Short course prophylactic cranial irradiation for small cell lung cancer

Ultrarapid high-dose course of prophylactic cranial irradiation in small-cell lung cancer: evaluation of late neurologic morbidity in 16 long-term survivors

Despite the reduction in the incidence of brain metastases following prophylactic cranial irradiation (PCI) in patients with small-cell lung cancer (SCLC), the use of this modality is still controversial due to the lack of improvement in survival and the appearance of neurotoxicity in long-term survivors. Moreover, the optimum dose, fraction size, and timing are not known. From 1980 to 1988, 70 patients with limited stage SCLC underwent PCI after or during multimodality treatment of their primary tumor. Most of these patients (75.7%) received an unconventional ultrarapid high-dose course of 17 Gy in two fractions over 3 days. Long-term (range 60-138 months) survivors (n = 16) were invited to have a complete neurological evaluation including computed cranial tomography (CCT), 99mTc-HMPAO single photon emission computerized tomography (SPECT) scan, electroencephalography (EEG), magnetic resonance imaging (MRI), and neuropsychometry. Delayed neurologic complications or psychometric impairment was observed in 46% of patients. One or more abnormalities were detected by CCT in all patients, and the presence of neurologic complications seemed to correlate with periventricular and subcortical white matter changes. A strong correlation was found between CCT and SPECT periventricular white matter changes. Although the incidence of late neurologic toxicity following this rapid course of irradiation was high, clinical findings were less severe than expected, and all the patients were capable of self-care.

Should current management of small cell lung cancer include prophylactic cranial irradiation?

The literature on the use of prophylactic cranial irradiation (PCI) in the management of small cell lung cancer (SCLC) is reviewed, focusing on the ten randomized trials published until 1991. Eight out of ten randomized trials have shown some reduction in the frequency of CNS relapse in patients who have had PCI, whereas none have shown any survival benefit associated with PCI. Current data indicate that survival is exclusively dependent on an effect of PCI in only a very limited subgroup of patients (10% of complete responders). It is generally agreed that PCI is not justified in patients who are not in CR, but even in this situation it is unknown whether PCI is necessary. The current therapeutic potentials seem to leave comparable fractions of patients without sufficient palliation of their symptomatic brain metastases regardless of whether or not PCI is given. Data from sufficiently large randomized trials have to be matured and analyzed, before the role of PCI in SCLC can be defined.

The role of prophylactic brain irradiation in limited stage small cell lung cancer: clinical, neuropsychologic, and CT sequelae

Ninety-four patients with limited stage small cell lung cancer treated between 1981 and 1985 with a regimen including prophylactic brain irradiation (PBI) after combination chemotherapy were assessed for compliance with PBI, brain relapse, and neurologic morbidity. Seventy-seven percent of patients had PBI and of these, 22% developed brain metastases after a median time of 11 months post treatment. The brain was the apparent unique initial site of relapse in 10% of PBI cases but more commonly brain relapse was preceded or accompanied by failure at other sites, especially the chest. Brain metastases were the greatest cause of morbidity in 50% of PBI failures. Twelve of 14 PBI patients alive 2 years after treatment had oncologic, neurologic, and neuropsychological evaluation, and brain CT. All long-term survivors were capable of self care and none fulfilled diagnostic criteria for dementia, with three borderline cases. One third had pretreatment neurologic dysfunction and two thirds post treatment neurologic symptoms, most commonly recent memory loss. Fifty percent had subtle motor findings. Intellectual functioning was at the 38th percentile with most patients having an unskilled occupational history. Neuropsychologic impairment ratings were borderline in three cases and definitely impaired in seven cases. CT scans showed brain atrophy in all cases with mild progression in those having a pre-treatment baseline. Periventricular and subcortical low density lesions identical to the CT appearance of subcortical arteriosclerotic encephalopathy were seen in 82% of posttreatment CT studies, and lacunar infarcts in 54%. Neuropsychologic impairment scores and the extent of CT periventricular low density lesions were strongly associated (rank correlation 0.7, p less than .05). Overall, PBI after intensive combination chemotherapy did not induce gross dementia or neurologic dysfunction but its risk/benefit ratio is not overwhelmingly favorable, with failure to prevent brain relapse in 1/5 patients and subtle but detectable motor findings and neuropsychologic impairment in the majority.