Primary amyloidosis is a disease classified as a monoclonal gammopathy. It is a type of cancer in which protein fibres (amyloid substance) form deposits in tissues in sufficient quantities to cause a deterioration in the normal functioning of the affected organ.

The causes of the production of the amyloid substance and deposit in tissues are unknown, although primary amyloidosis is associated with the anomalous production of antibodies by cells derived from B lymphocytes, the plasma cells.

Primary amyloidosis is a very infrequent type of neoplasm. Its incidence in Spain is 9 new cases per million, per year. It mainly affects men of advanced age, the average age being 65.

Primary amyloidosis usually follows a chronic course with very slow evolution and patients can remain asymptomatic for years, in which case no treatment is required.

Once they do manifest themselves clinically, the main symptoms are: fatigue; weight loss; fluid retention (due to kidney damage that causes nephrotic syndrome); dyspnea (shortness of breath due to heart failure); enlarged liver (hepatomegaly); sensory disorders of the hands and feet; swollen tongue; a tendency for low blood pressure; diarrhoea and impotence, amongst others. These clinical manifestations are due to organ dysfunction due to the deposit of amyloid material.

Diagnosis for primary amyloidosis is based on finding amyloid material in the tissues. Usually a blood test is performed, as well as a biopsy of subcutaneous fat (positive in 80% of AL patients). If this biopsy proves negative a rectal or marrow biopsy is performed and, should the results continue to be negative, a biopsy of the affected organ is performed.

Additionally, although there may be no symptoms, it is necessary to evaluate the condition of each of the possibly affected organs. As part of the study, the precursor protein for the deposited fibres must be analysed in order to discount other types of amyloidosis such as, hereditary, secondary and senile amyloidosis.

It must first be determined whether the patient is a eligible (on account of age and level of organ damage) for an autologous transplant of hematopoietic progenitors. For eligible patients the level of toxicity of the procedure is acceptable and the transplant can therefore be considered as a therapeutic option for first line treatment. Unfortunately, this procedure does not produce a cure for the disease, but it does lead to remissions, occasionally prolonged ones, and an improvement in the affected organs.

In selected cases in which damage to the heart is the main limiting factor, a heart transplant may be proposed, followed shortly afterwards by a hematopoietic transplant.

Cases in which the patient is not a candidate for a transplant (due to either the slight, or the excessive damage caused) treatment is based on the administration of cycles of dexamethasone in association with melphalan or, more recently, bortezomib, lenalidomide or cyclophosphamide+thalidomide. Appropriate treatment for the visceral disorders produced, such as kidney or heart failure, is also included.

The aim of all these treatments is always to halt the evolution of the disease and improve the symptoms because, unfortunately, none of them can provide a cure.

The prognosis for patients with primary amyloidosis largely depends on the organs affected. The absence of a treatment capable of halting the deposits and reverting the substance already deposited, in addition to the usually advanced age of patients, means that the prognosis is poor.

For more quality information about primary amyloidosis you can consult the following websites:

• Plasma cell neoplasms treatment. National Cancer Institute
• Amiloidosis primaria: diagnóstico, pronóstico y tratamiento. Dr. Mª Teresa Cibeira and Dr. Joan Bladé
• Amyloidosis Foundation