www.nature.com/scientificreports OPEN Potential risk of disease modifying therapies on neoplasm development and coadjutant factors in multiple sclerosis outpatients Rosalía Gil‑Bernal1, Juan Luis González‑Caballero2, Raúl Espinosa‑Rosso3 & Carmen Gómez‑Gómez1* Neoplasm development in Multiple Sclerosis (MS) patients treated with disease‑modifying therapies (DMTs) has been widely discussed. The aim of this work is to determine neoplasm frequency, relationship with the prescription pattern of DMTs, and infuence of the patients’ baseline characteristics. Data from 250 MS outpatients were collected during the period 1981–2019 from the medical records of the Neurology Service of the HUPM (Hospital Universitario Puerta del Mar)—in Southern Spain—and analysed using Cox models. Neoplasm prevalence was 24%, mainly located on the skin, with cancer prevalence as expected for MS (6.8%). Latency period from MS onset to neoplasm diagnosis was 10.4 ± 6.9 years (median 9.30 [0.9–30.5]). During the observation period β‑IFN (70.4% of patients), glatiramer acetate (30.4%), natalizumab (16.8%), fngolimod (24.8%), dimethyl fumarate (24.0%), alemtuzumab (6.0%), and terifunomide (4.8%) were administered as monotherapy. Change of pattern in step therapy was signifcantly diferent in cancer patients vs unafected individuals (p = 0.011) (29.4% did not receive DMTs [p = 0.000]). Extended Cox model: Smoking (HR = 3.938, CI 95% 1.392–11.140, p = 0.010), being female (HR = 2.006, 1.070–3.760, p = 0.030), and age at MS diagnosis (AGE‑DG) (HR = 1.036, 1.012–1.061, p = 0.004) were risk factors for neoplasm development. Secondary progressive MS (SPMS) phenotype (HR = 0.179, 0.042–0.764, p = 0.020) and treatment‑time with IFN (HR = 0.923, 0.873–0.977, p = 0.006) or DMF (HR = 0.725, 0.507–1.036, p = 0.077) were protective factors. Tobacco and IFN lost their negative/positive infuence as survival time increased. Cox PH model: Tobacco/AGE‑DG interaction was a risk factor for cancer (HR = 1.099, 1.001–1.208, p = 0.049), followed by FLM treatment‑time (HR = 1.219, 0.979–1.517). In conclusion, smoking, female sex, and AGE‑DG were risk factors, and SPMS and IFN treatment‑time were protective factors for neoplasm development; smoking/AGE‑DG interaction was the main cancer risk factor. Although survival afer the onset of Multiple Sclerosis (MS) has historically increased for 17 years, as refected in the frst works 41 years ago, patient life expectancy is, on average, 7 years below the general population data 1. While there are diferent estimations about the increased risk for all-cause mortality (up to threefold), everyone agrees that MS itself is the main cause of death2,3. Disease-modifying therapies (DMTs) have been the most important advance in MS treatment, from the so-called frst-generation drugs, β-interferon (IFN) and glatiramer acetate (GA), approved in the mid-1990s, until the introduction of the latest drugs in the 2010s, such as fngolimod (FLM), alemtuzumab (ALB), dimethyl fumarate (DMF), terifunomide (TRF), or the most recently approved purine analogue, cladribine 4. Despite their benefts, undesirable efects are expected, especially in relation to infection and malignancy 5. IFN liver failure or 1Department of Biochemistry, Faculty of Medicine, University of Cadiz, Plaza Fragela, s/n, 11003 Cadiz, Spain. 2Department of Statistics and Operations Research, Faculty of Medicine, University of Cadiz, Cadiz, Spain. 3Department of Neurology, Hospital Universitario Puerta del Mar (HUPM), Cadiz, Spain. *email: [email protected] Scientifc Reports | (2021) 11:12533 | https://doi.org/10.1038/s41598-021-91912-x 1 Vol.:(0123456789) www.nature.com/scientificreports/ progressive multifocal leukoencephalopathy from natalizumab (NTB), although not frequent, are seen as pos- sible threats in routine clinical practice, unlike the development of neoplasms, a rare but dangerous side efect. In the literature, we found a disparity in the data for both neoplasm frequency in MS patients and the role of DMTs in the neoplasm development, from an increase in cancer-related deaths (1.9-fold)6 to normal or decreased cancer prevalence, although the hazard risk depends on the type of tumour7,8. Increased cancer risk has been observed among patients treated with IFN, GA, NTB, and ALB 9,10. Te development of skin cancer is contem- plated in the technical information about GA, FLM (basal cell and squamous cell skin cancers, Bowen’s disease, melanoma, Kaposi’s sarcoma), and ALB (papilloma) (available at http://www. ema. europa. eu , European Medicines Agency, EMA, last accesed May 2021). Terefore, the aim of this work is to investigate the therapeutic pattern followed and its relationship with the incidence of neoplasia in MS outpatients. We hypothesise that DMTs could constitute risk factors for the development of neoplasia. Patients’ baseline characteristics were considered for their possible contribution