The follicular non-Hodgkin's lymphomas--I. The possibility of cure

Impact of age on long-term relative survival benefit of radiotherapy for early-stage grade I-II follicular lymphoma from the SEER database (2000-2015)

The aim of this study was to investigate the effect of age on long-term mortality and net survival benefit of radiotherapy (RT) for early-stage grade I-II FL. Five thousand three hundred and five patients with early-stage grade I-II FL in the SEER database (2000-2015) were identified. Primary therapy included RT alone (RT, 20.7%), chemotherapy alone (CT, 27.6%), combined modality therapy (CMT, 5.9%), and observation (45.8%). Inverse probability of treatment weighting (IPTW) was conducted to balance the treatment arms. Relative survival (RS), the standardized mortality ratio (SMR), and transformed Cox regression were used to compare survival differences between treatments. RT with or without CT had significantly higher 10-year OS (approximately 78%) and RS (>95%), but lower SMR (1.47-1.76), compared with CT (67.8%; 86.3%; 2.35; ps < .001), observation (70.2%; 91.2%; 1.82; ps < .05). RT was an independent predictor of better OS and RS in multivariate analyses (p < .001). No significant interaction between age and RT was identified for RS (Pinteraction = .509) or OS (Pinteraction = .769), indicating similar survival benefits across all-ages patients. RT was associated with long-term OS and net survival benefits in patients with early-stage grade I-II FL, irrespective of age.HighlightsThe pattern and incidence of mortality varied by age-group as elderly patients often die of other diseases other than FL beyond 5 years.Radiotherapy was associated with higher long-term OS/RS and better SMR compared with other approaches, regardless of age.

Additional therapy improves outcomes in completely resected, limited-stage follicular lymphoma

Patients with early-stage nodal follicular lymphoma (FL) may be rendered free of detectable disease by a diagnostic excisional biopsy. We reviewed the management and outcomes of 48 patients with FL, diagnosed from 2003-2013, treated at a single institution. The primary endpoints were local control (LC) and progression-free survival (PFS).Median age at diagnosis was 54.5 years (range 15-74 years). Forty-seven patients were stage I (97.9%); 15 patients (31.3%) had grade 3 disease. Initial management consisted of observation (12 patients; 25.0%), radiation therapy (RT) alone (12 patients; 25.0%), systemic therapy alone (9 cases; 18.8%), or both (15 patients; 31.3%). Median follow-up was 4.92 years (range 0.5-13.83 years). 4-year PFS and OS were 80.9% and 97.1%, respectively. Patients treated with additional therapy experienced significantly better 4-year LC (100% vs. 81.8%; p = .012) and 4-year PFS (86.7% vs. 63.6%; p = .006).Patients with completely resected limited-stage FL would benefit from therapy beyond excisional biopsy alone.

Outcome of patients with early-stage follicular lymphoma staged with 18F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) and treated with radiotherapy alone

PURPOSE/OBJECTIVE(S)

To evaluate the impact of positron emission tomography (PET) staging on overall survival (OS) and progression-free survival (PFS) in patients with early-stage (stages I and II) follicular lymphoma (ESFL) treated with radiation therapy alone.

MATERIALS/METHODS

Eighty-five patients with ESFL treated with curative-intent radiation therapy (RT) between December 2000 and May 2011 were identified. Of those, 13 who had no PET staging and 25 who received additional systemic therapy were excluded from the analysis. Thus, we analyzed 47 patients with PET-staged ESFL treated with definitive radiation therapy alone (dose > 23Gy). Tumour features, pre-treatment computed tomography (CT) and PET stage, dose fractionation, and radiation therapy field extent were recorded. The Kaplan-Meier method was used to estimate the OS and PFS. Patterns of failure were assessed as cumulative incidences assuming competing risks.

