Long-term outcomes for patients with limited stage follicular lymphoma: involved regional radiotherapy versus involved node radiotherapy

90Y-ibritumomab tiuxetan radiotherapy as first-line therapy for early stage low-grade B-cell lymphomas, including bulky disease

(90) Y-ibritumomab-tiuxetan ((90) YIT) was used as a first-line therapy for patients with early-stage follicular lymphoma (FL) or marginal zone B-cell lymphoma (MZL). Thirty-one patients were treated, with an overall 3-month response rate of 100% (68% complete response, 29% unconfirmed complete response and 3% partial response). At a median follow-up of 56 months, ten patients (32%) had disease relapse or progression. The progression-free rates at 3 and 5 years were lower in males, patients with FL, stage II disease and non-bulky disease, although they did not reach statistical significance. Grade 3-4 neutropenia, thrombocytopenia and anaemia were 61%, 35%, and 3%, respectively. (90) YIT was well tolerated, including in those patients over 60 years old, and achieved high response rates in patients with early-stage low-grade B-cell lymphomas. Bulky disease did not adversely affect tumour response.

Radiotherapy of follicular lymphoma: updated role and new rules

Radiation is established as one of the most powerful, highly effective treatments for non-Hodgkin lymphoma (NHL). Unfortunately, in recent years the medical oncology community has improperly underutilized radiotherapy (RT) in the management of NHL. Replacing RT with longer chemotherapy and/or immunotherapy may not necessarily be a good alternative approach and may lead to suboptimal outcome and more toxicity, particularly in patients with localized disease. Some misconceptions regarding the use of RT emanated from the ways RT has been utilized in the past-as a single therapy and in high doses and large fields. Major developments in imaging technology, radiation planning concepts, and RT precision and delivery have been revolutionized RT for NHL over the past two decades. Modern proper administration should result with very minimal acute or late side effects. Some of the controversial issues of the use of RT borrowed from Hodgkin lymphoma, such as risk of secondary tumors, are irrelevant to patients with NHL but cause unnecessary patient and physician scare. Many lymphoma types are notoriously sensitive to RT, especially the indolent types. When localized, like in most marginal zone lymphoma (MZL) and almost a third of follicular lymphomas (FL), RT is potentially curative, even with low dose and small volumes. In more aggressive lymphomas, RT often is an effective consolidation after chemotherapy in complete or even incomplete responders. It also is an important component of salvage and palliation. In older patients, RT is particularly valuable, because chemotherapy tolerance and salvage options may be limited. The International Lymphoma Radiation Oncology Group (ILROG) developed and published modern guidelines for using RT in NHL, including FL. The guidelines emphasize the new concept of RT field: involved site radiotherapy (ISRT). These modern ILROG principles and several relevant studies that looked into the proper integration of RT in the management of NHL patients are the focus of this manuscript.

How we manage follicular lymphoma

Major changes have taken place within the last few years in the management of follicular lymphoma (FL) leading to substantial improvement in prognosis and overall survival. For some patients with limited disease stages I and II, radiotherapy may be associated with durable responses; however, it is unclear whether patients are cured and new approaches such as the combination of irradiation with rituximab or even single-agent rituximab need to be explored. Whereas watch and wait is the current standard for stage III and IV disease with low tumour burden, better indices are warranted to potentially select patients for whom early intervention is preferred. For advanced stages with a high tumour burden, immunochemotherapy followed by 2 years of rituximab maintenance is widely accepted as standard therapy, although re-treatment at recurrence may be an alternative option. Highly attractive new therapeutic options have recently arisen from new antibodies, and from new agents targeting oncogenic pathways such as B-cell receptor signalling pathways or inhibition of bcl 2. Furthermore, immunomodulatory drugs may add to the therapeutic armamentarium and may lead to 'chemotherapy-free' therapies in the near future. Hence, the management of FLs has become a moving target and the hope is justified that the long-term perspectives of patients suffering from the disease will be further improved in the near future.

Current role of FDG PET/CT in lymphoma

The management approach in Hodgkin's (HL) and high-grade non-Hodgkin's lymphomas (NHL) has shifted towards reducing the toxicity and long-term adverse effects associated with treatment while maintaining favorable outcomes in low-risk patients. The success of an individualized treatment strategy depends largely on accurate diagnostic tests both at staging and during therapy. In this regard, positron emission tomography (PET) using fluorodeoxyglucose (FDG) with computed tomography (CT) has proved effective as a metabolic imaging tool with compelling evidence supporting its superiority over conventional modalities, particularly in staging and early evaluation of response. Eventually, this modality was integrated into the routine staging and restaging algorithm of lymphomas. This review will summarize the data on the proven and potential utility of PET/CT imaging for staging, response assessment, and restaging, describing current limitations of this imaging modality.

