Chronic lymphocytic leukemia / small lymphocytic lymphoma

CLL predominantly involves blood and marrow; SLL predominantly involves lymph nodes or other tissue with a lower circulating clonal B-cell burden. Diagnosis uses the characteristic mature B-cell phenotype in the right clinical setting. SLL usually requires tissue assessment, while typical CLL can often be diagnosed from blood flow cytometry.

Monoclonal B-cell lymphocytosis (MBL) is a related finding that does not meet CLL/SLL criteria and has its own monitoring needs. Other CD5-positive B-cell disorders, particularly mantle cell lymphoma, must be excluded when findings are atypical. CLL/SLL is also distinct from Waldenström macroglobulinemia.

Treatment is considered for clinically active disease: progressive marrow failure from CLL, substantial or symptomatic nodes/spleen, significant disease-related symptoms, rapidly progressive lymphocytosis or certain autoimmune complications not adequately controlled by other treatment. Infection and other causes must be excluded before attributing fever, weight loss or falling counts to CLL.

An unfavorable marker or an elevated lymphocyte count alone does not automatically require treatment. The randomized CLL12 study did not demonstrate an overall-survival advantage from early ibrutinib in its asymptomatic population. Structured observation includes examinations, blood counts, infection prevention and clear symptoms that should prompt earlier review.

Rai or Binet stage describes clinical disease features; CLL-IPI estimates risk in an appropriate setting. Neither replaces treatment indications. Before treatment, assess del(17p) by cytogenetic testing and TP53 mutations by sequencing, as either can affect drug selection. Reassessment before later treatment lines matters because the disease can evolve.

IGHV mutation status is a separate, usually stable characteristic assessed before first treatment. “Mutated” IGHV is not the same as a harmful inherited mutation. Kidney function, heart rhythm, blood pressure, bleeding risk, hepatitis status and all concurrent drugs also help determine a feasible plan.

Options include venetoclax–obinutuzumab and second-generation BTK-based treatment, with the choice individualized. In February 2026 the FDA approved acalabrutinib–venetoclax for adults with CLL/SLL. The supporting AMPLIFY randomized trial excluded del(17p)/TP53-mutated disease; this evidence boundary should be discussed when considering a high-risk patient, even though the US indication is broader.

Fixed duration is a planned regimen, not simply stopping a continuous drug once the blood count looks normal. Conversely, a continuous approach may be reasonable when visits or venetoclax ramp-up are difficult. The discussion should include expected monitoring, daily treatment burden and what happens at relapse.

Venetoclax initiation requires tumor-lysis risk assessment based on disease burden and kidney function, with staged dosing and appropriate blood tests, hydration and monitoring. Some patients need inpatient monitoring. BTK inhibitors require attention to bleeding, rhythm problems, blood pressure, infections and interactions; do not stop or restart them independently around procedures.

An early increase in blood lymphocytes with a BTK inhibitor can reflect redistribution rather than failure if other findings improve. MRD can describe response depth after some fixed-duration regimens, but it is not a universal instruction to stop, prolong or change every treatment outside the applicable protocol.

If a covalent BTK inhibitor is stopped for intolerance, another agent may sometimes be used, depending on the toxicity. Progression while taking it raises a different resistance problem; simply substituting another covalent BTK inhibitor may not solve it. After venetoclax-based therapy, the interval off treatment, earlier tolerance and prior BTK exposure help guide retreatment or a change of class.

Current US pirtobrutinib labeling covers relapsed/refractory adult CLL/SLL after a covalent BTK inhibitor; it no longer requires the older restriction of prior exposure to both BTK and BCL2 inhibitors. The practical sequence still depends on prior response and available alternatives. Avoid a treatment gap that could cause disease flare while arranging the next line.

China has additional BCL2 options. The manufacturer's approval notice specifies lisaftoclax for adults previously treated with at least one systemic therapy including a BTK inhibitor; sonrotoclax has also received Chinese approval for relapsed/refractory CLL/SLL. Exact local labeling and access must be checked, and these approvals do not establish superiority to venetoclax or universal activity after BCL2 resistance.

Lisocabtagene maraleucel has a US accelerated-approval indication for adults with relapsed/refractory CLL/SLL after at least two prior lines including a BTK and a BCL2 inhibitor. CAR-T requires assessment of fitness, manufacturing and bridging needs, infection risk and immune toxicities. Trials and, for selected patients, allogeneic transplantation remain relevant after multiple resistance mechanisms.

Rapidly enlarging nodes, a new dominant mass, worsening systemic symptoms or a disproportionate LDH rise can raise concern for Richter transformation into an aggressive lymphoma. Infection and other causes remain possible. PET/CT can help choose a biopsy site, but uptake alone does not establish transformation.

Tissue diagnosis distinguishes transformation from progressive or accelerated CLL. The lymphoma subtype and whether it is clonally related to the CLL affect treatment planning. A transformed lymphoma should not simply be managed as another routine CLL relapse; a specialist lymphoma review and trial discussion are important.

CLL itself can impair immunity even before treatment. Vaccination planning, prompt infection assessment, hepatitis screening before relevant antibodies and regimen-specific prophylaxis matter. Immunoglobulin replacement is considered for selected patients with recurrent serious infections and low immunoglobulins, not automatically for every low result.

Autoimmune hemolytic anemia or immune thrombocytopenia may need a different first response from marrow failure caused by leukemia. Maintain age-appropriate cancer screening and skin protection. For a review, bring treatment start/stop dates and reasons, FISH/TP53/IGHV reports, kidney and cardiac records, infection history and any suspected-transformation biopsy.