At the baseline, the patients with either older age or lower KPS exhibited lower HVLT-R scores. A similar association was observed with the MMSE. Aoyama et al. reported that BM patients aged ≥66 years or those with KPS ≤ 80 had lower baseline MMSE scores than their counterparts . Kurita et al. used the MMSE to analyze the NCF of 1915 cancer patients who underwent treatment with opioids , and they reported that older age and lower KPS were independently associated with MMSE scores <27.