Medicines

Why eviQ dosing adjustment protocols were disregarded in practice


eviQ chemo dose adjustment protocols for haematological toxicity have been revised to allow more aggressive therapy following a survey that found most medical oncologists were ignoring them for being too conservative for real world use.

A new paper explains how protocols were updated recently to reflect clinical practice in which oncologists are prepared to keep using antineoplastic chemotherapy in curative settings even if the eviQ advised neutrophil and platelet thresholds were exceeded.

Writing in the Internal Medical Journal, Dr Wanyuan Cui and colleagues say the original haematological thresholds for delaying treatment were perceived as too conservative and inflexible for real world setting where patients may differ in age and co-morbidities from those in clinical trials or there may be different patient and treatment intent.

This was confirmed in a survey that attracted responses from 153 medical oncologists, of whom two thirds (67%) said that they did not follow the eviQ haematological dose modification guidelines.

The main reasons given were overly conservative cut off levels (48%) and need to personalise modifications based on patient and treatment intent (23%).

The original recommended haematological thresholds to delay or dose reduce treatment were: neutrophil count <1.5 x 109/L and platelet count <100 x 109/L.

However, oncologists appeared less likely to delay/reduce treatment for curable cancers such as early breast cancer, where lower doses and intensities of chemotherapy have been shown to have lower disease-free survival and overall survival rates. Conversely they were more likely to follow conservative protocols in palliative treatment when quality of life was a main goal.

In the survey, medical oncologists indicated that they were more willing to delay and/or dose reduce palliative treatment at a neutrophil threshold of less than 1.5 x 109/L than curative treatment (36% and 8% respectively).

Similarly 34% of clinicians delayed and/or dose reduced curative treatment at a platelet count of less than 100 x 109/L, compared to 70% for palliative treatment.

Most clinicians indicated they would delay treatment at a neutrophil count of less than 1.0 x 109/L (97% for palliative treatment, 94% for curative treatment) and at a platelet count of less than 75 x 109/L (98% for both curative and palliative treatment).

Dr Cui said that as a result of the survey findings, eviQ updated its haematological dose modification recommendations for a broad range of medical oncology protocols from mid 2018 to reflect the actual practice.

In curative treatment protocols, the cut off for treatment delay for platelets is reduced from 100 to 75 x 109 /L with recommendation ‘Refer to local institution guidelines; it is the view of the expert clinicians that treatment should continue if the patient is clinically well.’

For palliative treatment protocols the cut off for treatment delay for neutrophils is reduced from 1.5 x 109 /L to 1.0 x 109 /L with the recommendation: ‘Refer to local institution guidelines; it is the view of the expert clinicians that treatment should continue if the patient is clinically well.’

Similarly the cut off for treatment delay for platelets is reduced from 100 to 75 x 109 /L with the recommendation: ‘The general recommendation is to delay; however if the patient is clinically well it may be appropriate to continue treatment; refer to treating team and/or local institution guidelines.

“While eviQ recommendations are a useful guide, they cannot account for individual patient, tumour and clinical factors,” Dr Cui and colleagues said.

“With advances in digital medicine and growing numbers of tumour specific registries, the potential to measure outcomes compared to treatment dose in a real-world setting may become possible in the future, and thus provide a more accurate guide for dosing of anti-neoplastic treatment,” they concluded.

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