RESULTS

Median age was 57 years (range 24-83); 43% were females. Most were PET stage 1 (76.6%). Median maximum nodal diameter was 3 cm. Median pre-treatment lactate dehydrogenase (LDH) was 327.5 (range 123-607, upper normal limit = 220). Twenty-six patients (55.3%) had infra-diaphragmatic disease. All received 30-36Gy in 15-24 fractions, with 59.6% treated with involved-field radiation therapy (IFRT) techniques. There was no significant difference in PFS between CT stage I and stage II (HR 1.30 95% CI [0.25-6.72], p = 0.75) with a 5-year PFS of 77% and 78% respectively. However, stage I on PET staging had a significantly better PFS than stage II (HR 4.66 95% CI [1.15-18.8], p = 0.038), with 5-year PFS of 84% and 60% respectively. Ten patients had recurrent disease, with distant disease being the first site of failure in seven patients. Seven-year OS was 91% (95% CI 79-100) for the whole cohort.

CONCLUSION

FDG-PET should be considered an essential element in the evaluation of patients with ESFL being considered for RT.

Limited Stage Follicular Lymphoma: Current Role of Radiation Therapy

Radiation therapy (RT) alone has been considered for a long time as the standard therapeutic option for limited stage FL, due to its high efficacy in terms of local disease control with a quite significant proportion of “cured” patients (without further relapses at 10–15 years). Multiple therapeutic choices are currently accepted for the management of early stage FL at diagnosis, and better staging procedures as well as better systemic therapy partially modified the role of RT in this setting. RT has also changed in terms of prescribed dose as well as treatment volumes. In this review, we present and discuss the current role of RT for limited stage FL in light of the historical data and the modern RT concepts along with the possible combination with systemic therapy.

Treatment strategies in limited stage follicular NHL

Limited stage (I-II) follicular lymphoma is an uncommon entity, since most patients with this disease have generalized adenopathy (stage III) or bone marrow involvement (stage IV). Although patients who present with stage III-IV disease often are considered to be incurable, ~50% of patients with limited disease will enjoy long-term freedom-from progression, usually following treatment with radiation therapy. Relapse among these patients is uncommon after 10 years and exceedingly rare after 15 years. Radiation treatment is generally restricted to the involved nodal region(s) with modest (~5 cm.) extension proximally and distally. Radiation dose is generally 30 Gy, but may be boosted slightly (36 Gy total) in the presence of bulky disease. Randomized clinical trials have been insufficiently powered to define the value of any additional treatment beyond radiation therapy, although single arm studies suggest a benefit to the addition of chemotherapy. There have been no reported experiences with chemo-immunotherapy or radioimmunotherapy. Patients should be monitored during follow up to identify transformation to a more aggressive lymphoma.

Follicular lymphoma: a historical overview

Lymphoma was first described in 1862 and follicular lymphoma in 1925. Initially considered a benign disorder, and named Brill - Symmers disease after the authors of the original papers, it was rapidly recognized as a malignancy with a variable but often indolent course. Most of its clinical features were described by the early 1940s. Despite discussion about its cell of origin, and in contrast to many other lymphoma subtypes, follicular lymphoma could always be accurately recognized and diagnosed using light microscopy morphological features. B-cell origin was demonstrated in the 1970s and the important role of t(14;18) and bcl-2 gene rearrangement in the pathogenesis of follicular lymphoma was established shortly thereafter. The etiology of follicular lymphoma, the reason for marked geographic variation in its incidence, the role of alternative molecular pathways in its pathogenesis, and the cause for its variable clinical behavior all remain unknown. Several observations suggest an important role for the normal immune response in regulating the clinical behavior of follicular lymphoma. From the earliest descriptions, radiation therapy was shown to be very effective in follicular lymphoma, but not curative. Combination chemotherapy was tested in the 1970s, but despite high rates of response, there was only minimal impact on survival. Interferon combined with anthracycline based chemotherapy was the first treatment to improve survival, but was not widely adopted in the USA. Randomized studies have shown an impact of autologous transplantation on progression free survival. Allogeneic transplantation is a curative therapy, but is too toxic for widespread application. Targeted therapies, particularly rituximab have revolutionized the treatment of follicular lymphoma. A convergence of technological and biological advances will likely lead to further dramatic progress in the next decade. For the first time consistent improvements in survival of follicular lymphoma are reported.

