POSTURAL INSTABILITY IN A PROSTATE CANCER PATIENT UNDERGOING RADIATION THERAPY
Trilok N. Monga; Uma Monga; M. Mazher Jaweed (Departments of Physical Medicine and Rehabilitation and Radiation Oncology; VA Medical Center; Baylor College of Medicine, Houston, Texas, USA)
Purpose: To objectively evaluate the postural instability in a prostate cancer patient undergoing radiotherapy.
Methods: A 68 year old male patient with a diagnosis of adenocarcinoma of prostate cancer started complaining of poor balance during the third week of radiotherapy (RT). He described the symptom as "feeling of being drunk". Symptoms would start about half an hour after radiotherapy and improve within 3-8 hours of post-radiation. There was no previous history of diabetes, poor balance, or stroke. Radiotherapy was completed with a total dose of 6800 cGy, 34 fractions over 50 days period. Blood pressure recordings during the period he had symptoms were normal. Pre and post RT, daily nerve conduction studies (NCS) in the lower limbs and the subject's standing posture was evaluated by measuring the mean dispersion index (MDI) on a Chattex balance platform for three days.
Results: NCS were normal for each of three pre-radiotherapy sessions. However, within 1-2 hours of post radiotherapy H reflex, and peroneal F wave responses were absent. During 1-2 hours post radiation, the MDI data revealed a significantly higher disturbance in postural equilibrium than pre- treatment values. These abnormalities became normal at 4 weeks after completion of radiotherapy.
Conclusions: Exact cause of poor balance is not clear. Possibility of altered moroneuron excitability, and neuropraxia are postulated.
A PROSPECTIVE STUDY OF FATIGUE IN PROSTATE CANCER PATIENTS UNDERGOING RADIOTHERAPY
Uma Monica, MD., A.J., Kerrigan, Ph.D., M., Jaweed, Ph.D. and T.N., Monga, MD., Veterans Affairs Medical Center and Baylor College of Medicine, Houston, Texas, USA
Objective: The objective of this prospective study was to determine the nature of fatigue in localized prostate cancer patients undergoing radiotherapy (RT).
Methods: Instruments used for psychological fatigue (PF) included: (1) Piper Fatigue Scale (PFS), (2) Beck Depression Inventory (BDI), (3) Epworth Sleepiness Scale (ESS), and (4) Functional Assessment of Cancer Therapy - Prostate (FACT-P). Neuromuscular efficiency (NME) of Tibiails Anterior (TA) muscle was carried out by sustained isometric contraction at 80% of maximum voluntary contraction (5 degrees of dorsifiexion) for 60 seconds on a Kin-Com force dynamometer. NME, a ratio between muscle force and corresponding integrated EMG was analyzed. Assessments were carried out before radiation therapy (PRT), at completion of RT (KTC), and at 4-5 weeks follow-up (RTF). Seventeen subjects (age 55-73 years) and seven subjects (age 60-76 years) completed PSF and NME evaluation respectively.
Results: PRT median scores on BDI, PFS, ESS, and FACT (P) were 4.00, 2.41, 6.0, and 130 respectively. No significant changes in these scores were noted at RTC and RTF. At RTC, there was a significant decline in NME of TA at the beginning (18.4%, p<.01) and the end (29.2%, p<.001) of sustained muscle contraction for 60 seconds. NME recovered at RTF.
Conclusion: A transient decline in NME at the completion of RT seems to be specific for neuromuscular performance alone and is independent of the psychological status of the patients.