Accuracy of GFR estimation by the Cockroft and Gault, MDRD, and Wright equations in Oncology patients with renal impairment.

Estimation of renal function is crucial to guidance of systemic chemotherapy. With stable creatinine levels, the glomerular filtration rate (GFR) is often estimated from a single measurement of serum creatinine. We compared accuracy of the Cockroft and Gault (C&G), modifying diet in renal diseases (MDRD) and Wright estimates in Oncology patients with renal impairment. Analysis was carried out on the basis of monodentate platinum treatment as the nephrotoxic mechanism of these drugs may affect accuracy of these estimates. Sixty-two consecutive patients with stable creatinine levels who had isotopic GFR measurement of ≤ 60 ml min(-1) at a regional cancer center were reviewed. Twenty-nine were on monodentate platinum treatment. Isotopic GFR was compared with estimated GFR by the three equations. We defined three categories of estimate based on the fractional difference from isotopic GFR: 'perfect' (< 10%), 'reasonable' (≥ 10% but < 30%) and 'poor' (≥ 30%). There was a trend toward provision of more perfect estimates by the MDRD equation particularly in patients on monodentate platinum treatment. Similar numbers had poor estimates from either of these equations, particularly at extremes of body weight. The MDRD formula may be the most accurate of these equations in Oncology patients with renal impairment, particularly with monodentate platinum treatment.

Breast radiotherapy for occult breast cancer with axillary nodal metastases--does it reduce the local recurrence rate and increase overall survival?

AIMS: The optimal management of axillary lymph node metastases from occult breast cancer (TXN1-2M0) is uncertain and practice varies in the use of primary breast radiotherapy. We conducted a retrospective review to examine clinical outcomes for patients managed with or without primary breast radiotherapy. MATERIALS AND METHODS: Case records from the clinical oncology database were reviewed to identify patients presenting with axillary nodal metastases but no detectable primary tumour between 1974 and 2003. Fifty-three patients with TXN1-2M0 breast cancer were identified, representing 0.4% of patients managed for breast cancer during this period. Of those tested, 59% had oestrogen receptor-positive tumours. Seventy-seven per cent received ipsilateral breast radiotherapy. RESULTS: There was a trend towards reduced ipsilateral breast tumour recurrence in patients who received radiotherapy (16% at 5 years, 23% at 10 years) compared with those who did not (36% at 5 years, 52% at 10 years). Similarly, the locoregional recurrence rate was 28% at 5 years for patients who received radiotherapy compared with 53.7% at 5 years for non-irradiated patients. Breast cancer-specific survival was higher (P=0.0073; Log-rank test) in patients who received ipsilateral breast radiotherapy (72% at 5 years, 66% at 10 years) compared with those who did not (58% at 5 years, 15% at 10 years). CONCLUSION: Primary breast radiotherapy may reduce ipsilateral breast tumour recurrence and may increase survival in patients presenting with axillary lymph node metastases and occult breast primary (TXN1-2M0). Larger studies or prospective registration studies are needed to validate these findings.