Long-term outcome after radiotherapy alone for lymphocyte-predominant Hodgkin lymphoma

BACKGROUND

The curative potential of radiotherapy (RT) alone as initial treatment for patients with Stage I-II lymphocyte-predominant Hodgkin lymphoma (LPHL) has not been defined well.

METHODS

Two hundred two patients who were treated between 1969 and 1995 were evaluated in a retrospective, multicenter study.

RESULTS

Patient characteristics were as follows: The median age was 31 years, 75% of patients were male, 80% of patients had Ann Arbor Stage I disease, 1% of patients had bulky disease, 3% of patients had B symptoms, 1% of patients had extranodal involvement, and 80% of patients had supradiaphragmatic disease. The RT fields were a full mantle field in 52% of patients, less than a full mantle field in 24% of patients, an inverted-Y field in 17% of patients, less than an inverted-Y field in 3% of patients, and total lymph node irradiation in 3% of patients. The median dose was 36 Gray. The median follow-up was 15 years. The overall survival (OS) rate at 15 years was 83%, and freedom from progression (FFP) was observed in 82% of patients, including 84% of patients with Stage I disease and 73% of patients with Stage II disease. No recurrent LPHL and only 1 patient with non-Hodgkin lymphoma (NHL) were reported after 15 years. Adverse prognostic factors that were identified on multifactor analysis were as follows: for OS, age 45 years or older (P < 0.0005), the presence of B symptoms (P = 0.002), increasing number of sites (P = 0.015); for FFP, increasing number of sites (P = 0.002). No significant difference was found in FFP in a comparison of patients who received elective mediastinal RT with patients who did not receive mediastinal RT (P = 0.11). Causes of death at 15 years were LPHL in 3% of patients, NHL in 2% of patients, in-field malignancy in 2% of patients, in-field cardiac/respiratory in 4% of patients, and other in 6% of patients.

CONCLUSIONS

The current data suggested that RT potentially may be curative for patients with Stage I-II LPHL and raise the possibility that limited-field RT may be used without loss of treatment efficacy. Involved-field RT warrants further investigation for patients with early-stage LPHL.

Phase II study of ISIS 3521, an antisense oligodeoxynucleotide to protein kinase C alpha, in patients with previously treated low-grade non-Hodgkin's lymphoma

BACKGROUND

The purpose of this study was to assess the efficacy and safety of ISIS 3521, an antisense phosphorothioate oligonucleotide to protein kinase C alpha in patients with relapsed low-grade non-Hodgkin's lymphoma (NHL).

PATIENTS AND METHODS

Twenty-six patients received ISIS 3521 (2 mg/kg/day) as a continuous infusion over 21 days of each 28-day cycle.

RESULTS

The median age of the patients was 53 years (range 37-77). Histological subtypes were low-grade follicular lymphoma (n = 22) and B-cell small lymphocytic lymphoma (n = 4). Twenty-one (81%) had stage III/IV disease. The median number of previous lines of chemotherapy was two (range one to six). A total of 87 cycles of ISIS 3521 were administered. Twenty-three patients were assessable for response. Three patients achieved a partial response. No complete responses were observed. Ten patients had stable disease. Grade 3-4 toxicity was as follows: neutropenia (3.8%) and thrombocytopenia (26.9%).

CONCLUSIONS

ISIS 3521 has demonstrated anti-tumour activity in patients with relapsed low-grade NHL. There may be a potential role for this agent in combination with conventional chemotherapy for advanced low-grade lymphoma, and further trials are warranted.

Parametric mean survival time analysis in gastric cancer patients

BACKGROUND

The mean survival time (MS) has acquired increasing importance as an outcome indicator for patient care and technology assessment. The authors use lifelong follow-up data from gastric cancer patients to study whether the MS is predictable from 5-year follow-up information based on 2 parametric models.

METHODS

The authors used 3597 gastric cancer patients operated on between 1950 and 1969 to create 50 groups. For each group, the disease-related survival curve (DRSC) was estimated from the 5-year follow-up data using the Boag model. The MS for the group was then estimated by combining the DRSC with the survival curve for the age and sex-matched contemporaries (control group) based on the competing risk model. Alternatively, it was estimated by using the DRSC and the MS for the control group (the survival limit model). These predicted MS values were compared with the full follow-up observations.

