What should be monitored in a patient with a history of colon cancer on their second cycle of FOLFOX (oxaliplatin, leucovorin, 5-fluorouracil) chemotherapy?

Monitoring Parameters for Colon Cancer Patients on Second Cycle of FOLFOX Chemotherapy

For a patient with colon cancer receiving their second cycle of FOLFOX chemotherapy, you must monitor complete blood counts, liver function tests, renal function, electrolytes (particularly potassium, magnesium, and calcium), and assess for peripheral neuropathy before each cycle. 1, 2

Hematologic Monitoring

Complete Blood Count (CBC) is mandatory before each cycle:

• Monitor for grade 3-4 neutropenia, which occurs in 41-44% of patients receiving FOLFOX 2
• Check for thrombocytopenia (grade 3-4 occurs in 2-5% of patients) 2
• Delay treatment if neutrophils <1.5 × 10⁹/L or platelets <75 × 10⁹/L 2
• Watch for signs of sepsis, neutropenic sepsis, or septic shock, which can be fatal 2

Neurologic Assessment

Peripheral neuropathy evaluation is critical at every visit:

• Acute neuropathy occurs in approximately 30% of patients in any individual cycle and affects 56% overall 2
• Specifically assess for pharyngolaryngeal dysesthesia (1-2% incidence), which presents as subjective dysphagia or dyspnea 2
• Warn patients to avoid cold exposure - do not use ice for mucositis prophylaxis as cold temperature exacerbates acute neurological symptoms 2
• Grade neuropathy using NCI CTC criteria: grade 1 (mild paresthesias), grade 2 (moderate sensory loss), grade 3 (severe sensory loss interfering with function) 2
• Delayed neuropathy (persistent >14 days) occurred in 48% of patients and can interfere with daily activities like writing, buttoning, and walking 2

Hepatic Function Monitoring

Liver function tests must be checked before each cycle:

• Increased transaminases occur in 57% of patients on FOLFOX versus 34% on fluorouracil/leucovorin alone 2
• Elevated alkaline phosphatase occurs in 42% versus 20% 2
• Monitor for hepatic vascular disorders including peliosis, nodular regenerative hyperplasia, perisinusoidal fibrosis, and veno-occlusive lesions 2
• Evaluate for unexplained portal hypertension not attributable to liver metastases 2

Electrolyte Monitoring

Electrolyte abnormalities require close surveillance:

• Severe hypokalaemia is a significant risk - can drop to levels as low as 1.4 mmol/L 3
• Monitor potassium, magnesium, and calcium levels before each cycle 2, 3
• Hypokalaemia results from chemotherapy-induced diarrhea, vomiting, and intracellular shift from oxaliplatin (administered in 5% dextrose) 3
• Correct electrolyte abnormalities prior to each treatment and provide supplementation as needed 2, 3

Cardiac Monitoring

ECG monitoring is necessary in high-risk patients:

• QT prolongation and ventricular arrhythmias, including fatal torsade de pointes, have been reported 2
• Monitor ECG in patients with congestive heart failure, bradyarrhythmias, electrolyte abnormalities, or those taking QT-prolonging drugs 2
• Correct electrolyte abnormalities before initiating each cycle 2

Pulmonary Assessment

Evaluate for respiratory symptoms at each visit:

• Ask about non-productive cough, dyspnea, or crackles 2
• Combined incidence of cough and dyspnea is 7.4% in adjuvant treatment 2
• Pulmonary fibrosis occurs in <1% but can be fatal 2
• Withhold oxaliplatin for unexplained respiratory symptoms until pulmonary investigation excludes interstitial lung disease 2

Renal Function

Monitor creatinine and creatinine clearance:

• Assess renal function before each cycle as part of standard monitoring 1
• Important for dose adjustments and managing electrolyte abnormalities 3

Clinical Assessment

Perform focused physical examination:

• Assess performance status and ability to tolerate treatment 1
• Check for signs of infection, particularly with neutropenia 2
• Evaluate gastrointestinal symptoms: nausea (8% grade 3/4), diarrhea (9-11% grade 3/4) 4, 5
• Monitor for signs of rhabdomyolysis (rare but can be fatal) 2

Tumor Response Evaluation

Imaging is not required at cycle 2, but plan for assessment:

• Response evaluation should occur after 2-3 months of treatment using CT scan with contrast 6
• Monitor CEA levels if initially elevated 1, 6

Treatment Modifications

Be prepared to adjust dosing based on toxicities:

• Dose reduce oxaliplatin after recovery from grade 4 neutropenia, febrile neutropenia, or grade 3-4 thrombocytopenia 2
• Consider discontinuing oxaliplatin after 3-4 months if significant neurotoxicity develops (≥grade 2) while maintaining fluoropyrimidine 1
• Permanently discontinue for PRES, confirmed interstitial lung disease, pulmonary fibrosis, or rhabdomyolysis 2