Comparative immunologic analysis of radiotherapy to trhree anatomic areas

• Autores: Emma L. Verastegui Avilés, Rosa M. Martínez García, María Adela C. Poitevin Chacón, Rocío B. Morales Bárcenas, José Luis Barrera Franco
• Localización: Revista de oncología: Publicación oficial de la Federación de Sociedades Españolas de Oncología y del Instituto Nacional de Cancerología de México, ISSN 1575-3018, Vol. 5, Nº. 7, 2003, págs. 404-412
• Idioma: inglés
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• Resumen

  • Background. Hematological side effects are not generally expected due to radiotherapy involving limited radiation fields; however, usually neutrophil counts, hemoglobin and platelets are mainly consider. The impact on lymphocyte counts are usually not considered; although, the radiation therapy to some anatomic areas (the head and neck) is frequently associated with chronic intraoral infections. Xerostomia has been implicated as a cause of it, but local or systemic immune alterations are not usually considered.

    Methods. With the purpose of evaluating the impact of radiotherapy treatment to different anatomic sites on immune function, seventy patients were evaluated during and after radiotherapy; fifty cases with SCC H&N, ten with SCC of the uterine cervix (UC) and ten patients with central nervous system tumors (CNS). We analyzed lymphocyte counts and T cell subsets, proliferation capacity of T cells and their association with the presence of intracellular infections and disease free survival.

    Results. Severe lymphopenia was observed in patients with SCC UC and SCC H&N by the fifth week of treatment. Patients with CNS tumors developed mild lymphopenia. In patients with SCC H&N and UC lower counts were seen in B cells and total T lymphocyte counts including both CD4+ and CD8+ cell subsets. The patients with SCC UC recovered lymphocyte counts by the 24th month but T cell subsets longed beyond. None of the SCC H&N patients had fully recovered by 60 months of follow-up. Tumor free survival correlates with low lymphocyte counts.

    Discussion. This work highlights the vulnerability of the head and neck area to the impact of radiotherapy as a reservoir of lymphoid cells. The possibility of recovery as a consequence of peripheral clonal expansion may limit the antigen-specific recognition of relevant tumor or microbial antigens recognition and cause significant and prolonged immune alterations that may impact on long term survival.