RESULTS

Although individual prediction errors varied depending on the group size (63 to 3597 patients) and the length of MS (0.3 to 20.2 years), the mean prediction errors were reasonably small; the survival limit model overestimated MS by 4.7% (95% confidence interval [CI], 1.6 to 7.8) and the competing risk model by 3.2% (95% CI, 0.1 to 6.5).

CONCLUSIONS

MS for gastric cancer patients is parametrically predictable from 5-year follow-up data. This analysis should be applicable to other diseases showing log-normal failure time distributions.

Long-term follow-up of a prospective study of combined modality therapy for stage I-II indolent non-Hodgkin's lymphoma

PURPOSE

Standard therapy for patients with stage I-II indolent lymphoma has been involved-field radiation therapy (IF-XRT), which achieves 10-year disease-free survival in 40% to 50% of patients, with many of these patients cured. We investigated the potential for combined-modality therapy to increase the disease-free survival for such patients.

PATIENTS AND METHODS

A total of 102 eligible patients with stage I-II low grade lymphoma (International Working Formulation criteria) were enrolled from 1984 to 1992. Treatment comprised 10 cycles of risk-adapted chemotherapy (cyclophosphamide, vincristine, prednisone, bleomycin [COP-Bleo], and with doxorubicin added for some [CHOP-Bleo]) and 30 to 40 Gy IF-XRT.

RESULTS

The patients' median age was 56 years (range, 28 to 77), with follicular histology in 83%, bulky disease (>/= 5 cm) in 24%, and stage II in 52%. There were no treatment-related deaths and 99% of patients attained complete remission. With a median follow-up of 10 years, the 10-year time to treatment failure and overall survival were 76% and 82%, respectively. For patients with follicular lymphoma, these figures were 72% and 80%, respectively. The only factor associated with treatment failure, for follicular lymphoma patients, was stage-modified International Prognostic Factors Index score (P =.02). None of 17 patients with diffuse small lymphocytic or mucosa-associated lymphoid tissue histology have relapsed. Elevated serum beta2-microglobulin was associated with shorter survival (P <.0001). The 10-year survival after relapse was 46%. There have been two cases of myelodysplasia and 12 other new malignancies, including four arising within radiation fields.

CONCLUSION

With prolonged follow-up, combined-modality therapy with risk-adapted COP-/CHOP-Bleo and IF radiation has attained higher rates of disease control and survival than previously reported with IF-XRT alone. This apparent improvement is being further explored in an ongoing randomized trial.

Long-term results with radiotherapy for Stage I-II follicular lymphomas

PURPOSE

To analyze the long-term results with radiotherapy (RT) for early-stage, low-grade follicular lymphomas.

METHODS AND MATERIALS

From 1960 to 1988, 80 patients with Stage I (n = 33) or II (n = 47), World Health Organization Grade 1 (n = 50) or 2 (n = 30) follicular lymphoma were treated with RT. The lymph nodes or spleen were involved in 97% of cases. The maximal tumor sizes ranged from 0.5 to 11.0 cm (median 2.0). The RT fields encompassed only the involved Ann Arbor nodal region (involved-field RT) in 9% of the patients. The fields also included 1-3 adjacent, grossly uninvolved nodal regions (regional RT) in 54% of patients but were smaller than mantle or whole abdominopelvic fields. Mantle or whole abdominopelvic fields encompassing up to 6 grossly uninvolved regions (extended-field RT) were used in the remaining 37% of patients. The total RT doses ranged from 26.2 to 50.0 Gy given in daily 1.0-3.0-Gy fractions.

