The levels of evidence (I–IV) and strength of recommendations (A–C) are defined at the end of the "Major Recommendations" field.
Solitary Bone Plasmacytoma (SBP)
Diagnosis and Investigation of Solitary Bone Plasmacytoma
Diagnostic criteria
Recommended diagnostic criteria are summarized in the table below, titled "Recommended diagnostic criteria for solitary bone plasmacytoma (SBP) and extramedullary plasmacytoma (SEP)." Based on the data discussed above, the following criteria are recommended:
- Single area of bone destruction due to clonal plasma cells
- Histologically normal marrow aspirate and trephine (<5% plasma cells)
- Normal results on skeletal survey, including radiology of long bones
- No anaemia, hypercalcaemia or renal impairment due to plasma cell dyscrasia
- Absent or low serum or urinary level of monoclonal immunoglobulin (level of >20 g/l suspicious of multiple myeloma (MM))
- No additional lesions on magnetic resonance imaging (MRI) scan of the spine (see below for criteria of involvement)
Pathology review
Solitary bone plasmacytoma is generally diagnosed by biopsy or fine needle aspiration. Percutaneously guided biopsy of the spine is usually possible either by fluoroscopy or computed tomography (CT). As these tumours are rare, pathology review by a histopathologist with a special interest in either bone tumours or lymphoproliferative disorders is strongly recommended.
Further investigations
The following investigations should be performed in all patients:
- Full blood count
- Biochemical screen including electrolytes and corrected calcium
- Serum immunoglobulin levels
- Serum and urine protein electrophoresis and immunofixation
- Full skeletal survey, including standard X-rays of the skeleton including lateral and anteroposterior cervical, thoracic and lumbar spine, skull, chest, pelvis, humeri and femora
- MRI of thoracic and lumbar spine
- Bone marrow aspirate and trephine
Additional investigations may be useful in selected patients, including
- MRI of pelvis, proximal femora and humeri
- Immunophenotyping and molecular assessment of bone marrow plasma cells
- Positron emission tomography (PET) scanning
Treatment of SBP
Radiotherapy
It is recommended that SBP is treated with radical radiotherapy, encompassing the tumour volume shown on magnetic resonance imaging (MRI) with a margin of at least 2 cm and treating to a dose of 40 Gy in 20 fractions (grade B recommendation, based on level III evidence).
For SBP >5 cm, a higher dose of up to 50 Gy in 25 fractions should be considered (grade C recommendation, based on level IV evidence).
Patients with SBP require careful monitoring to detect progression to MM, possibly 6 weekly for 6 months with extension of clinic appointments thereafter. Assessment of signs and symptoms should be undertaken in conjunction with laboratory investigations (haematology, biochemistry, serum and urine paraprotein estimation) (grade C recommendation, based on level IV evidence).
Patients not responding to radiotherapy (see above) should be treated with chemotherapy. A suggested approach is to follow guidelines for the treatment of MM. In younger patients, this would include high dose therapy and autologous haemopoietic stem cell transplantation (grade C recommendation, based on level IV evidence).
Patients presenting as SBP but found on MRI to have disease at other sites should be considered as having MM and treated accordingly (grade B recommendation, based on level II evidence).
Surgery
Radiotherapy remains the treatment of choice for SBP and surgery is contra-indicated in the absence of structural compromise or neurological compromise (grade C recommendation, based on level IV evidence).
Where surgery is required, radiotherapy should also be given and the timing of surgery relative to radiotherapy should be determined for each patient (grade C recommendation, based on level IV evidence).
In cases of spinal plasmacytoma, referral for an opinion from an orthopaedic surgeon or neurosurgeon specializing in spinal surgery is advised (grade C recommendation, based on level IV evidence).
Reconstruction of the anterior column may be beneficial (grade C recommendation, based on level IV evidence).
Adjuvant Chemotherapy
There are insufficient data to recommend adjuvant chemotherapy in SBP.
It may be appropriate to consider adjuvant chemotherapy in patients at higher risk of treatment failure (e.g. those with bulky disease [>5 cm]) (grade C recommendation, based on level IV evidence).