to the development of neoplasms. Methods Patient recruitment. Tis retrospective study was based on outpatients from the Department of Neurol- ogy at the Hospital Universitario Puerta del Mar (HUPM), attended to in consultation from onset of MS between 1981 and 2019. According to the Spanish Statistical Ofce, the area served by HUPM had an average popula- tion of 220 thousand during this period (data available at http:// www. ine. es, Instituto Nacional de Estadística, INE). Te data source was the digital medical record used by neurologists conducting a multidisciplinary team. Other independently-trained team members carried out data extraction and statistical analysis. Individuals pre- viously sufering from a neoplasm or diagnosed with Clinically Isolated Syndrome were excluded. As a result, 314 consecutive cases were analysed, 250 of which fulflled the inclusion criteria. Te last case was diagnosed in September 2017, and the follow-up of patients ended on the last database registered individual (March 31, 2019). Measures. Te analysed variables were: (a) demographic and baseline characteristics: sex, age at MS onset (AGE-DG); disease phenotype; as possible contributing factors, neoplasm family history and smoking; (b) fac- tors related to neoplasm development: presence and number of neoplasms; malignancy/benignity; tumour line- age; age at neoplasm onset; latency period from the start of DMTs until neoplasm appearance c) factors related to the medication received: type and number of drugs; use order; treatment time for each drug; length of treatment. Statistical analysis. Categorical variables were expressed as number and percentage of observed data; numeric variables were represented as mean ± standard deviation and median (minimum–maximum). Associa- tion between categorical variables was contrasted by χ2 test, or if these conditions were not verifed, by Fisher’s exact test. Quantitative variable comparisons were performed using the Student’s t-test. Associations were con- sidered signifcant when p < 0.05. For each patient, the observation period (survival time) started with MS diag- nosis until neoplasm appearance or the end of the study (censored case). Several covariate analyses were performed to estimate the role of DMTs and other possible contributing fac- tors to neoplasm development. Te Cox proportional hazard model was used to analyse the predictors associated with the hazard rate (HR), with a 95% confdence interval (CI). For assessing the proportional hazard (PH) for each predictor of interest, we also estimated p-values between the ranked survival and the residuals. When the predictors did not satisfy the PH assumption, an extended Cox model was used. For this purpose, we included time-dependent variables to measure the interaction factor with time exposure 11. Te data were processed using IBM SPSS Statistics 24 and Epidat 3.1 sofware. Ethical considerations. Te study was approved by the Comité de Ética de la Investigación de Cádiz. Ser- vicio Andaluz de Salud. Consejería de Salud. Junta de Andalucía. HUPM. Av. Ana de Viya 21, 11009 CÁDIZ (SPAIN) (phone + 0034 956002100) ([email protected]). Te need of the informed consent was waived by the Comité de Ética de la Investigación de Cádiz. All the experiments were carried out in accord- ance with the relevant guidelines and regulations. Results Patient baseline features. Patient baseline features were registered in Table 1. Women accounted for 63.2% (n = 158) of the individuals. Mean AGE-DG was 34.0 ± 11.3 years (median 32.0 [13–71)], mostly ranging from 20–40 years (62.4%, n = 156). Relapsing–remitting variant (RRMS) (83.2%, n = 208) was the predominant medical condition. Neoplasm family history was present in 10.4% (n = 26) and tobacco consumption in 44% (n = 110) of individuals. In particular, 24% (n = 60) developed some kind of neoplasm, alone or successively. Five patients sufered from a second (n = 4) or a third process (n = 1). Out of the sampled patients, 6.8% (n = 17, 28.3% of neoplastic patients) sufered malignancy and two of these individuals presented benign tumour. Mean age at tumour diagnosis was 46.2 ± 11.3 years (median 45.5 [26–80]) for neoplasm and 52.1 ± 8.4 for malignancy (median 53.0 [37–69]). Feminine gender, smoking, and family history were signifcantly present in neoplasm patients as compared to patients who did not present these characteristics (p < 0.05). Cancer patients were older at AGE-DG (39.8 ± 12.3 years, median 40 [21–64)] than the remaining individuals (33.58 ± 11.12, median 32.0 [13–71], n = 233) (mean (p = 0.027), median (p = 0.043)). Mean MS duration was 13.1 ± 7.8 years. Table 1 shows the observation periods. Te latency period from MS to neoplasm appearance was 10.4 ± 6.9 years (median 9.30 [0.9–30.5]), signifcantly less than the observation period for censured cases (mean 12.8 ± 7.7, median 11.6 [1.3–37.5]) (mean p = 0.031, median p = 0.024).