# Radiation Oncology/NHL/Cutaneous B-cell lymphoma

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Primary Cutaneous B-Cell Lymphoma (PCBCL)
    For cutaneous T-cell lymphomas, see Mycosis fungoides

## Pathology

* B-cell lymphomas 20-25% of all cutaneous lymphomas
* Subtypes: primary cutaneous follicular center-cell lymphoma (PCFCCL), primary cutaneous immunocytoma (PCI), primary cutaneous large B-cell lymphoma (PCLBCL) of the leg
WHO Classification
* Most common histology: diffuse large B-cell lymphoma
EORTC Classification
* Note: in the EORTC, diffuse large B-cell lymphomas of non-leg site are classified as follicle center cell (i.e., considered indolent instead of aggressive)

## Epidemiology

* Overall (data from SEER, PMID 15908651)
** Mean age 64 yrs. Male 54%.
** Incidence increasing
** Histology (WHO): DLBCL in 33%, NOS 24%, follicular 17%, MZL 8%
** Site: head or neck 50%, trunk 19%, arm 12%, leg 11%, disseminated 8%
* PCFCCL
** Localized to skin; rarely disseminate to extracutaneous sites
** Usually involve head or trunk
** 5-yr OS > 95%
* PCI
** Usually involve arms and legs
** Excellent prognosis
* PCLBCLs of the leg
** Affects elderly patients
** More often involves extracutaneous sites
** Poor prognosis: 5-yr OS 58%
* SEER; 2008 (1973-2004) PMID 18349400 -- "Analysis of primary CD30+ cutaneous lymphoproliferative disease and survival from the Surveillance, Epidemiology, and End Results database." (Yu JB, J Clin Oncol. 2008 Mar 20;26(9):1483-8.)
** SEER review. 268 cases; 58% males, 87% white. 157 (59%) primary localized PCLPD
** Outcome: 3-year OS 81% vs. population-matched OS 87%; 5-year DSS 92%. H&N worse outcome
** Conclusion: Rare disease, with excellent OS; more common in white men, H&N sites worse survival

## Prognostic Index

* Yale; 2005 - PMID 15908651 — "The cutaneous B-cell lymphoma prognostic index: a novel prognostic index derived from a population-based registry." (Smith BD, J Clin Oncol. 2005 May 20;23(15):3390-5.)
** From SEER registry (1973-2001). 1343 cases. Histology according to WHO classification. Developed prognostic index based on histology and site.
| CBCL-PI Group | Histology | Site | 5-yr OS |
| IA | Indolent (follicular, marginal zone, small lymphocytic, lymphoplasmacytic) | Any | 81% |
| IB | Diffuse large B-cell | Favorable (head/neck, arm) | 72% |
| II | DLBCL | Unfavorable | 48% |
| II | Immunoblastic diffuse large B-cell | Favorable | 48% |
| III | Immunoblastic diffuse large B-cell | Unfavorable | 27% |

## Outcomes

* Yale (1990-2002)
** Retrospective, 34 pts. Treated with RT as primary treatment; Median dose 40 Gy (range 20-48 Gy). No systemic disease.
** Comparison of EORTC and WHO pathologic classification systems, which differ in characterizing these lesions, and therefore recommendations for treatment may differ (based on characterization as indolent or aggressive lymphomas)
** 2004 PMID 14966086 -- "Primary cutaneous B-cell lymphoma treated with radiotherapy: a comparison of the European Organization for Research and Treatment of Cancer and the WHO classification systems." (Smith BD, J Clin Oncol. 2004 Feb 15;22(4):634-9.) -- Median f/u 3.4 yrs
*** 5-yr OS 96%, RFS 55%, LR-free survival 81%, extracutaneous relapse-free survival 79%. OS and RFS was 67% and 33% for leg-type DLBCL and 100% and 62-73% for other types
*** 62% (8/13) of initial relapses confined to skin (localregional or distant), 24% (8/34) of all pts. Distant relapse (+/- skin) in 38% (5/13) of all relapses or 15% (5/34) of all pts.
*** Pathologic: 68% of lesions classified as follicle center cell (i.e. indolent) by EORTC criteria are classified as DLBCL (i.e. aggressive) by WHO system, but the biologic behavior is indolent.
*** Increased risk of LR with dose < 36 Gy: 5-yr LR-free survival 50% (< 36 Gy) vs 90% (>= 36 Gy).
*** Conclusion: 40 Gy dose is recommended. Worse outcome for leg type; however, for the other lesions, DLBCL histology appears more indolent than in nodal lymphomas.
PCLBCL:
* European multicenter (1979-98) - PMID 11504742, 2001 — "Prognostic factors in primary cutaneous large B-cell lymphomas: a European multicenter study." Grange F et al. J Clin Oncol. 2001 Aug 15;19(16):3602-10.
** Retrospective. 48 pts with PCLBCL of leg; 97 with PCFCCL.
** On multivariate analysis, worse outcomes for location on leg, multiple lesions, and round cell morphology.

## Treatment

Solitary lesion: Most often presents as a solitary lesion (~85%). Radiotherapy is preferred treatment for solitary lesions. Dose 40 Gy.
Multifocal disease:
* Netherlands (1985-97) - PMID 10561311, 1999 — "Treatment of multifocal primary cutaneous B-cell lymphoma: a clinical follow-up study of 29 patients." Bekkenk MW et al. J Clin Oncol. 1999 Aug;17(8):2471-8.
** Retrospective. Included 29 pts who had involvement of >= 2 nonadjacent skin areas that did not fit into one radiation field without extracutaneous disease (14% of patients seen at this center). Pts treated with either chemotherapy (CHOP in most) or RT.
** 16 pts had PCFCCL, 8 PCI, 5 PCLBCL of leg.
** Excellent results in PCFCCL or PCI for either chemo or RT. All pts with PCLBCL relapsed with extracutaneous disease.