Citations

Particle detection instrumentation to address the in vivo verifications of proton dose and range is under development as part of a proton therapy research program focused on patient quality assurance. For in vivo proton range verification, a collimated gamma detector array is under construction to indirectly measure the position of the Bragg peak for each proton beam spot to within 1–2 mm precision. For dose flux verification, a proton fluence detector based on the technology of the Micromegas is under construction. This detector has an active area of about 100 cm2, coordinate resolution of better than 1 mm, and handling of incident proton beam fluxes of 109–1013 particles/s.

Recent literature has demonstrated concern over the risk of Pneumocystis jirovecii pneumonia (PJP) when administering rituximab with combination chemotherapy such as in R‐CHOP; however, the exact risk and potential need for prophylaxis is unknown. We sought to determine the incidence of PJP infection following R‐CHOP administration in patients with B‐cell lymphoma. Consecutive patients diagnosed with B‐cell lymphoma receiving R‐CHOP were evaluated from chemotherapy initiation until 180 days after the last administration. The primary outcome was cumulative incidence of PJP infection. Secondary endpoints included the association of rituximab, prednisone and subsequent chemotherapy with PJP infection risk. A total of 689 patients (53% male, median age 66 years) were included. Seventy‐three percent of patients completed at least 6 cycles of R‐CHOP treatment. Median rituximab and prednisone cumulative doses were 3950 mg and 5325 mg, respectively. Median daily prednisone dose through end of treatment was 45 mg (range 7.6 mg to 119 mg). The cumulative incidence of PJP was 1.51% (95% CI 0.57–2.43, at maximum follow‐up of 330 days), below 3.5%, the conventional threshold for prophylaxis. Univariate analysis did not detect a statistically significant association between PJP and rituximab, steroids, or receipt of additional chemotherapy in this patient population. Our results demonstrate a low occurrence of Pneumocystis pneumonia during R‐CHOP treatment of B‐cell lymphoma and argue against universal anti‐Pneumocystis prophylaxis in this setting. Further investigations should focus on targeted anti‐Pneumocystis prophylaxis for patients presenting with high‐risk baseline characteristics or when receiving rituximab‐inclusive intensive combination chemotherapy regimens as treatment for other aggressive lymphoma subtypes. Am. J. Hematol. 91:1113–1117, 2016. © 2016 Wiley Periodicals, Inc.

Bone marrow is a complex organ responsible for the regulation of hematopoietic cell distribution throughout the human body. Patients receiving antineoplastic agents as a therapeutic intervention for hematologic malignancy often experience varying degrees of myelotoxicity. Antineoplastic agents cause hypocellularity in marrow resulting in a reduction in hematopoietic tissue activity and a corresponding decline in cell production. Quantifying the adverse effects on hematopoiesis is based on the properties of a single agent, the use of individual drugs within a combination chemotherapy regimen, and the course, or courses, of chemotherapy designed to treat cancer. The direct or indirect suppression of erythrocytes, granulocytes, and megakaryocytes has potential for multiple negative clinical consequences ranging from increased monitoring of blood counts to life-threatening infection and death. This review will provide an overview of the structure and function of competent adult bone marrow, describe the process of hematopoiesis, and characterize the myelotoxicities associated with common antineoplastic agents currently used in the treatment of cancer.