Prostate cancer begins when cells in the prostate gland grow out of control. This gland, found only in males, is located below the bladder and in front of the rectum. When prostate cancer is diagnosed, a pathologist examines a tissue sample under a microscope. The appearance of these cancer cells and their arrangement into distinct patterns help determine how aggressive the cancer is, guiding medical decisions.
Prostate Cancer Grading System
The Gleason grading system is the primary method used to assess the aggressiveness of prostate cancer. Pathologists assign numerical grades from 1 to 5 to the architectural patterns of cancer cells observed in biopsy samples. A lower grade, such as 1, indicates cells that closely resemble normal prostate tissue, while a higher grade, such as 5, signifies cells that appear highly abnormal and disorganized.
Prostate tumors often contain cells of different grades. To account for this, pathologists identify the two most prevalent patterns within the tumor. The grade of the most common pattern is listed first, followed by the grade of the second most common pattern, and these two numbers are added together to yield the Gleason score. For example, a Gleason score of 3+4=7 indicates that the most common pattern is grade 3 and the second most common is grade 4. Higher Gleason scores, ranging from 6 to 10, suggest a more aggressive cancer that is more likely to grow and spread.
Defining Cribriform Pattern
A cribriform pattern in prostate cancer refers to a specific microscopic appearance of cancer cells. These cells form gland-like structures that contain multiple, distinctive punched-out spaces or holes, giving them a sieve-like or “Swiss cheese” appearance. This architectural arrangement is characterized by a continuous proliferation of tumor cells with intermingled empty spaces.
This particular pattern is classified as a Gleason pattern 4 component. It represents a more complex and disorganized growth compared to Gleason patterns 1, 2, or 3, where glands are well-formed or mildly irregular. Cribriform architecture indicates a higher degree of cellular disorganization and a more aggressive behavior than other pattern 4 variants, such as ill-formed or fused glands.
Significance of Cribriform Pattern 4
Cribriform pattern 4 in prostate cancer is significant as it’s associated with adverse outcomes. This pattern is linked to a higher risk of the cancer extending beyond the prostate capsule (extracapsular extension), invading seminal vesicles, or spreading to lymph nodes. It also correlates with an increased risk of biochemical recurrence following treatment, which is when prostate-specific antigen (PSA) levels rise again after initially falling.
Even when cribriform pattern 4 is a minor component of a Gleason score, such as in a 3+4=7 diagnosis, it often indicates a higher risk of disease progression compared to tumors without this pattern, even with the same Gleason score. Cribriform growth predicts distant metastasis and disease-specific death in patients with Gleason score 7 cancer. It influences risk stratification, placing patients into higher-risk categories requiring more intensive management and follow-up.
Treatment Considerations
Cribriform pattern 4 influences treatment decisions for prostate cancer. Because of its aggressive nature, active surveillance, which involves close monitoring without immediate treatment, is not recommended for cancers with a cribriform component. This applies even to cases that might otherwise be considered lower-risk based on overall Gleason score.
Cribriform pattern 4 often leads to recommendations for definitive treatments. These may include radical prostatectomy, which is the surgical removal of the prostate gland, or various forms of radiation therapy. A combination of modalities may be considered to manage the heightened risk. Multidisciplinary team discussions, involving urologists, radiation oncologists, and pathologists, are crucial for planning a personalized treatment approach that considers the cancer’s specific characteristics, including cribriform pattern 4’s presence and extent.