Prognostic Significance of Ki-67 in Follicular Lymphoma: A Cross-Sectional Study

Abstract Follicular lymphoma (FL) is a B-cell malignancy distinguished by its follicular growth pattern. Ki-67 is a nonhistone protein expressed during the proliferative phase of the cell cycle. In FL, higher Ki-67 correlates with higher histological grade. Studies exploring the prognostic value of Ki-67 in FL have yielded inconsistent and contradictory findings. The objective was to study the association of Ki-67 with survival and known prognostic factors like FL International Prognostic Index (FLIPI). This retrospective study was conducted in the department of medical oncology at a tertiary cancer center in India. It involved patients with FL treated with chemotherapy from January 2014 to December 2015. A total of 152 cases were evaluated The study population consisted of 152 patients, including 98 males and 54 females. According to the Ann Arbor staging, 20 (13.2%) patients were stage I, 27 (17.8%) were stage II, 54 (35.5%) were stage III, and 51 (33.5%) were stage IV. Most of the patients (137) were diagnosed with disease of grade 3a. All of the 152 patients received chemotherapy. After first-line treatment, 136 patients (89.4%) had a complete response, 16 (10.5%) had progressive disease, and 43 (28.3%) patients relapsed. The 5-year progression-free survival (PFS) was 73% and the corresponding overall survival (OS) was 82.2%. By applying the receiver operator characteristic curve analysis, a threshold of 47.5% was identified. Of the total patients, 47 (30.9%) were classified as having high Ki-67 levels, whereas 105 (69.1%) were categorized into the low Ki-67 group. There was no correlation between the Ki-67 index and either treatment response or survival. While patients with low Ki-67 expression showed a trend toward increased PFS (75.2%) than those with high Ki-67 (68.1%), the result was statistically insignificant. No significant associations were found between Ki-67 expression and OS, baseline clinicopathological factors, or the FLIPI score. Our study did not identify any significant correlation between Ki-67 levels and response. While the patients with lower Ki-67 values demonstrated a tendency toward longer PFS, the difference was not statistically significant. OS also remained comparable between the groups.