Clinicopathologic Factors Associated with Prognosis in Patients with Metastatic Squamous Cell Carcinoma of the Anal Canal: A Multicenter Cohort Study.

OBJECTIVES

Due to its rarity, there is insufficient evidence for managing ASCC patients with distant metastasis. Thus far, the therapeutic strategy for distant metastasis of ASCC is less standardized and requires a more individualized approach. Therefore, it is crucial to obtain information regarding treatment outcomes and prognostic factors following the development of distant metastasis to identify optimal care strategies for better patient outcomes and predict their prognosis.

METHODS

In the multi-institute cohort study conducted in Japan, we retrospectively assessed 58 ASCC patients with synchronous distant metastasis and 28 ASCC patients with metachronous distant metastasis.

RESULTS

When comparing the OS between ASCC patients with synchronous distant metastasis and metachronous distant metastasis, there was no statistically significant difference between the two groups. The OS rate at five years was 37.4% for patients with synchronous distant metastasis and 27.6%; for metachronous distant metastasis. In ASCC patients with synchronous distant metastasis, patients with distant metastasis at multiple sites exhibited extremely worse OS than those at single sites (HR: 4.56, 95% CI: 1.16-18.00, < 0.0001). In addition, in ASCC patients with metachronous distant metastasis, early recurrence was an independent factor for predicting poor OS in the multivariate analysis (HR: 4.13, 95% CI: 1.22-13.94, = 0.022).

CONCLUSIONS

ASCC patients with distant metastasis at multiple sites were a worse prognosis. In addition, early recurrence was identified as an independent prognostic factor for OS among ASCC patients.