Introduction:

Signet ring cells (SRCs) are a rare histopathological feature in prostate cancer, characterized by poorly differentiated cells with a central mucin-containing vacuole. Existing literature, though limited, consistently indicates that SRCs are linked to advanced disease stages and significantly poorer outcomes. This study aims to delve into the clinicopathologic characteristics and long-term outcomes of prostate cancer patients with SRCs on biopsy, offering a more comprehensive understanding of their clinical implications.

Methods:

Under an Institutional Review Board-approved protocol (NCT 02594202), patients with SRCs identified on prostate biopsy between 2007 and 2023 were included. Exclusion criteria encompassed any concurrent extraprostatic malignancies known for SRCs. All patients underwent standard diagnostic workup, including PSA testing and multiparametric MRI (mpMRI). Patients electing to undergo robot assisted laparoscopic prostatectomy (RALP) under went pathological examination such as Gleason grading, tumor location, margin status, and presence of adverse features like extraprostatic extension, seminal vesicle invasion, and lymphovascular invasion. These patients were propensity matched at a 1:2 ratio against non-SRC containing biopsy patients who also underwent RALP and pathologic and long term oncologic outcomes were compared as controls. Statistical analyses used chi-square and Fisher exact tests for categorical variables, t-tests for continuous variables, and Kaplan-Meier curves for estimating biochemical recurrence-free survival and overall survival.

Results:

Sixty-six patients with SRCs were identified. At the time of SRC discovery on prostate biopsy, the median age was 68 years, and the median PSA was 9.86 ng/mL. MRI showed that 57% had PI-RADS 5 index lesions, nearly half (48.8%) had grade group five cancers, and two-thirds of the index lesions were in the peripheral zone. The cohort had a median follow-up of 50 months, with two deaths and one patient having metastasis at presentation. Thirty-one patients underwent RALP and were matched with 62 control patients. Post-operative pathology showed that 61.3% of SRC patients and 51.6% of controls had grade group 4/5 cancers, with three patients in each group upgrading from biopsy. With median follow-up times of 56 months for SRC patients and 45 months for control patients, Kaplan-Meier analysis showed no significant differences in recurrence-free survival, metastasis-free survival, or overall survival between the cohorts (p>.05).

Conclusion:

SRCs in prostate cancer historically indicate aggressive disease, but early detection and treatment improve observed outcomes. Further studies are needed to validate these findings and refine management strategies.

Funding: N/A