RESUMO
BACKGROUND: Previous studies have shown the efficacy of tapentadol (TP) for chronic cancer pain. We evaluated multiple effectiveness aspects of TP prolonged release on moderate-severe cancer-related pain, neuropathic pain (NeP), patient satisfaction, and quality of life. METHODS: An observational prospective study was conducted on 80 cancer patients. Opioid-naïve patients received a starting dose of prolonged-release TP 50 mg twice daily, and opioid-experienced patients were switched to TP, not to exceed 500 mg/day. Treatment response was evaluated at 3, 6, 30-40, and 60-70 days through response rate, numeric rating-scale scoring, survival analysis (time to event for response), pain-intensity difference, TP escalation-index percentage, and effects on NeP. The drug-sparing effect on concomitant therapies was evaluated. RESULTS: Seventy of 80 patients (88%) were responders to treatment (95% CI 78%-94%). Compared to T0, pain-intensity reductions were statistically significant for all intervals (P<0.01), with better results at T3/T4. NeP was significantly reduced at T4 (P<0.01). The probability of response was low at the initial stages and increased during the study. Pain-intensity differences decreased during the study, though without significance. Two patients (2.5%) left the study for TP-induced side effects. A significant improvement in quality of life was observed after 30-40 days (P<0.01). The majority of patients were "satisfied", "very satisfied", or "extremely satisfied" (T3-T4). CONCLUSION: TP was effective in terms of drug-sparing effect, response rate, TP escalation-index percentage, and NeP management. By comparing data from the survival analysis with the response rate and time to response (numeric rating scale from T0 to T4), we found that although TP induced a quick response, a longer period of therapy and higher doses were needed to improve the positive result.
RESUMO
Prostate cancer is one of the most difficult cancers to treat especially when it becomes hormone resistant such as castrate resistant prostate cancer (CRPC) and subsequent metastatic CRPC. Apart from the genetic alterations in prostate cancer, epigenetic modifications also play an important role in the development and neoplastic progression of this disease. These include DNA methylation, histone modifications, and non-coding microRNAs. miRNAs are a novel class of small endogenous single-stranded non-coding RNAs of 19-25 nucleotides in length that typically silence gene expression. Considering the reversibility of epigenetic alterations in early carcinogenesis process, reversion (correction) of these modifications by green tea catechins could be a promising strategy for cancer chemoprevention and therapy. Recent evidence suggests that green tea catechins such as epigallocatechin gallate (EGCG) not only act as epigenetic modulators but can also modify miRNA expression and their target mRNAs, consistently contributing to the inhibition of prostate carcinogenesis. Various studies also indicate that several green tea polyphenols (GTPs) exert synergistic effects with other cancer chemotherapeutic agents. Therefore, the use of appropriate combinations of green tea catechins with the existing chemotherapeutics will lead to a reduction in side effects without decreasing the chemotherapeutic effects. This review will summarize the key results from recent studies detailing the effects of green tea catechins such as EGCG on epigenetic alterations and miRNA expression in prostate cancer.