Reduction of the treated volume to involved node radiation therapy as part of combined modality treatment for early stage aggressive non-Hodgkin's lymphoma

BACKGROUND AND PURPOSE

This retrospective study investigated whether focused involved node radiation therapy (INRT) can safely replace involved field RT (IFRT) in patients with early stage aggressive NHL.

PATIENTS AND METHODS

We included 258 patients with stage I/II aggressive NHL who received combined modality treatment (87%) or primary RT alone (13%). RT consisted of a total dose of 30-40 Gy in 15-20 fractions IFRT or INRT. We compared survival, relapse pattern, radiation-related toxicity and quality of life for both RT techniques.

RESULTS

Type of RT was not related to the outcome in either the uni- or multivariate survival analysis. Relapses developed in 59 of 252 patients (23%) of which 47 (80%) were documented as distant recurrence only. Failure of the INRT technique was noted in one patient. There was no significant difference in acute radiation-related toxicity between RT-groups but IFRT showed a significantly higher incidence of higher grade toxicities. Patients treated with INRT had a significantly better physical functioning and global quality of life compared to the IFRT group.

CONCLUSIONS

Given the retrospective nature of this study, no solid conclusions can be drawn. However, in view of the equivalent efficacy and more favorable toxicity profile, the replacement of IFRT by INRT in combination with chemo-(immuno)-therapy looks very attractive for patients with early stage aggressive NHL.

Early stage follicular lymphoma: what is the clinical impact of the first-line treatment strategy?

BACKGROUND

Less than 20% of patients with follicular lymphoma (FL) present with Ann Arbor Stage I or II disease at diagnosis. Numerous therapeutic options exist, however radiation therapy is considered the standard of care for early-stage disease based on single-institution or retrospective series. Our aim was to revisit the outcome of patients with localized FL in the rituximab era.

PATIENTS AND METHODS

We analyzed the characteristics and outcomes of 145 early-stage FL patients, who were retrospectively divided into six groups according to their initial treatment: watchful waiting (WW), chemotherapy alone (CT), radiotherapy alone (RT), combined radiotherapy and chemotherapy (RT-CT), rituximab alone (Ri), and immunochemotherapy (Ri-CT).

RESULTS

Of the 145 patients, 84 (57.9%) had stage I disease and 61 (42.1%) stage II. The complete response (CR) rate varied from 57% for the Ri group to 95% for the RT-CT group. Overall survival (OS) at 7.5 y of patients treated after 2000 was better than that of those treated prior to 2000. OS did not significantly differ from one treatment to another. In contrast, a significant difference was found for progression-free survival (PFS) at 7.5 y, which favored Ri-CT (60%) therapy versus the others (p=0.00135).

CONCLUSION

Delayed therapy initiation was associated with a similar OS than that observed in patients receiving immediate intervention. The "watchful waiting" strategy may thus be proposed as first-line therapy, similar to stage III and IV FL patients with a low tumor burden. However, when treatment is required, immunochemotherapy appears to be the best option.

Incidence of transformation to aggressive lymphoma in limited-stage follicular lymphoma treated with radiotherapy

BACKGROUND

The established treatment of limited-stage follicular lymphoma is radiotherapy (RT). There is an inherent risk of transformation of follicular lymphoma to aggressive lymphoma; however, the frequency and impact on the outcome are unknown in limited-stage patients.

MATERIALS AND METHODS

We identified 237 patients with limited-stage follicular lymphoma treated with curative intent RT. Cases were reviewed to determine the frequency of transformation and subsequent survival.

RESULTS

With a median follow-up of 7.4 years, the 10-year risk of transformation was 18.5%. With a median follow-up after transformation of 4.7 years, the 3-year post-transformation progression-free survival (PFS) and overall survival (OS) were 42% and 44%, respectively. The addition of rituximab improved the 3-year post-transformation PFS and OS compared with combination chemotherapy alone (78% versus 15%, P < 0.00001) and (87% versus 38.5%, P < 0.00001), respectively. In multivariate analysis, only rituximab was associated with OS [HR 0.07 (95% CI 0.015-0.312, P = 0.001)] and PFS [HR 0.19 (95% CI 0.55-0.626, P = 0.007)] following transformation.

