Long-term evolution of renal function in patients with ovarian cancer after whole abdominal irradiation with or without preceding cisplatin

Basal renal function reserve and mean kidney dose predict future radiation-induced kidney injury in stomach cancer patients

BACKGROUND

Adjuvant chemoradiotherapy (CRT) improves the survival in patients with locally advanced stomach cancer. The kidneys are the major dose-limiting organs for radiotherapy (RT) in upper abdominal cancers. We aimed to evaluate the impact of adjuvant CRT on renal function of patients with stomach cancer.

MATERIAL AND METHODS

Fifty-nine stomach cancer patients who underwent postoperative CRT were included. Demographic parameters (age, gender), and basal and 12th-month biochemical parameters were recorded. Mean kidney dose (MKD) administered was determined. Estimated glomerular filtration rate (eGFR) was calculated by modification of diet in renal disease formula.

RESULTS

Fifty-nine patients were recruited (age 60.8 ± 11.9 years; female/male 25/34; follow-up duration 15.6 ± 9.8 months). Twenty-one patients (35.6 %) had basal eGFR <90 ml/min/1.73 m(2). When the basal and 12th-month eGFR was compared, eGFR decreased in 27 patients (45.8 %), whereas eGFR remained stable in 32 (54.2 %) patients. Cox regression analyses revealed that a MKD ≥1,500 cGy and basal eGFR <90 ml/min/1.73 m(2) significantly increased the risk of a decreased eGFR at 12th month (HR = 2.288, 95 % CI 1.009-5.188, p = 0.048 and HR = 2.854, 95 % CI 1.121-7.262, p = 0.028, respectively).

CONCLUSION

MKD ≥1,500 cGy and a basal eGFR <90 ml/min/1.73 m(2) significantly increased the risk of a decreased eGFR at 12th month. We suggest that patients with stomach cancer be evaluated for their basal renal reserve prior to RT, and it may be more convenient to further minimize the dose to the kidneys with more sophisticated RT techniques in patients with stomach cancer, more specifically in patients with decreased renal reserve.

Impact of renal function on treatment options and outcomes in advanced non-small cell lung cancer

INTRODUCTION

Certain chemotherapeutic agents commonly used for advanced non-small cell lung cancer (NSCLC) require minimum threshold renal function for administration. To determine how such requirements affect treatment options, we evaluated renal function patterns in this population.

METHODS

We performed a single-center retrospective analysis of patients treated for stage IV NSCLC from 2000 to 2007. Associations between patient characteristics, calculated creatinine clearance (CrCl), and clinical outcomes were determined using univariate and multivariate analyses, Cox proportional hazard models, and mixed model analysis.

RESULTS

298 patients (3930 creatinine measurements) were included in the analysis. Patients had a median of 5 (interquartile range [IQR] 4-18) Cr measurements. Median baseline CrCl was 96 mL/min (IQR 74-123 mL/min); median nadir CrCl was 78 mL/min (IQR 56-100mL/min). Renal function was associated with age (P<0.001), race (P=0.009), and gender (P=0.001). 23% of patients had a recorded CrCl<60 mL/min (threshold for cisplatin), with median onset 83 days after diagnosis and median time to recover to ≥60 mL/min of 27 (IQR 3-85) days; 11% of patients had a recorded CrCl<45 mL/min (threshold for pemetrexed), with median onset 122 days after diagnosis and median recovery time of 36 (IQR 3-73) days. For both thresholds, approximately 35% of patients had no documented recovery.

CONCLUSIONS

In this cohort of patients treated for stage IV NSCLC, renal function falls below commonly used thresholds for cisplatin and for pemetrexed in fewer than a quarter of patients. However, these declines may preclude administration of these drugs for prolonged periods.

Radiation-associated kidney injury

The kidneys are the dose-limiting organs for radiotherapy to upper abdominal cancers and during total body irradiation. The incidence of radiotherapy-associated kidney injury is likely underreported owing to its long latency and because the toxicity is often attributed to more common causes of kidney injury. The pathophysiology of radiation injury is poorly understood. Its presentation can be acute and irreversible or subtle, with a gradual progressive dysfunction over years. A variety of dose and volume parameters have been associated with renal toxicity and are reviewed to provide treatment guidelines. The available predictive models are suboptimal and require validation. Mitigation of radiation nephropathy with angiotensin-converting enzyme inhibitors and other compounds has been shown in animal models and, more recently, in patients.

IMRT of large fields: whole-abdomen irradiation

PURPOSE

To assess the feasibility of inverse planning for whole-abdomen intensity-modulated radiation therapy (IMRT) with bone marrow and kidney sparing and to develop approaches to circumventing field size restrictions in the application of whole-abdomen IMRT using dynamic multileaf collimators (DMLC).

