Dr. Jia Ruan Reviews Updates in T-Cell Lymphoma Research and Treatment

SOSS_Jia_RuanT-cell lymphoma is a complex form of non-Hodgkin lymphoma caused by abnormal clonal growth of mature T-cell lymphocytes. The disease is uncommon, affecting approximately 5-10 percent of lymphoma patients in the United States.

Historically, T-cell lymphoma was classified according to histological (microscopic anatomy) features, but thanks to new technology such as next-generation DNA sequencing and gene expression profiling, we are now able to refine disease classification based on molecular features and cell of origin. Dr. Jia Ruan discussed some of these updates at the OncLive State of the Science Summit on Hematologic Malignancies.

The most common subtypes of systemic peripheral T-cell lymphoma (PTCL) are: peripheral T-cell lymphoma not otherwise specified (PTCL-NOS), anaplastic large-cell lymphoma (ALCL), and angioimmunoblastic T-cell lymphoma (AITL). Cutaneous T-cell lymphoma (CTCL) primarily affects the skin and tends to be less aggressive compared to systemic subtypes.

While outcomes vary by T-cell lymphoma subtype, the five-year overall survival rate for systemic PTCL (with the exception of ALK+ ALCL) is between 20-30 percent, which Dr. Ruan said is suboptimal and indicative of a need for progress from a clinical research and clinical management standpoint.

Physician-researchers are taking steps to improve efficacy of initial T-cell lymphoma therapy so that as many patients as possible can achieve complete remission (CR) and stay in remission for as long as possible. Strides include incorporating frontline stem cell transplant as a way to prolong progression-free survival (PFS) in a portion of patients, as well as moving novel agents into initial combination therapy.

To date, four FDA-approved novel agents, namely pralatrexate (anti-folate), romidepsin (histone deacetylase or HDAC inhibitor), brentuximab vedotin (CD30 antibody-drug conjugate), and belinostat (HDAC inhibitor), are being evaluated in clinical trials for evidence of enhanced effectiveness when combined with cyclophosphamide, doxorubicin hydrochloride, vincristine, prednisone (CHOP)-like chemotherapy. Clinicians eagerly await the results of these studies.

In CTCL, Weill Cornell Medicine (WCM) and NewYork-Presbyterian’s (NYP) multidisciplinary approach to healthcare allows medical oncologists and dermatologists to collaboratively diagnose and manage cases, as well as offer a range of treatment options. For cases with thin layers of skin involvement, skin-directed therapies include steroids, topical chemicals, light therapy, and electron beam radiation. For cases that progress from the skin to the lymphatic and blood system, treatment may include systemic agents like romidepsin, retinoid analogues like bexarotene, and vorinostat, an oral HDAC inhibitor. Combinations of topical therapy and systemic treatment, as well as novel options through clinical trials, are also considered whenever appropriate.

At the Lymphoma Program at WCM/NYP, the overarching goal in the context of T-cell lymphoma is to use cutting-edge next-generation sequencing of patient samples in order to better understand T-cell lymphoma biology, and to then apply a personalized approach to pair patients with the appropriate clinical trials and optimal conventional therapies.

Watch Dr. Ruan speak with OncLive about classification of T-cell lymphomas in this video:

Health Disparities and the Global Landscape of Lymphoma Care Today

The American Society of Clinical Oncology (ASCO) Annual Meeting brings together more than 30,000 oncology professionals each year to encourage discourse on leading research, state-of-the-art treatments, and ongoing controversies in the field. At this year’s Annual Meeting in Chicago, our own Dr. Adrienne Phillips was selected to present a review of the current health disparities in lymphoma care.

Adrienne Phillips

According to the National Institute on Minority Health and Health Disparities, health disparities are defined as “differences in incidence, prevalence, morbidity, mortality and burden of diseases and other adverse health conditions that exist among specific population groups.”

Dr. Phillips explained that health disparities may be due to a variety of factors, including race, gender, biology, and social and environmental differences such as socioeconomic status, health literacy, trust in the healthcare system, proximity to a healthcare facility, and access to and type of health insurance. For example, being uninsured or receiving government-assisted insurance increases patients’ risk of death by 1.5 times. Even patients’ place of residence may play a role, with treatment in rural, community-based settings being associated with inferior overall survival (OS) rates compared to treatment in urban, academic-based settings.

What Dr. Phillips and other physicians find most disconcerting about disparity in lymphoma care is that the disease is often amenable to effective therapy, but a significant segment of the population does not, or cannot, access appropriate care. For example, survival rates for some lymphomas skew lower for black people than for white people. Dr. Phillips conjectured that while African Americans tend to have poorer outcomes, the disparity is likely due to issues related to healthcare access and socioeconomic status.

