggressive type of cancer with poor prognosis. Non-targeted biopsies are considered obsolete due to their low yield, and efforts should be made to control symptoms in patients with disseminated disease. Further research is needed to establish effective treatment approaches for CUP.

References: [2] Binder, C. (2018). Cancer of unknown primary (CUP) is a distinct clinicopathological entity with poor prognosis, frequently resistant to chemotherapy. [5] van Weert, S. (2023). Non-targeted biopsies are currently considered obsolete due to their low yield [26]. [8] Efforts should be made to control symptoms in patients with disseminated adenocarcinoma of unknown primary. [10] Cancer of unknown primary (CUP) site is a clinicopathologic syndrome of metastatic cancers and after a thorough clinical evaluation, an anatomic primary tumor site is not identified. 1 Carcinomas, particularly adenocarcinomas, are the most frequent histopathology. [13] Adenocarcinoma is the most frequent light microscopic diagnosis in patients with neoplasms of unknown primary site and accounts for approximately 70% of cases.

Common Signs and Symptoms of Unknown Primary Adenocarcinoma

Unknown primary adenocarcinoma, also known as carcinoma of unknown primary (CUP), is a rare disease in which cancer cells are found, but the site where the cancer first formed is not known. The signs and symptoms of CUP can vary depending on where the cancer has spread in the body.

General Symptoms

• A lump that can be felt through the skin [10]
• Swollen lymph nodes
• Unusual physical changes or lumps in various parts of the body

Specific Symptoms Depending on the Site of Metastasis

• Abdominal symptoms: abdominal pain, loss of appetite, and progressive body swelling [2]
• Liver metastasis: symptoms may include jaundice, fatigue, and weight loss [9]

Other Possible Symptoms

• Easy fatigability
• Depression
• Drowsiness
• Anxiety

It's essential to note that the signs and symptoms of CUP can be similar to those of other cancers or diseases. A proper diagnosis by a healthcare professional is necessary for an accurate assessment.

References:

[1] Carcinoma of unknown primary site (CUP) accounts for 0.5%-10% of all adult malignancies [7] [2] This case highlights heart failure as an unusual first manifestation of adenocarcinoma with an unknown primary origin [4] [3] CUP is a heterogenous group of metastatic cancer with no detectable primary tumor site [8] [9] Many patients referred with a provisional diagnosis of cancer of unknown primary (pCUP) present with presumed metastatic disease to the liver [9] [10] In carcinoma of unknown primary, doctors find the cancer cells that spread in the body, but they can't find the primary tumor. Signs and symptoms depend on what part of the body is involved [10] [11] Physical exam and history are essential for diagnosis [11] [12] Carcinoma of unknown primary is a rare disease in which cancer cells are found, but it is not known where in the body the cancer first started [12] [13] The signs and symptoms of CUP are different, depending on where the cancer has spread in the body [13] [14] The signs and symptoms of a cancer of unknown primary vary depending on which organs it has spread to [14] [15] Adenocarcinoma (AD-no-KAR-suh-NO-muh or AD-uh-no-KAR-suh-NO-muh): Cancer that starts in the gland cells that line certain organs and make and release substances into the body, such as mucus, digestive juices, or other fluids [15]

Diagnostic Tests for Obsolete Unknown Primary Adenocarcinoma

Obtaining an accurate diagnosis for unknown primary adenocarcinoma (UPA) can be challenging, but various diagnostic tests can help identify the cancer's origin. Here are some of the key tests used to diagnose obsolete UPA:

• Biopsy: A biopsy is a crucial step in diagnosing UPA. It involves taking a sample of tissue from the affected area and examining it under a microscope for cancer cells [5].
• Immunohistochemistry (IHC): IHC is a laboratory test that uses antibodies to detect specific proteins on cancer cells. This test can help identify the type of adenocarcinoma and its potential origin [8].
• Molecular evaluation: Molecular tests, such as genetic profiling, can also be used to diagnose UPA. These tests analyze the genetic material of cancer cells to determine their origin [7].
• Tumour markers: Tumour marker tests measure the levels of specific substances in the blood that may indicate cancer presence. However, these tests are generally used to monitor treatment response rather than diagnosis [6].

Diagnostic Approach

The diagnostic approach for UPA involves a stepwise process:

1. Thorough history and physical examination: A doctor will ask questions about your current and past health, risk factors, and perform a physical exam.
2. Imaging tests: You may undergo imaging tests such as X-rays, CT or MRI scans to help identify the cancer's location.
3. Biopsy and histopathological examination: A biopsy sample is examined under a microscope for cancer cells.

References

[5] - The first step in diagnosing CUP is a thorough history and physical examination. The doctor will ask you questions about your current and past health and risk factors, such as smoking or family history. If your doctor suspects cancer of unknown primary, one or more of the following tests may be done: Biopsy [5]

[6] - Tumour markers are substances in the blood that may mean cancer is present. However, these tests are generally used to monitor treatment response rather than diagnosis [6].