CONCLUSIONS

There is a moderate risk of transformation in limited-stage follicular lymphoma treated with curative intent RT, and it substantially impacts outcome in these patients. Treatment with rituximab at the time of transformation appears to improve survival in this otherwise poor-risk population.

Early stage follicular lymphoma, current management and controversies

PURPOSE OF REVIEW

In this article, we focus on the epidemiology, outcomes, and treatment options of early stage follicular lymphoma.

RECENT FINDINGS

Radiation therapy has been the predominant treatment for patients with early stage follicular lymphoma for decades. It is associated with a 10-year progression-free survival of 45-60%, thought to represent cures in this otherwise incurable disease with conventional modalities. Limiting the radiation field and dose does not diminish outcomes. On the contrary, the addition of chemotherapy does not benefit this patient population as a whole. The use of polymerase chain reaction for Bcl-2 gene rearrangements to detect molecular disease, however, may identify patients with early occult disseminated disease, who are at risk for relapse and would benefit from the addition of systemic therapy. For patients in whom radiation would be too toxic or prefer to not have radiation, observation is a reasonable alternative and a proportion of patients observed do not require therapy for a number of years. Despite the potential cures achieved by radiation therapy, a minority of patients in the United States receive such therapy; the majority are instead observed or treated with chemoimmunotherapy.

SUMMARY

Patients with early stage follicular lymphoma enjoy excellent outcomes following definitive radiation therapy, many of whom may even be cured. The addition of other therapies has not enhanced cure rates but identifying patients at greatest risk for disease relapse may change this paradigm. Despite the proven success of radiation, the majority of early stage follicular lymphoma patients in the United States do not receive radiation.

Oxidative stress due to radiation in CD34(+) hematopoietic progenitor cells: protection by IGF-1

Radiation exerts direct as well as indirect effects on DNA through the generation of reactive oxygen species (ROS). Irradiated hematopoietic progenitor cells (HPCs) experience DNA strand breaks, favoring genetic instability, due to ROS generation. Our aim was to study the effect of a range of radiation doses in HPCs and the possible protective mechanisms activated by insulin-like growth factor-1 (IGF-1). ROS generation was evaluated, in the presence or absence of IGF-1 in liquid cultures of human HPCs-CD34(+) irradiated with 1-, 2- and 5-Gy X-rays, using a flow cytometry assay. Manganese superoxide dismutase (MnSOD) expression was studied by western blot analysis and visualized by an immunofluorescence assay. Apoptosis was estimated using the following assays: Annexin-V assay, DNA degradation assay, BCL-2/BAX mRNA and protein levels and caspase-9 protein immunofluorescence visualization. Viability and clonogenic potential were studied in irradiated HPCs. The generation of superoxide anion radicals at an early and a late time point was increased, while the hydrogen peroxide generation at a late time point was stable. IGF-1 presence further enhanced the radiation-induced increase of MnSOD at 24 h post irradiation. IGF-1 inhibited the mitochondria-mediated pathway of apoptosis by regulating the m-RNA and protein expression of BAX, BCL-2 and the BCL-2/BAX ratio and by decreasing caspase-9 protein expression. IGF-1 presence in culture media of irradiated cells restored the clonogenic capacity and the viability of HPCs as well. In conclusion, IGF-1 protects HPCs-CD34(+) from radiation effects, by eliminating the oxidative microenvironment through the enhancement of MnSOD activation and by regulating the mitochondria-mediated pathway of apoptosis.

The composition of the microenvironment in follicular lymphoma is associated with the stage of the disease

The role of regulatory and follicular helper T-cells as prognostic markers in follicular lymphoma was evaluated within the setting of prospective, randomized trials because the previously published results were contradictory. Two hundred sixty-four diagnostic tissue specimens from patients suffering from follicular lymphoma who received therapy within prospective randomized trials of the German Low Grade Lymphoma Study Group were analyzed immunohistochemically for FoxP3 and PD-1 expression to detect regulatory and follicular helper T-cells, respectively. We did not find any correlation between the content of regulatory and follicular helper T-cells and the time to treatment failure or overall survival in patients with advanced stages of follicular lymphoma in need of treatment. However, a perifollicular pattern of regulatory T-cells was associated with a poorer prognosis. The content of regulatory T-cells was positively and the content of follicular helper T-cells inversely correlated with a higher stage of the disease at diagnosis, implying that the microenvironment changes during tumor dissemination. This finding is independent of any therapy administered and needs to be considered when possible biomarkers related to the microenvironment of follicular lymphoma are studied.