METHODS AND MATERIALS

The entire peritoneal cavity as derived from serial computerized tomography scans was defined as the gross target volume, whereas the planning target volume (PTV) was defined as the gross target volume plus a 5-mm margin extending 1 cm superiorly and inferiorly. In 10 randomly selected patients, the PTV ranged from 5629 to 12578 cc (median 7935 cc), and the superior-inferior, lateral, and anterior-posterior dimensions of the PTV ranged from 37 to 46 cm (median 42.5 cm), 27 to 33 cm (median 29 cm), and 18 to 23 cm (median 20 cm), respectively. A single isocenter was defined for patients with field length <40 cm. For patients with fields >40 cm, two isocenters were defined: one in the abdominal region, and the other in the pelvis. For IMRT planning, five 15-MV intensity-modulated beams at gantry angles of 180 degrees, 105 degrees, 35 degrees, 325 degrees, and 255 degrees were used. Optimization was designed to spare kidneys and bones. To fully account for the significant scattered dose contributions, an iterative process for dose calculations was implemented in the optimization. To overcome the 15-cm field width limit of our DMLC delivery system, fields with a width >15 cm were split into two or more subfields. To minimize field match errors, adjacent subfields overlapped by at least 2 cm, with intensity "feathering" in the overlap region. For patients with two isocenters, fields were overlapped and feathered in the cephalad-caudad direction by at least 3 cm. For comparison, conventional anterior-posterior/posterior-anterior 6-MV photon beams with posterior kidney blocks at extended distance were also generated for each patient.

RESULTS

Treatment plan optimization calculations required 20-80 min on a 500-MHz DEC alpha workstation. Including beam splitting, an average of 16 DMLC beams was used per patient. Delivery of 150 cGy required, on average, 1442 monitor units. For the same dose constraints on the kidneys, whole-abdomen IMRT resulted in significant dose reduction to the bones and improved PTV coverage as compared to conventional treatment. For a prescription dose of 30 Gy, the volume of the pelvic bones receiving more than 21 Gy was reduced on average by almost 60% with IMRT, and the mean dose to all bones was reduced from 24.0 +/- 1.5 Gy to 18.5 +/- 1.0 Gy (p = 0.002). PTV coverage, as measured by V95 (the volume receiving 95% of the prescription dose), improved from 71.7 +/- 4.8% with conventional treatment to 83.5 +/- 3.9% with IMRT (p = 0.002), although small regions of underdose in areas near the kidneys could not be avoided completely. The high-dose regions within the PTV, as measured by D05 (the dose covering 5% of PTV volume), increased slightly from 31.2 +/- 0.6 Gy with conventional treatment to 32.8 +/- 0.2 Gy with IMRT.

CONCLUSION

We have developed a process to plan and deliver whole-abdomen IMRT using standard linear accelerators and DMLC. IMRT can achieve better PTV coverage with the same level of kidney sparing and improved sparing of the bone marrow. These methods may be applicable also to other sites requiring large-field irradiation.

Long-term renal function after treatment for malignant germ-cell tumours

OBJECTIVE

To evaluate prospectively renal function in patients with malignant germ-cell tumours (MGCTs) >10 years after retroperitoneal lymph node dissection alone (RPLND), radiotherapy alone (RAD) or different schedules of cisplatin-based chemotherapy with or without surgery/radiotherapy (CHEM).

PATIENTS AND METHODS

In 85 patients, three groups were identified: RPLND, 14; RAD, 18; CHEM, 53, with subdivision of the latter group according to the cumulative cisplatin dose or the additional use of radiotherapy. Renal function was determined by 131Iodine Hippuran clearance or 99m DTPA glomerular filtration rate, and was assessed before treatment and four times during 14 years of follow-up. A value of <70% of the upper limit of the normal range identified impaired renal function.

RESULTS

Twenty-five patients displayed long-term impaired renal function, 23 of them from the RAD or CHEM group. In the RAD group, renal function decreased by 8%, whereas a 14% reduction of renal function was observed in the CHEM group. In the CHEM group the cumulative dose of cisplatin, and in the RAD group the age at treatment, were associated with impairment of renal function. Combining all patients, age at treatment and the type of treatment were associated with impaired renal function.

CONCLUSIONS

In 20-30% of the patients with germ-cell tumour, standard radiotherapy and chemotherapy strategies are followed by long-term subclinical impaired renal function. These findings support current intentions to avoid overtreatment with these treatment modalities.