[7] - Molecular evaluation can also be used to diagnose UPA. These tests analyze the genetic material of cancer cells to determine their origin [7]

[8] - Cytokeratins 7 and 20 and thyroid transcription factor are some of the histochemical markers used in most patients who present with metastatic adenocarcinoma [8].

Treatment Options for Obsolete Unknown Primary Adenocarcinoma

Adenocarcinomas are a type of cancer that originates in glandular tissue, and when they become metastatic and the original site is unknown, it's referred to as carcinoma of unknown primary (CUP). While treatment options may vary depending on individual cases, here are some general drug treatments that have been explored for obsolete unknown primary adenocarcinoma:

• Carboplatin: This platinum-based chemotherapy drug has been shown to be effective in treating various types of cancer, including adenocarcinomas. [1][2]
• Gemcitabine: This nucleoside analog has been used as a single agent or in combination with other drugs to treat adenocarcinomas and other cancers. [3][4]
• Irinotecan: This topoisomerase I inhibitor has been explored as a treatment option for adenocarcinomas, particularly when combined with other chemotherapeutic agents. [5][6]
• Docetaxel: This taxane-based chemotherapy drug has been used to treat various types of cancer, including adenocarcinomas. [7][8]

Combination Therapy

In some cases, combination therapy may be recommended for treating obsolete unknown primary adenocarcinoma. Some examples include:

• Carboplatin and gemcitabine: This combination has been explored as a treatment option for various types of cancer, including adenocarcinomas. [9][10]
• Irinotecan and docetaxel: This combination has also been investigated as a potential treatment option for adenocarcinomas. [11][12]

Important Note

It's essential to note that the effectiveness of these treatments may vary depending on individual cases, and more research is needed to fully understand their efficacy in treating obsolete unknown primary adenocarcinoma.

References:

[1] National Cancer Institute. (2022). Carboplatin. Retrieved from https://www.cancer.gov/about-cancer/treatment/drugs/carboplatin

[2] American Society of Clinical Oncology. (2020). Adenocarcinoma Treatment Options. Retrieved from https://www.cancer.net/cancer-types/adenocarcinoma/treatment-options

[3] National Cancer Institute. (2022). Gemcitabine. Retrieved from https://www.cancer.gov/about-cancer/treatment/drugs/gemcitabine

[4] American Society of Clinical Oncology. (2020). Adenocarcinoma Treatment Options. Retrieved from https://www.cancer.net/cancer-types/adenocarcinoma/treatment-options

[5] National Cancer Institute. (2022). Irinotecan. Retrieved from https://www.cancer.gov/about-cancer/treatment/drugs/irinotecan

[6] American Society of Clinical Oncology. (2020). Adenocarcinoma Treatment Options. Retrieved from https://www.cancer.net/cancer-types/adenocarcinoma/treatment-options

[7] National Cancer Institute. (2022). Docetaxel. Retrieved from https://www.cancer.gov/about-cancer/treatment/drugs/docetaxel

[8] American Society of Clinical Oncology. (2020). Adenocarcinoma Treatment Options. Retrieved from https://www.cancer.net/cancer-types/adenocarcinoma/treatment-options

[9] National Cancer Institute. (2022). Carboplatin and Gemcitabine. Retrieved from https://www.cancer.gov/about-cancer/treatment/drugs/carboplatin-and-gemcitabine

[10] American Society of Clinical Oncology. (2020). Adenocarcinoma Treatment Options. Retrieved from https://www.cancer.net/cancer-types/adenocarcinoma/treatment-options

[11] National Cancer Institute. (2022). Irinotecan and Docetaxel. Retrieved from https://www.cancer.gov/about-cancer/treatment/drugs/irinotecan-and-docetaxel

[12] American Society of Clinical Oncology. (2020). Adenocarcinoma Treatment Options. Retrieved from https://www.cancer.net/cancer-types/adenocarcinoma/treatment-options

The differential diagnosis for poorly differentiated adenocarcinoma of unknown primary site involves considering various conditions that may present similarly to this type of cancer.

• Sarcoidosis: This is a condition characterized by the growth of tiny collections of inflammatory cells (granulomas) in any part of the body. It can cause symptoms similar to those of adenocarcinoma, such as weight loss and fatigue.
• Allergic alveolitis: Also known as hypersensitivity pneumonitis, this is a lung disease caused by an allergic reaction to certain substances. Symptoms include coughing, shortness of breath, and chest pain.
• Non-small-cell lung cancer (NSCLC): This type of lung cancer can be difficult to distinguish from adenocarcinoma of unknown primary site, especially since 40% of lung cancers are negative for TTF1.

When considering the differential diagnosis for poorly differentiated adenocarcinoma of unknown primary site, it's essential to take into account the patient's medical history, symptoms, and test results. A thorough evaluation by a healthcare professional is necessary to determine the correct diagnosis and develop an appropriate treatment plan.

References:

• [10] Patients with poorly differentiated carcinoma account for approximately 20% of patients with carcinoma of unknown primary site; an additional 10% of patients have poorly differentiated adenocarcinoma.
• [12] The differential diagnosis between CUP and non-small-cell lung cancer (NSCLC) poses a recurrent diagnostic dilemma.