Clinical outcome of patients with anti-Hu-associated encephalomyelitis after treatment of the tumor

To evaluate 1) the effect of the tumor treatment on the clinical course of paraneoplastic encephalomyelitis (PEM) with anti-Hu antibodies, 2) the impact of immunotherapy on the tumor evolution, and 3) the outcome of the small cell lung cancer (SCLC) of PEM patients compared with that of patients without PEM. The authors retrospectively analyzed 51 PEM patients (42 with SCLC, 9 with other tumors) who received antineoplastic treatment with (25 patients) or without (26) concomitant immunotherapy. Tumor response was assessed at the end of the antineoplastic treatment. Progression of PEM was defined as a change of at least 1 point in the Rankin scale measured at the onset and at the end of the tumor treatment. To evaluate the outcome of SCLC, 27 PEM patients with SCLC were matched one-to-one with SCLC patients without PEM for age, performance status, tumor stage, and type of antineoplastic treatment. Thirty-six (70%) patients were neurologically stable at the end of the tumor treatment. In a logistic regression analysis, tumor complete response was the only predictor of PEM stabilization (OR 7.07; 95% CI 1.68 to 29.76; p = 0.006). Immunotherapy did not modify the outcome of the tumor and PEM. Median survival was similar in SCLC patients with and without PEM, but the probability of survival at 30 months was higher in PEM patients with SCLC (OR 5.26; 95% CI 1.0004 to 27.6902; p = 0.03). Complete response of the tumor seems to have a favorable influence on the course of paraneoplastic encephalomyelitis (PEM). Concomitant immunotherapy does not adversely affect the tumor outcome. The small cell lung cancer of PEM patients may have a slightly better evolution than that of patients without PEM.