Managing minimal residual malignant disease.

Area of Science:

• Oncology
• Cancer Biology
• Immunology

Background:

• Complete remission of acute leukemia and other tumors frequently leaves minimal residual disease (MRD) cells, which can cause relapse.
• These residual cells, even in G0 phase or with long generation times, can form new tumor masses due to cell kinetics, immune escape, or new promoting events.
• Maintenance chemotherapy has limited efficacy in improving survival, primarily increasing relapse incubation time rather than cure rates.

Purpose of the Study:

• To analyze the challenges posed by minimal residual disease (MRD) in cancer treatment.
• To evaluate the effectiveness of current and proposed strategies for managing MRD.
• To propose new approaches for eradicating residual cancer cells, particularly in solid tumors.

Main Methods:

• Review of existing chemotherapy and immunotherapy strategies for managing MRD.
• Analysis of cell kinetics and potential escape mechanisms of residual cancer cells.
• Proposal of intensive remission induction and bioimmunological manipulation strategies.

Main Results:

• Maintenance chemotherapy beyond initial treatment shows limited benefit and can contribute to drug resistance.
• Relapse cells can develop refractoriness to cytostatics through alternative pathways or tumor progression.
• Adjuvant immunotherapy shows potential but requires improved statistical methods and monitoring.

Conclusions:

• Intensive remission induction aiming for minimal residual disease cell number is crucial for 'curable' tumors with short cell generation times.
• Bioimmunological response manipulation can be effective against G0-phase cells.
• New methods are needed for managing residual disease in solid tumors with long generation times, potentially involving maintenance chemotherapy targeting slow-cycling cells.