Duodenal-type follicular lymphoma: A closer look

Radiation therapy (RT) alone can help control duodenal-type follicular lymphoma—a rare iteration of follicular lymphoma (FL) in western countries, but more common in Asian countries. The findings were recently published in Cancer Research and Treatment.

“There is still no consensus on the initial treatment, and clinical features including endoscopic findings are not familiar to most physicians,” wrote lead author Seok Jin Kim, MD, PhD, Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.

Originally, duodenal-type FL was considered a primary intestinal FL; however, the World Health Organization now considers it a subtype of FL because of its distinct clinical features. Duodenal-type FL displays similar pathological findings with those of nodal FL in terms of morphology and positivity for CD10 and Bcl-6 immunohistochemistry.

Results from gene expression analysis have shown that duodenal-type FL is more similar to mucosa-associated lymphoid tissue (MALT) lymphoma than it is to nodal FL. Furthermore, the clinical features of duodenal-type FL are more similar to MALT lymphoma than those of nodal FL due to its localization to the duodenum.

With these considerations in mind, newly diagnosed duodenal-type FL is initially treated with RT, akin to localized nodal FL. Limited, low-power research findings suggest that RT works to control disease in these patients, but no consensus on this approach exists. Questions remain as to the timing and target volume of RT.

Moreover, because duodenal-type FL is rare, little data exist regarding treatment outcomes, and many physicians are unfamiliar with its clinical symptoms and endoscopic features.

“We analyzed patients with duodenal-type FL who were consecutively treated with RT and report their clinical features including endoscopic findings and the treatment outcome,” the authors wrote.

In this retrospective study, Dr. Kim and colleagues examined 20 patients (median age 52; 70% women) diagnosed with duodenal-type FL via endoscopic biopsy between 2008 and 2017 for a median follow-up of 20 months. All patients were treated with RT on diagnosis, with intent to cure. After diagnosis, one patient received six cycles of CVP (cyclophosphamide, vincristine, and prednisone) chemotherapy, followed by RT 1.6 years later as salvage therapy.

In total, 18 of 20 patients (90%) had stage 1 disease at the level of the duodenum, and only one patient exhibited infiltration of the bone marrow. Only three patients presented with abdominal discomfort and dyspepsia at diagnosis, with 15 of 20 patients (75%) asymptomatic and diagnosed incidentally during routine medical examination.

In 19 of 20 patients (95%), the researchers noted a histological grade of 1. With respect to endoscopic findings, eight cases were diffuse nodular, eight cases were whitish granular, and four cases were mixed pattern.

In 17 of 20 patients, RT was administered at 24 Gy in 12 fractions, and 3 of 20 patients received between 30.6 and 36 Gy in 18 fractions. On endoscopic exam, 19 of 20 patients (95%) exhibited complete response, and all 20 patients survived without late toxicities secondary to radiation therapy.

In this study, the histological grade, stage distribution, prognostic risk measures, and response to RT were comparable to previous retrospective findings. The frequency of nodular or fine granular patterns on endoscopy was also similar to previous studies. Differences from previous studies included a higher number of female patients, a younger median age, and a higher incidence of abdominal pain.

The authors conceded that this study had limitations secondary to its retrospective design. For example, the staging work-up may have failed to expose the full burden of the disease, as the researchers themselves did not actually perform a full endoscopic examination of the duodenum.

“Duodenal-type FL had endoscopically unique findings and indolent clinical features,” concluded the authors. “RT alone could effectively control duodenal lesions, although a further study with longer follow-up duration is warranted to confirm our findings.”

To read more about this study, click here.