Rare Types of Pancreatic Cancer: Understanding and Treatment

Dr. Ajay Mehta, Director and Head Surgical Oncology, HCG Cancer Centre, Nagpur

Pancreatic cancer is a formidable adversary, notorious for its aggressive nature and high mortality rates. It stands as the fourth leading cause of cancer-related deaths in the United States, striking fear into the hearts of both patients and healthcare professionals. The pancreas, a vital organ responsible for regulating blood sugar levels and aiding in digestion, harbors a potential threat that can manifest in various rare and unique subtypes of cancer. While the majority of pancreatic cancer cases are of the more common adenocarcinoma type, there exist rare subtypes that pose unique challenges for us. Below are the rare types of pancreatic cancer, along with its characteristics, diagnosis, and treatment options.

Causes: 

·         Genetic: Genetic mutations in certain genes lead to the development of pancreatic cancer. For example, mutations in genes such as DAXX, ATRX, MEN1, and other genes are associated with pancreatic neuroendocrine tumours (PNET’s). 

·         Environmental and Lifestyle factors:

a.                   Smoking: Smoking is a well-established risk factor for various types of pancreatic cancer, including rare ones. 

b.                   Obesity: Excess body weight or being overweight is linked with an increased risk of pancreatic cancer specifically rare ones.

c.                   Diet: A diet high in processed and red meat, less consumption of fruits and vegetables, and high in unhealthy amount of fats contribute to the development of pancreatic cancer. 

d.                   Alcohol: Excessive alcohol consumption is another potential risk factor for pancreatic cancer especially rare ones.

e.                   Occupational Hazards: Exposure to certain toxins and chemicals in the workplace is correlated with increased risk of pancreatic cancer. 

·         Other Medical Vulnerabilities: Certain rare types of pancreatic cancer may be associated with specific medical conditions. For instance, intraductal papillary mucinous neoplasms (IPMNs) are often linked to chronic pancreatitis, which can result from various causes, including heavy alcohol use.

·         Hormonal Factors: Pancreatic neuroendocrine tumors (PNETs) are hormone-producing tumors. Hormonal factors and imbalances can play a role in their development.

Symptoms of Rare Pancreatic Cancer:

The symptoms of rare types of pancreatic cancer can vary depending on the type and location of the tumor, and they may overlap with symptoms of more common forms of pancreatic cancer. It’s important to note that many rare types of pancreatic cancer, such as pancreatic                 neuroendocrine tumors (PNETs), may be non-functional, meaning they do not produce noticeable hormonal symptoms.

The most common type of symptoms include nausea, abdominal pain, alarming weight loss without trying, changes in bowel movements, jaundice, vomiting, ulcers and diarrhoea. 

It’s important to remember that these symptoms can also be caused by various other medical conditions, and not everyone with these symptoms will have pancreatic cancer. However, if you experience these symptoms persistent or worsening symptoms, especially if they are at risk for pancreatic cancer due to family history or other risk factors, it’s essential to seek medical attention.

Acinar Cell Carcinoma

Acinar cell carcinoma is a rare subtype of pancreatic cancer that originates in the exocrine glands of the pancreas. Unlike the more common ductal adenocarcinoma, acinar cell carcinoma often presents with different clinical and histological features. It tends to affect a slightly younger patient population and has a better prognosis when diagnosed in the early                 stages.

Diagnosis: Diagnosing acinar cell carcinoma involves a combination of imaging studies, such as CT scans, MRIs, and endoscopic ultrasound, along with a biopsy to confirm the diagnosis.

Treatment: Treatment options for acinar cell carcinoma typically include surgery, chemotherapy, and radiation therapy. Surgical resection offers the best chance of cure, and adjuvant chemotherapy may be recommended to improve outcomes.

Pancreatic Neuroendocrine Tumors (PNETs)

Pancreatic Neuroendocrine Tumors, often referred to as PNETs, are another group of rare pancreatic cancers. These tumors originate from the endocrine cells in the pancreas and can be categorized into functional or non-functional types. Functional PNETs produce hormones         that cause specific symptoms, while non-functional PNETs do not exhibit any hormonal symptoms.

Diagnosis: The diagnosis of PNETs requires a combination of imaging studies, such as CT scans, MRIs, and somatostatin receptor scintigraphy. Blood tests to measure hormone levels may also be conducted.

Treatment: The approach to treating PNETs depends on several factors, including the tumor’s size, grade, and whether it is functional or non-functional. Treatment options may include surgery, chemotherapy, targeted therapy, and somatostatin analogs to manage hormonal symptoms.

Pancreatic Adenosquamous Carcinoma

Pancreatic adenosquamous carcinoma is a rare and aggressive subtype of pancreatic cancer that combines elements of adenocarcinoma and squamous cell carcinoma. It is known for its              rapid growth and tendency to spread to nearby tissues.

Diagnosis: Diagnosing adenosquamous carcinoma often involves imaging studies, such as CT scans and MRIs, and a biopsy to confirm the histological characteristics.

Treatment: The treatment of adenosquamous carcinoma typically involves surgery to remove     the tumor when possible. Chemotherapy and radiation therapy may be used as adjuvant treatments, but the prognosis for this subtype remains challenging.

Solid Pseudopapillary Neoplasm (SPN)

Solid pseudopapillary neoplasm, or SPN, is a rare, low-grade malignant tumor that primarily affects young women. It is characterized by solid and cystic components and generally exhibits a less aggressive clinical course compared to other pancreatic cancer subtypes.

Diagnosis: SPN is often discovered incidentally during imaging studies, such as CT scans or MRIs. Biopsy and histological examination are used to confirm the diagnosis.

Treatment: The primary treatment for SPN is surgical resection, which can provide excellent long-term outcomes. In most cases, patients do not require adjuvant therapy after surgery.

Timely and accurate diagnosis in rare pancreatic cancer is crucial, as it can significantly impact treatment decisions and prognosis. Although these rare subtypes may have varying characteristics and clinical courses, a multidisciplinary approach involving surgical resection, chemotherapy, and radiation therapy remains the cornerstone of treatment. Advances in research and treatment options offer hope for improved outcomes and a brighter future for those affected by these rare pancreatic cancers. Early detection, specialized care, and ongoing research are essential in the battle against these formidable foes.