RESULTS

The follow-up of the surviving patients ranged from 3.5 to 28.7 years (median 19.0). No recurrences were found >17.0 years after RT, with 13 patients free of disease at their last follow-up visit 17.6-25.0 years after treatment. In 58% of cases, death was not from follicular lymphoma. The 15-year local control rate was 100% for 44 lymphomas <3.0 cm treated with only 27.8-30.8 Gy (median 30.0 in 20 fractions). Progression-free survival was affected by the maximal tumor size at the start of RT (15-year rate 49% vs. 29% for lymphomas <3.0 cm vs. > or =3.0 cm, respectively, p = 0.04) and Ann Arbor stage (15-year rate 66% vs. 26% for Stages I and II, respectively, p = 0.006). Ann Arbor stage also affected the cause-specific survival (15-year rate 87% vs. 54% for Stages I and II, respectively, p = 0.01). No significant difference was found in overall survival between those treated with extended-field RT and those treated with involved-field RT or regional RT (15-year rate 49% and 40%, respectively, p = 0.51). The 15-year incidence rate of Grade 3 or greater late complications according to the Subjective, Objective, Management, and Analytical scale in patients treated with 26.2-30.8 Gy vs. 30.9-50.0 Gy was 0% and 6%, respectively.

CONCLUSIONS

RT can cure approximately one half of Stage I and one quarter of Stage II, World Health Organization Grade 1 or 2 follicular lymphomas. Follicular lymphomas <3.0 cm can be controlled locally with doses of 27.8-30.8 Gy, and there is a trend toward a higher incidence of late complications with doses of >30.8 Gy. Doses of 25-30 Gy delivered in 15-20 fractions should be examined prospectively in patients with follicular lymphomas of <3.0 cm.

Testing for the presence of cured patients: a simulation study

An important but difficult problem in clinical trials is to determine the presence of cured patients when long-term survivors are observed. The likelihood ratio test has been studied for this purpose in the gamma mixture model. However, its asymptotic null distribution is not readily available due to a violation of boundary conditions in the standard asymptotic theory. In this paper, a simulation study is employed to examine a proposed asymptotic null distribution of the likelihood ratio test. We find that the distribution can also be used to approximate the asymptotic null distribution of the likelihood ratio test in the Weibull and log-normal mixture models when the censoring rate is not too light. However, the simulation study also shows that null distribution of the likelihood ratio test deviates significantly from the suggested distribution under moderate sample sizes when the censoring rate is small or the hazard rate is large. Consequently caution is needed in this case to determine the presence of cured patients. Finally, the results are used to confirm the presence of cured patients in a leukaemia study.

Follicular lymphomas--a review of treatment modalities

Follicular lymphoma is the most common low-grade non Hodgkin's lymphoma and represent an homogeneous entity as defined by pathological, molecular and clinical data. This indolent disease is characterised by a slow growth pattern with possible spontaneous regression, is often disseminated but remains incurable with available treatments when disseminated. For localised stages, involved field radiotherapy remains the standard choice but other approaches remain to be investigated. In advanced disease, chemotherapy has been demonstrated to produce high response rates but recent trials with new treatment strategies including interferon and monoclonal antibodies may improve the current situation. In this article, we will review treatment of follicular lymphomas, specially emphasising published phase III trials.

A nonparametric mixture model for cure rate estimation

Nonparametric methods have attracted less attention than their parametric counterparts for cure rate analysis. In this paper, we study a general nonparametric mixture model. The proportional hazards assumption is employed in modeling the effect of covariates on the failure time of patients who are not cured. The EM algorithm, the marginal likelihood approach, and multiple imputations are employed to estimate parameters of interest in the model. This model extends models and improves estimation methods proposed by other researchers. It also extends Cox's proportional hazards regression model by allowing a proportion of event-free patients and investigating covariate effects on that proportion. The model and its estimation method are investigated by simulations. An application to breast cancer data, including comparisons with previous analyses using a parametric model and an existing nonparametric model by other researchers, confirms the conclusions from the parametric model but not those from the existing nonparametric model.

What is the prognosis for patients who relapse after primary radiation therapy for early-stage low-grade follicular lymphoma?

PURPOSE

To investigate the potential for long-term survival for patients who relapsed after primary radiation therapy (RT) for early-stage low-grade follicular lymphoma and to assess the relative importance of prognostic factors.

