Clinical Features, Treatment and Prognosis of Extranodal NK/T Cell Lymphoma, Nasal Type: A Retrospective Analysis of 88 Cases From a Single Institution in China

Extranodal NK/T Cell Lymphoma, nasal type (NKTCL), a rare malignancy in western countries, behaves distinct clinicopathologic features. Patients are generally refractory to conventional chemotherapy. No standard therapy regimen has been established yet. Prognosis of this highly aggressive disease is usually dismal. As it is relatively prevalent in the southwest China, the analysis will provide useful information on the clinical characteristics, treatment options and survival.

Hospitalized patients newly diagnosed as NKTCL according to the WHO classification in our institution from January 2000 to December 2010 were surveyed. 88 cases were retrospectively analyzed. Patients were treated by different regimens: chemotherapy-alone, radiotherapy-alone or radio-chemotherapy. All patients had thorough baseline and follow-up assessments. The median observation time was 28 months (range 3∼96).

1. Patients characteristics: median age 37 years old (range 12∼83), the M:F ratio is 2.7:1, including Ann Arbor stage I 33 cases (40.2%), stage II 12 cases (14.6%), stage III 10 cases (12.2%), stage IV 27cases (32.9%). Systemic symptoms were seen in 49 patients(59.8%). 55 patients(62.5%) present with nasal cavity or nasopharynx involvement. Lymphadenopathy, bone marrow infiltration and splenomegaly were observed in 34.2%, 12.2% and 17.1% of cases, respectively. 3 patients (3.7%) had haemophagocytic syndrome at diagnosis. 94.4% of patients showed a CD56⁺ phenotype. EBER-ISH was positive in 94.9% of patients with nasal presentation, comparing to 68.8% of those with lymphoma occurring outside the nasal cavity. All cases had CD45RO or CD3εexpression. Ki-67 was detected in 39 cases, which the median value was 53% (range 5∼90%), and 53.8% of the patients had a Ki-67 index more than 50%.

2. 65 patients were evaluable for response. The overall response rate was 88.9% for patients received radiotherapy alone (9 cases, 77.8% of them were stage I or II), 65.5% for those received chemotherapy alone (29 cases, 34.5% of them were stage I or II) and 85.2% for the radio-chemotherapy group (27cases, 74.1% of them were stage I or II). It indicated that chemotherapy alone produced a lower response rate compared to radiotherapy alone or combined radio-chemotherapy (P<0.05). There were no statistically significant differences in response among the various chemotherapy regimens, including CHOP-like, LVP, SMILE, GLIDE, ICE, etc.

3. The median OS was 24 months in the whole group. OS at 1 year, 2 years and 5 years was 69.4%, 38.9% and 20.8%, respectively, and PFS was 59.7%, 37.5%, and 19.4%, respectively. Advanced stage, onset of extra-nasal involvement and bone marrow infiltration had been associated with poorer outcome (P<0.05). Respectively, OS at 1 year and 5 years was 43.3% and 6.7% in the radiotherapy-alone group, 77.8% and 22.2% in the chemotherapy-alone group, and 67.9% and 39.3% in the radio-chemotherapy group. No apparent differences were observed among chemotherapy regimens.

NKTCL occurs most often in young or middle aged adults with a male predominance and has a strong association with Epstein-Barr virus (EBV) infection. Patients with advanced stage disease usually have a poor prognosis. Better response and higher survival chances are expected by radiotherapy or combined radio-chemotherapy.

No relevant conflicts of interest to declare.