The etiology of primary BOT lymphoma is little known, although some cases of lymphomas have been reported in association with the acquired immune deficiency syndrome (Delecluse et al.1997). PTCLs is reported to be distinct from cutaneous T- cell lymphoma and have poor prognosis (Foss et al.2011). According to the fourth edition of the World Health Organization Classification of Tumors of Hematopoietic and Lymphoid Tissues (Swerdlow et al.2008). PTCL, NOS is classified into the nodal lymphoma group in which, along with extranodal and leukemic groups, most of aggressive T-cell lymphoma are included (Campo et al.2011).
Patients with PTCL had a very poor outcome compared with patients with aggressive B-cell lymphoma. The International T-cell Lymphoma Study showed that the overall survival and failure-free survival with PTCL, NOS at 10 to 15 years was 10% (Vose et al.2008). Suzzumiya et al. reported that in aggressive T-cell lymphomas, patients with high IPI score had adverse outcomes compared with patients with low IPI, similar to diffuse large B-cell lymphoma. However, they showed that even patients in the best IPI score group did not have a favorable survival. In this study, the patient showed a bad prognosis even with a low IPI score (Suzumiya et al.2009).
There have been many clinical and laboratory results, which evaluate the molecular and immunohistochemical prognostic factors in PTCL subtypes. Went et al. reported that the proliferation-associated protein Ki-67 was prognostically relevant and a new predictive score including age (>60 years), high LDH, poor performance status, and Ki-67 ≥ 80%. this score was associated with the patient outcome (Went et al.2006). In our study, the patient's Ki-67 was expressed with a high level (about 80%). These results seem to also affect the poor outcomes in this case. In this patient, diagnostic lumbar puncture to rule out central nervous system involvement (CNS) was not performed. In our institution, lumbar puncture is performed if the physician suspects that lymphoma has spread to the central nervous system or bone marrow. In addition, lumbar puncture is performed routinely for aggressive lymphomas (such as primary CNS lymphoma), paranasal sinus, parameningeal, testicular involvement, and patients with lymphobastic lymphoma, Burkitt lymphoma, and blastic variants.
Although there was a poor outcome in our patient, we identified the usefulness of VMAT. During the follow-up period, the patient did not develop any morbidities relating to VMAT, including xerostomia. The patient did not develop grade ≥1 xerostomia according to the RTOG criteria. Xerostomia after RT for Waldeyer's NHL was known to be a considerable morbidity and parotid-sparing RT techniques was recommended to reduce these complications (Chang et al.2009). Traditional RT technique for Waldeyer`s NHL is opposed lateral fields to cover the primary tumor lesion and neck lymph nodes. This RT field also includes the bilateral parotid glands. Therefore, most of patients treated with traditional RT technique experience xerostomia which is permanent toxicity and can alleviate the patient's quality of life. The most well-known parotid sparing technique, intensity modulated radiation therapy (IMRT), improves RT induced xerostomia related quality of life compared to traditional RT technique (Gupta et al.2012; van Rij et al.2008). VMAT is the next version of IMRT and more fast and efficient than IMRT (Verbakel et al.2009).
Although there is no consensus on the question of how to best treat primary BOT lymphoma, the recommended treatment modality for patients with early stage is combined therapy consisting of chemotherapy and RT (You et al.2004). T-cell lymphoma have traditionally been treated much like the B-cell lymphomas, with a combination chemotherapy regimen. Currently, there is no standard first-line regimen for the treatment of PTCL (Foss et al.2011). The most common chemotherapeutic regimen for the treatment of PTCL is the CHOP regimen (Savage2011). According to the trend described above, our patient also received CHOP regimen followed by RT. For patients with recurrent PTCL, the optimal therapeutic management is unclear, and data regarding the outcome for relapsed patients is limited (Lunning et al.2013). The second-line combination regimens are reported to be similar to those studied in relapsed aggressive B-cell lymphomas. These regimens are ICE (ifosphamide, carboplatin, and etoposide), DHAP (dexamethasone, cytarabine, and cisplatin), and ESHAP (etoposide, methylprednisolone, cisplatin, and cytarabine). In this study, eight cycles of salvage chemotherapy with IMEP regimen was followed by RT. Because the recurrence was localized within the orbit at the time of diagnosis of the recurrence, the patient received RT before salvage chemotherapy.
For improving the treatment outcome in primary and relapsed PTCL patients, new therapeutic agents are currently used or in clinical trials. The agents showing activity in PTCL are as follows: immunomodulatory agents (brentuximab, alemtuzumab, and lenalidomide), antifolates (pralatrexate), nucleoside analogs (gemcitabine), histone deacetylase inhibitors (belinostat, vorinostat, and romidepsin) (Petrich and Rosen2013; Karlin and Coiffier2014; Foss et al.2011).
Furthermore, the trials comparing autologous and allogenic hematopoietic cell transplantation in eligible patients were also initiated by the German High-Grade Non-Hodgkin Lymphoma Study Group (Shustov2013). The results of these trials might help elucidate difficult treatment decisions for relapsed PTCL. Some authors believe that relapsed PTCL should be considered for allogenic stem cell transplantation, if suitable (Lunning and Horwitz2013).