METHODS AND MATERIALS

Records were reviewed for 79 patients with stage I (n = 32) and II (n = 47) follicular small cleaved cell (fsc, n = 48) and follicular mixed small cleaved cell and large-cell (fmx, n = 31) lymphoma who relapsed after radical RT at Stanford University. Most patients had received doses of 35 to 45 Gy to involved (n = 30) or extended fields (n = 39) or total/subtotal lymphoid irradiation (n = 9).

RESULTS

Median time to relapse was 2 years. Most relapses were detected on history (30%) or physical examination (66%). Positive relapse investigations included lymphangiogram (n = 19), chest radiograph (n = 5), and bone marrow biopsy (n = 6). Known extent of relapsed disease was: stage I, n = 30; stage II, n = 26; stage III, n = 10; and stage IV, n = 8. Patients were managed with "watchful waiting" (37%), further RT (39%), chemotherapy [CT, (17%)], or RT + CT (5%). Actuarial survival rates after relapse at 5, 10, 15, and 20 years were 56%, 35%, 17%, and 17% respectively. Median survival was 5.3 years after relapse. Median survival for relapse stage I, II, III, and IV was 10.2, 5.5, 3.0, and 1.1 years respectively. Progression-free survival rates at 5, 10, 15, and 20 years after relapse were 44%, 22%, 22%, and 22% respectively. Factors associated with reduced survival were increasing age, increasing relapse stage, symptoms, histologic transformation and > or = 3 relapse sites. Survival was the same for initial management with "watchful waiting" or RT.

CONCLUSION

Approximately 20% of patients experienced prolonged survival after relapse. Younger, asymptomatic patients with stage I-II relapsed disease had the best outcome but results were inferior to those for newly diagnosed stage I-II disease.

A generalized F mixture model for cure rate estimation

Cure rate estimation is an important issue in clinical trials for diseases such as lymphoma and breast cancer and mixture models are the main statistical methods. In the last decade, mixture models under different distributions, such as exponential, Weibull, log-normal and Gompertz, have been discussed and used. However, these models involve stronger distributional assumptions than is desirable and inferences may not be robust to departures from these assumptions. In this paper, a mixture model is proposed using the generalized F distribution family. Although this family is seldom used because of computational difficulties, it has the advantage of being very flexible and including many commonly used distributions as special cases. The generalised F mixture model can relax the usual stronger distributional assumptions and allow the analyst to uncover structure in the data that might otherwise have been missed. This is illustrated by fitting the model to data from large-scale clinical trials with long follow-up of lymphoma patients. Computational problems with the model and model selection methods are discussed. Comparison of maximum likelihood estimates with those obtained from mixture models under other distributions are included.

[Radiotherapy of follicle center lymphoma. Results of a German multicenter and prospective study. Members of the Study Group "NHL-early stages"]

PURPOSE

Follicle centre lymphoma grade I, II (REAL) or centroblastic-centrocytic lymphoma (Kiel classification) present a well defined clinical entity from a clinical point of view. These lymphomas are not curable by chemotherapy in early or advanced stages. They are treated by radiation therapy in early stages, but up to now the curative potency of radiotherapy has not been confirmed by prospective clinical trials.

PATIENTS AND METHODS

Between January 1986 and August 1993 117 adults with follicle centre lymphoma were recruited from 24 institutions to enter the multicentric prospective, not randomised clinical trial. Patients with histologically proven nodal follicle centre lymphoma of stages I, II and limited III were included. They were treated by a standardised radiotherapy regimen, in stage I by extended field and in stages II and III by total nodal irradiation. Dose per fraction was 1.8 to 2.0 Gy, in the abdominal bath 1.5 Gy up to a total dose of 26 Gy in adjuvant situation and 36 Gy to enlarged lymphoma.

RESULTS

All patients developed a complete remission at the end of radiotherapy. Median follow-up is 68 months. Overall survival of all patients in 86 +/- 3% at 5 and 8 years. Stage adjusted survival at 5 and 8 years was 89% for stage I, 86% for stage II and 81% for III. Patients in stages I and II < 60 years had survival rates of 94% at 5 and 8 years, patients > 60 years 63% (p < 0.0001). Recurrence free survival of all patients is 70% at 5 and 60 +/- 5% at 8 years. The number of recurrences is high with 29% at 5 and 41% at 8 years. All recurrences were seen within 7 years. The probability of localised nodal in-field recurrences is 11% and 22% at 5 and 8 years, respectively. Adverse prognostic factors were identified by multivariate analysis: age > 60 years, treatment breaks > or = 7 days and dose deviations > 20% from prescribed doses. Acute side effects of extended field irradiation were moderate.

