CHOP Is Insufficient for Newly-Diagnosed Subcutaneous Panniculitis-like T-Cell Lymphoma Patients: A Retrospective Study of 32 Patients in China

Introduction:

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is an exceedingly rare and distinctive subtype of cutaneous lymphoma primarily affecting subcutaneous adipose tissue. SPTCL accounted for only 0.6% of cutaneous lymphomas in the US. However, the incidence in Asia is higher, representing from 2% to 11% of cutaneous T-cell lymphoma. The standard of care for SPTCL has not been well-defined.

Methods:

This retrospective study analyzed the efficacy of the CHOP-regimen in newly-diagnosed SPTCL patients in China. A series of 32 patients with newly diagnosed SPTCL at Peking Union Medical College Hospital between September 1997 and September 2017, were included in this study. Survival were estimated using the method of Kaplan-Meier and used for univariate analysis, and statistical comparison was done by log-rank testing. All reported p-values are two-sided, and values of p<0.05 were considered significant. Relationships between subgroups were examined by Pearson test or the Fisher exact test, where appropriate. Statistical analyses were performed with SPSS 20.0 software.

Results:

This SPTCL cohort had a median age of 27 years. Notably, 14 (43.8%) patients were males and 10 (31.3%) patients were ≤20 years old. All patients presented with nodular skin lesions or subcutaneous deep lesions, primarily affecting the lower extremities (65.6%) and the trunk (56.3%). Eighteen patients (56.3%) were classified as TNM stage III/IV, sixteen patients (50.0%) had a PIT score of 2 or higher, seventeen patients (53.1%) had an IPI score of 3 or higher, and nine patients (28.1%) had concurrent hemophagocytic lymphohistiocytosis. Histopathology typically showed a lobular panniculitis with individual adipocytes surrounded by atypical lymphocytes, usually with a CD3⁺, CD4^-, CD8⁺, CD56^- phenotype.

At a median follow-up duration of 95.1 months, 28 patients received conventional chemotherapies as initial treatment for SPTCL, and 82.1% (23/28) of them were treated with CHOP or CHOP-like regimen. Four patients didn't receive any chemotherapy. The objective response rate (ORR) of the 28 patients receiving chemotherapy was 42.9%. The complete remission (CR) rate and partial remission (PR) rate were 35.7% and 7.1%, respectively. Five patients died of disease progression or therapy-related side effects. The median progression-free survival (PFS) and overall survival (OS) of the entire group of patients was 3.2 months and 147.5 months. The 2-year and 5-year PFS were 38.9% and 29.2%, and the 2-year and 5-year OS were 79.7% and 74.7%. In responding group (N=12, CR and PR), the median PFS and OS were not been reached. In non-responding group (N=16, SD and PD), the median PFS and OS were 1.7 months and 147.5 months. The responding group exhibited a significantly longer PFS, but there was no discernible difference in OS between two groups. Concurrent HLH (p=0.010) and PIT≥2 (p=0.023) were found to be significantly more frequent in non-responding group. Among 16 primary refractory patients and 2 relapsed patients, 14 patients received salvage chemotherapy including polychemotherapies followed by hematopoietic stem cell transplantation, immunosuppressive drugs such as cyscloporine, and novel drugs such as bortezomib and lenalidomide.

Univariate cox regression analysis found that HLH (p=0.010) and PIT≥2 (p=0.037) were significantly affect PFS in univariate analysis. The median PFS were 1.7 and 32.1 months in patients with and without HLH, respectively (p=0.003). The median PFS were 1.8 and 42.1 months in patients with and without PIT≥2, respectively (p=0.031). No significant predictor of PFS was found in multivariate Cox regression and no significant predictor was found in univariate and multivariate analysis of OS.

Conclusions:

As the largest retrospective study in Asian countries, we addressed clinical profiles, phenotypic features, outcome and prognostic factors in SPTCL. Although most SPTCLs received CHOP-like therapy, the efficiency was unsatisfied, and novel drugs should be considered as an alternative option. In the future, more studies are needed to establish appropriate treatment strategies for SPTCL, to validate the predictive factors, and to identify the patients who will benefit from polychemotherapy or chemo-free therapy.

No relevant conflicts of interest to declare.