Multiple Myeloma: Experience in a Tertiary Referral Center in Mexico City

Background

In Western populations the change on incidence rates during time, demographic characteristics and impact of novel therapies in the outcome of patients with multiple myeloma (MM), is well described. Some studies suggest that rates and clinical features are different in some races. In developing countries, novel therapies are not affordable for all health care system. Data of patients on a public health practice in Mexican population have not been described and are scarce in other Latin-American populations.

Methods

Records of a cohort of patients that were diagnosed and prospectively followed at the Multiple Myeloma Clinic at our Institution in Mexico City, from June 2006 to December 2014, were reviewed. Clinical and laboratory data were collected. Continuous variables were described as medians and ranges, categorical variables were described as frequencies and proportions. Survival analysis was performed using the Kaplan-Meier procedure. Survival-related prognostic factors were analyzed with the Cox proportional hazards regression model. Overall Survival (OS) was calculated from time of treatment initiation until death or last visit. Progression-free survival (PFS) was calculated from the time of treatment initiation to the date of progression, failure or death. Patients that did not receive therapy, were not evaluated or had less than 1 month of follow-up were excluded from the survival analysis.

Results

Criteria for diagnosis of MM were fulfilled for 175 patients. There were 98 females and 77 males, median age being 62 years (range, 35-92 years), 15% were ¼50 years old, 60% were ¼64 years old and 19% were ¾74 years. Poor performance status (PS) (ECOG 3 and 4) was found on 28% (n=49). Laboratory data is shown in table 1. Most patients were at an advanced stage of the disease, with 88% in the International Stating System (ISS) categories II and III. Creatinine clearance was below 30 ml/min in 55 patients (31%). Extramedullary disease rate was high, presented in 25% (n=44) of patients. Of the 152 patients that received treatment, the induction regimen in 21% (n=32) was melphalan based, 68% (n=104) thalidomide based and 11% (n=16) Bortezomib based. Only 9 patients (6%) received an autologous transplantation.

The median follow-up was 20 months (range,2-104). A total of 132 patients were included in the survival analysis. The median OS was 45 months (95% CI, 40.9.-49.5) and PFS was 25 months (95% CI, 19.1-31.0).

In the univariate analysis the variable that was associated with a shorter OS was depth of response to induction therapy (p¼0.001). On univariate analysis of PFS, poor PS (p=0.007), stage III ISS (p=0.001), creatinine clearance <30ml/min (p=0.042), presence of ostelytic lesions (p=0.004) and depth of response to induction therapy (p¼0.001) were variables associated with a shorter PFS. On multivariate analysis ISS and depth of response to induction therapy remained significant.

Conclusions

To our knowledge this is the first report of a MM cohort in a tertiary referral public health center in Mexico.

The OS and PFS on this study are significantly lower than the reported on the last decade by studies in Western populations. This fact may be associated to particular clinical and therapeutic features of our population.

These results underscore the high rate of advanced stage disease and poor PS at diagnosis. This may be explained because of a delayed referral of patients, due to decreased availability to medical facilities.

Median OS in MM patients has improved to 7-8 years, due to the incorporation of novel therapies and autologous transplantation. Unfortunately only 10.5% and 8.5% of our patients actually received bortezomib and autologous transplantation, respectively. The lack of access of these resources on our population is reflected in our inferior outcomes.

There is an imperative need of promoting governmental and non-governmental strategies to seek universality on health coverage on developing countries.