What is papillary adenocarcinoma?
Papillary adenocarcinoma is a type of cancer that is characterised by cells organised in finger-like projections (referred to as papillae), which are covered by cancerous cells. The word 'adenocarcinoma' refers to cancer that originates in a gland. Therefore, papillary adenocarcionma can occur in multiple sites of the body, including the prostate, kidneys, breasts, and very rarely in the lung. In general, papillary adenocarcinoma is rare and highly heterogeneous type of cancer with various symptoms (which are sometimes nonspecific) with a relatively good prognosis. However, papillary adenocarcinoma can be a dangerous cancer, especially at later stages. It is therefore important to consult any symptoms early with a doctor.
What are the signs and symptoms?
As papillary adenocarcinoma can occur in multiple sites and is rather a type of tumour as opposed to a specific cancer, the signs and symptoms can vary based on the position of the tumour.
In the case of papillary renal cell carcinoma (in the kidney), common symptoms include blood in the urine, pain in the side, unexplained weight loss, excessive fatigue, a lump or mass in the side, and unexplained fever [2].
In the prostate, papillary adenocarcioma may present with symptoms such as pain while urinating (dysuria) and a sensation of residual urine after urinating [3]. If the tumour is in the thyroid gland, symptoms may include a painless lump or swelling in the neck, enlarged lymph nodes, hoarse voice or difficulty speaking, difficulty swallowing, and neck pain [4].
With gastrointestinal cancers, symptoms can include weight loss, sudden onset of diabetes mellitus, loss of appetite, tiredness, and abdominal discomfort or pain. As the disease progresses, jaundice (yellowing of the eye whites and/or skin) and fever may present [5]. In the breast, papillary adenocarcinoma presents with a palpable, centrally located mass or bloody nipple discharge (also referred to as Paget's disease of the nipple) [6]. In the rare case of pulmonary papillary adenocarcinoma, most patients are asymptomatic, and the tumour is usually discovered during a routine chest X-ray or as an incidental finding with other diseases [7].
As papillary often presents with non-specific symptoms, additional investigations are required for a definitive diagnosis. Experiencing these symptoms does not automatically indicate cancer. However, these symptoms should be consulted with a medical professional.
How is papillary adenocarcinoma diagnosed?
The diagnosis of papillary adenocarcinoma is largely dependent on the location of the tumour. In the breast, the tumours are diagnosed by mammography, a type of X-ray of the breast. A core needle biopsy (small sample of the tumour obtained under local anaesthesia) is usually taken in the case of a suspicious finding, which is then examined histopathologically (the tissue is sliced into thin slices and stained with various dyes that react with certain molecules so that they are highlighted under the microscope). A pathologist then confirms the type of the tumour, which may be papillary adenocarcinoma, based on the presence of the finger-like cells [8].
For papillary adenocarcinoma of the prostate, the presence of the papillary regions near the verumontanum - a structure on the bottom of the urethra is a key indicator. Immunohistochemical staining for prostatic specific antigen is also used in the diagnosis [9].
In the case of papillary thyroid cancer, physical examination for lumps or nodules is performed, alongside blood tests to assess thyroid hormone levels. This is followed by a fine-needle aspiration biopsy, followed by microscopic assessment of the cells [4].
Additionally, imaging tests may also be used to assess the size and location of the tumour, as well as involvement of lymph nodes and presence of metastases elsewhere in the body. These may include ultrasound, CT scan, MRI, and PET scan [4].
What is the prognosis and treatment?
The prognosis of papillary adenocarcinoma largely depends on the size, stage and location of the tumour. Compared to the other adenocarcinomas, the prognosis of papillary adenocarcinoma is better. Most papillary adenocarcinomas in the thyroid gland do not cause death. Current therapy is effective in 80% - 90% of patients, however, some subtypes may have a poorer prognosis [10]. The prognosis of the gastrointestinal papillary adenocarcinomas depends on the location and subtype - broadly, they can be classified into intestinal and pancreaticobiliary type. The intestinal type has a better prognosis [11].
In the lung, papillary adenocarcinoma is a very rare subtype of invasive pulmonary cancer. Factors such as older age, larger lesions, distant metastases, lymph node invasion, and poor pathological differentiation are associated with a poorer prognosis [12].
The standard treatment for papillary adenocarcinoma also varies depending on the location of the tumour. Generally, surgical resection with wide margins to remove all the cancerous cells is recommended [13, 14]. Gastrointestinal tumours can be resected endoscopically [11]. Additionally, radiotherapy to the site of the tumour or systemic cytotoxic chemotherapy in the case of lymph node involvement. Additionally, there is a large body of research on novel therapies for papillary adenocarcinoma. Targeted therapies for tumours with certain genetic defects, such as BRCA1/2 mutations, mismatch repair (MMR) deficiencies, or NTRK1-3 fusions, have shown considerable efficacy in clinical trials. Drugs like larotrectinib, entrectinib, and pembrolizumab have received FDA approval for the treatment of patients with tumors harbouring these genetic alterations [15].
Papillary adenocarcinoma is a highly heterogeneous disease with complex presentation affecting different organ systems. However, precision medicine approaches and novel therapeutics offer hope to patients worldwide.