Solitary Extramedullary Plasmacytoma (SEP)
Diagnosis and Investigation of SEP
Diagnostic criteria
CT or MRI scanning is required to delineate the extent of the lesion but the role of MRI scanning of other areas in the staging of SEP has not been evaluated. As there is a low risk of progression to MM in these patients and the role of MRI in the staging of SEP has not been studied, we do not consider MRI of the spine to be necessary for the diagnosis of SEP. Recommended diagnostic criteria are shown in table below, titled "Recommended diagnostic criteria for solitary bone plasmacytoma (SBP) and extramedullary plasmacytoma (SEP)."
Pathology review
For most patients the diagnosis can be established by fine needle aspiration or biopsy. As these tumours are rare, and can be confused with non-Hodgkin's lymphoma, pathology review by a histopathologist with a special interest in lymphoproliferative disorders is strongly recommended.
Investigations
As noted above, CT or MRI scanning is required to delineate the extent of the lesion but we do not consider MRI of other areas (see above) to be necessary. Other investigations should be as for SBP (see above).
Treatment of SEP
Radiotherapy
Solitary extramedullary plasmacytoma should be treated by radical radiotherapy encompassing the primary tumour with a margin of at least 2 cm (grade B recommendation, based on level III evidence).
The cervical nodes should be included if involved. The first echelon cervical nodes should be included in SEP of Waldeyer's ring (grade B recommendation, based on level III evidence).
For SEP up to 5 cm a radiotherapy dose of 40 Gy in 20 fractions is recommended.
For bulky SEP of >5 cm, a higher dose of up to 50 Gy in 25 fractions is recommended (grade B recommendation, based on level III evidence).
Surgery
Radiotherapy alone is the treatment of choice for head and neck SEP (grade B recommendation, based on level III evidence).
Radical surgery should be avoided in head and neck SEP (grade C recommendation, based on level IV evidence).
For SEP at other sites complete surgical removal should be considered if feasible (grade B recommendation, based on level III evidence).
Patients with involved surgical margins should receive adjuvant radiotherapy (grade C recommendation, based on level IV evidence).
No recommendation for adjuvant radiotherapy can be made for patients who have undergone complete surgical excision with negative margins.
Adjuvant chemotherapy
Adjuvant chemotherapy should be considered in patients with tumours >5 cm and those with high grade tumours (grade C recommendation, based on level IV evidence).
Chemotherapy is indicated for patients with refractory and/or relapsed disease. Therapy as for MM is indicated (grade C recommendation, based on level IV evidence).
Patient information and support
Provision of appropriate patient information and support forms an important part of the care of patients with SBP and SEP. General principles are the same as those for patients with myeloma. The International Myeloma Foundation (UK) produces a booklet for patients with solitary plasmacytoma.
Table. Recommended Diagnostic Criteria for Solitary Bone Plasmacytoma (SBP) and Extramedullary Plasmacytoma (SEP)
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Solitary bone plasmacytoma
Single area of bone destruction due to clonal plasma cells
Histologically normal marrow aspirate and trephine
Normal results on skeletal survey, including radiology of long bones
No anaemia, hypercalcaemia or renal impairment due to plasma cell dyscrasia
Absent or low serum or urinary level of monoclonal immunoglobulin
No additional lesions on MRI scan of the spine
Solitary extramedullary plasmacytoma
Single extramedullary mass of clonal plasma cells
Histologically normal marrow aspirate and trephine
Normal results on skeletal survey, including radiology of long bones
No anaemia, hypercalcaemia or renal impairment due to plasma cell dyscrasia
Absent or low serum or urinary level of monoclonal immunoglobulin
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Definitions:
Levels of Evidence
Ia Evidence obtained from meta-analysis of randomised controlled trials
Ib Evidence obtained from at least one randomised controlled trial
IIa Evidence obtained from at least one well-designed, non-randomised study, including phase II trials and case + control studies
IIb Evidence obtained from at least one other type of well-designed, quasi-experimental study (i.e. studies without planned intervention, including observational studies)
III Evidence obtained from well-designed, non-experimental descriptive studies. Evidence obtained from meta-analysis or randomised controlled trials or phase II studies which is published only in abstract form
IV Evidence obtained from expert committee reports or opinions and/or clinical experience of respected authorities
Grades of Recommendations
Grade A, evidence level Ia, Ib
Recommendation based on at least one randomised controlled trial of good quality and consistency addressing specific recommendation
Grade B, evidence level IIa, IIb, III
Recommendation based on well-conducted studies but no randomised controlled trials on the topic of recommendation
Grade C, evidence level IV
Evidence from expert committee reports and/or clinical experiences of respected authorities