CONCLUSIONS

On the basis of these results radiotherapy is a potentially curative therapeutic approach in stages I, II and limited III of follicle centre lymphoma. The optimal technique is total lymphoid irradiation with doses of 30 Gy in the adjuvant situation and 40 to 44 Gy in enlarged lymphomas. The number of local recurrences leads to the assumption, that the extension of radiotherapy to the total lymphoid system might reduce their frequency.

Extended field and total central lymphatic radiotherapy in the treatment of early stage lymph node centroblastic-centrocytic lymphomas: results of a prospective multicenter study. Study Group NHL-frühe Stadien

BACKGROUND

A prospective multicenter trial was performed to evaluate survival, patterns of relapse, and toxicity for clinically staged patients with lymph node centroblastic-centrocytic (cb/cc) lymphomas in Stages I-IIIA after large extended field irradiation (EFI) or total central lymphatic irradiation (TCLI).

METHODS

Between January 1986 and August 1993, 117 adults with clinical Stage I-IIIA lymph node cb/cc lymphoma (Kiel classification) were recruited. Patients in Stages I or II with mediastinal, hilar, periaortic, iliac, or mesenteric involvement and in Stage IIIA received TCLI, whereas patients with more peripherally located cb/cc lymphomas were treated with EFI. TCLI and EFI were administered to a total dose of 26 gray (Gy) with 2 Gy per daily fraction, with the exception of the whole abdomen, which was irradiated to a total dose of 25.5 Gy with 1.5 Gy per fraction. A boost of 10 Gy with 2 Gy per fraction was administered to enlarged and involved lymph nodes at the start of radiotherapy.

RESULTS

Sixty, 40, and 17 patients had Stage I, II, and limited IIIA disease (no bulk and less than 6 involved lymph node regions), respectively. Overall survival was 86% at 5 and 7 years; median follow-up was 68 months. The probabilities of relapse at any site, recurrences in lymph nodes, and in-field lymph node recurrences after TCLI were 17% in Stage I; 56%, 43%, and 40% in Stage II, respectively; and 44%, 35%, and 35% in Stage IIIA, respectively. The risk of disseminated extralymphatic relapses was 9% at 7 years. The most important adverse prognostic factor for in-field lymph node recurrences was a deviation of >20% from the assigned total radiation dose. After EFI, patients in Stage I had a significantly lower risk of recurrences in adjuvant irradiated lymph node regions than in unirradiated lymph node regions. Acute toxicity of EFI and TCLI was moderate.

CONCLUSIONS

In-field lymph node recurrences remained the main risk after TCLI, and a deviation of >20% from the assigned radiation dose was the major risk factor for in-field recurrences. From these data, a total dose of 40-44 Gy in conventional fractionation for the treatment of macroscopic cb/cc lymphomas and 30 Gy for the treatment of subclinical disease is recommended. A randomized study comparing TCLI with EFI is now being organized by this group.

Overview of treatment of localized low-grade lymphomas

The results of treatment of localized low-grade lymphoma have been reviewed with particular emphasis on the results of long-term follow-up of patients treated with radiation therapy at Stanford University. These data and results from numerous other centers suggest that 40% to 50% of patients with stage I and II follicular low-grade lymphomas can expect to achieve clinical cure of their disease with radiation therapy. Randomized trials published to date do not support the use of adjuvant chemotherapy. Although a policy of initial observation with deferral of treatment until the occurrence of disease progression is a well established approach to patients with advanced disease, no randomized studies exist that support this as a safe alternative to radiation therapy for early stage disease. New systemic therapies are required for the treatment of occult disease to prevent the occurrence of relapse outside of irradiated volumes.