RESUMO
LESSONS LEARNED: Pregabalin is a medication that can decrease neuronal hyperexcitability, relieve neuropathic pain, and reach stable plasma levels after a titration period of only a few days.Its use during oxaliplatin infusions was not able to decrease the incidence of chronic, oxalipaltin-related neuropathic pain, compared with placebo. BACKGROUND: Patients with colorectal cancer (CRC) receiving oxaliplatin (OXA) develop acute and chronic painful oxaliplatin-induced peripheral neuropathy (OXAIPN). Acute and chronic OXA-related neuropathies have different pathophysiological bases, but both lead to a common phenomenon: central sensitization (CS) of nociceptive neuronal networks, leading to increased sensitivity (hyperlgesia, allodynia) in the somatosensory system, the common ground of chronic neuropathic pain. Because CS is related to increased risk of painful OXAIPN, we hypothesized that preemptive use of the anti-hyperalgesic drug pregabaline (known to decrease CS) during OXA infusions would decrease the incidence of chronic OXAIPN. METHODS: Pain-free, chemotherapy-naïve CRC patients receiving at least one cycle of modified-FLOX [5-FU(500 mg/m2)+leucovorin(20 mg/m2)/week for] 6 weeks+oxaliplatin(85 mg/m2) at weeks 1-3-5 every 8 weeks] were randomized (1:1) into the study. Patients received either pregabalin or placebo for 3 days before and 3 days after each OXA infusion and were followed for up to 6 months. Clinical assessments were performed at baseline, at the end of chemotherapy, and after the follow-up period. The main outcome was average pain at the last visit assessed by the visual analogic scale (0-10) item of the Brief Pain Inventory (BPI). Secondary endpoints were presence of neuropathic pain according to the Douleur Neuropathique-4 (DN-4), pain dimensions (short- form McGill Pain Questionnaire [MPQ]), Neuropathic Pain Symptom Inventory (NPSI), and changes in nerve conduction studies (NCS) and side effect profile. RESULTS: One hundred ninety-nine patients (57.0 ± 10.7 years old, 98 female, 101 male) were randomized. Data from 56 patients were not included in the analyses (as they did not receive at least one full cycle of modified FLOX). Data from 78 patients in the pregabalin group and 65 patients in the placebo group were retained for analyses. At the last visit, pain intensity in the pregabalin group was 1.03 (95% confidence interval [CI] = 0.79-1.26), and 0.85 (95% CI = 0.64-1.06) in the placebo group, which did not reach significance. Scores from the BPI, MPQ, DN-4, NPSI, and NCS and side-effect profiles and incidence of death did not differ between groups. Quality of life (QoL) score did not differ between groups (placebo = 76.9 ± 23.1, pregabalin group 79.4 ± 20.6). Mood scores were not significantly different between groups (placebo 9.7 [8.1-11.2]; pregabalin 6.8 [5.6-8.0]). CONCLUSION: The preemptive use of pregabalin during OXA infusions was safe, but did not decrease the incidence of chronic pain related to OXAIPN.