According to an analysis of 701 people with diffuse large B-cell lymphoma (DLBCL) treated at two southern referral centers with a large black patient population (University of Alabama at Birmingham and Emory University in Atlanta), race did not influence outcomes. Black and white patients who received standard DLBCL chemotherapy drug combination rituximab, cyclophosphamide, doxorubicin hydrochloride, vincristine sulfate, and prednisone (R-CHOP) achieved similar OS rates (5y OS, 79% vs 70%).

Biological factors may also play a role in health disparities, and scientists are constantly working to better understand molecular factors in tumor development regardless of patient ethnicity.

In general, lymphoma is less common among African Americans and Asian Americans, but specific subtypes – like T-cell lymphoma in African Americans and natural killer T-cell (NKT) lymphoma in Asian Americans – are more common in these populations. Thus, Dr. Phillips highlighted a need for ethnic and racial diversity in clinical trial recruitment and in future studies of socioeconomic status and disease biology in order to better understand and improve outcomes for all patients.

Is Cutaneous T-Cell Lymphoma Hereditary?

Patients often question whether various lymphoma types run in families, concerned that their own diagnosis may indicate cancer risk for their loved ones, as well. When an inquiry regarding the possibility of genetic predisposition in cutaneous T-cell lymphoma (CTCL) recently came through our clinic, we sat down with expert Jia Ruan, MD, PhD, to break down what we know and what we don’t know about the cause of this rare and complex condition.Dr. Ruan at computer

T-cell lymphomas are a form of non-Hodgkin lymphoma caused by abnormal growth of mature T-cell lymphocytes, a type of white blood cell found in the immune system. In healthy people, T-cell lymphocytes are responsible for attacking foreign antigens and viruses, and aiding B-cell lymphocytes in antibody production – but by the process of clonal evolution, the T-cell lymphocytes mutate and produce abnormal offspring that become lymphoma. When T-cell lymphomas affect the skin, they are known as cutaneous T-cell lymphomas (CTCL).

The most common subtype of CTCL, mycosis fungoides (MF), occurs when malignant cells develop from CD4+CD45RO+ T-lymphocytes and migrate to the skin. Symptoms include scaly and itchy rash-like patches that may thicken over time and develop into a plaque or a tumor. If the cancer then makes its way from the skin to the lymphatic and blood system, MF becomes the more aggressive Sézary syndrome (SS). MF patients with limited skin symptoms do very well with skin-directed treatment, such as light therapy and topical medicines including steroids, while those with more extensive skin involvement or SS often require systemic treatment.

Although mycosis fungoides and Sézary syndrome are the most common types of cutaneous T-cell lymphoma, they are still quite rare, occurring in only 4-5 percent of non-Hodgkin lymphoma cases, with about 3,000 new diagnoses per year. The median age at diagnosis is 50-70, with a prevalence in men and African Americans.

It is in part due to their rarity that doctors and researchers have yet to understand what causes MF/SS. While there is no definitive evidence of familial risk of CTCL, scientists are continually evaluating whether genetics play a role in the disease formation.

Human leukocyte antigen (HLA) genes, which enable the immune system to discern between proteins native and foreign to the body, possess specific variations, or alleles, that are inherited via the family germline and passed through generations. When a certain HLA class II allele (specifically DQB1*04) was measured in a study of six families, each with occurrences of mycosis fungoides in two first-degree relatives, researchers found the allele to appear more frequently in patients than in the healthy control population, thus suggesting an association of the allele with familial MF. It is worth noting, however, that although some familial clusters of MF have been reported, the vast majority of CTCL cases occur without a familial link.

Additionally, deep genetic sequencing (whole exome) of mycosis fungoides samples, in which the patients’ DNA was analyzed to identify genetic variants, revealed recurrent mutations that seem to be acquired during a lifetime, rather than inherited – also known as somatic mutations. Somatic mutations are believed to be a leading factor in the unchecked cell division in most cancers. The examples of alterations included genes involved in: T-cell activation and programmed cell death (apoptosis), NF-κB signaling that plays a role in cell proliferation and survival, remodeling of chromatin (the DNA and proteins from which chromosomes are derived), and DNA damage response.

Without any strong scientific evidence of hereditary susceptibility, CTCL will likely continue to be thought of as an acquired disorder. Those with skin rash who are concerned about risk and family history are encouraged to see a dermatologist, who can refer to an oncologist or other specialist if the CTCL diagnosis is confirmed.

References:

Journal of the American Academy of Dermatology, 2005 Mar; 52: 393–402.

Nature Genetics, 2015 Sep; 47(9): 1011-9.