Exercise as it relates to Disease/Long-term follow-up after cancer rehabilitation using high-intensity resistance training: persistent improvement of physical performance and quality of life

This is a critique of the research article: De Backer, I., Vreugdenhil, G., Nijziel, M. et al. Long-term follow-up after cancer rehabilitation using high-intensity resistance training: persistent improvement of physical performance and quality of life. Br J Cancer 99, 30–36 (2008).

Research Background

Many short-term studies have been completed to assess the effects of physical activity interventions in post-treatment cancer patients, however the long-term effects leave a little more to be answered. In this study, the first of its kind, the completion of an 18-week resistance training program in 68 cancer survivors was followed up for one year. There are many burdens that cancer patients and survivors face in their daily lives, including varying levels of physical and psycho social distress, possibly even extending to financial troubles. This burden can be decreased with a personalized rehabilitation program, before, during and post-treatment for most individuals and has been known in the past to include psychological, physical, financial and work-related interventions depending on the type of cancer and length of treatment.

With 69% of Australian cancer survivors expected to live for at least 5 years post-treatment as of 2015, long-term outcomes of rehabilitation programs are becoming increasingly more important as they are now needed more than ever.

Research

This is a clinical trial, assessing the long-term effects of progressive, high intensity resistance training in cancer patients as a form of rehabilitation post-treatment. As it is the first long term study of its kind for this specific cohort it seems a great addition to similar studies on cancer patients. A systematic review completed by Cheema et al found 3 out of 10 similar short-term trials included a long-term follow up post intervention which was presented as either a home-based gym program or different questionnaires. The findings of the short-term studies aligned positively with the results found in this study, showing that resistance training has the potential to reduce the side effects of cancer including fatigue and muscle wastage.

This study took post-treatment cancer patients from 2 hospitals and implemented a high intensity resistance training intervention in hospital one, and used a similar cohort in hospital two as a control group. The control hospital was unaware of the benefits of resistance training for rehabilitation in cancer patients in the intervention group. The intervention group completed an 18-week training program that started at least 6 weeks post-treatment. The program included high intensity resistance training and interval training on a cycle ergometer. Patients were trained 2x/wk for the first 12 weeks and 1x/wk for weeks 12-18 and follow up appointments were scheduled for weeks 22, 26, 30, 34 and 68.

Strength training

Wks 1-12

• 2 x 10 @ 65-80% predicted 1RM

Wks 12-18

• 2 x 20 @ 35-40% predicted 1RM

Assessed every 4 weeks and readjusted with change in predicted 1RM

Cardio

Wks 1-8

• 30s @65% MSEC
• 60s @30%
• Both before and after resistance exercises

Wks 9+

• 30 s @65%
• 30 s @30% of the MSEC

Fatigue

• Multidimensional Fatigue Index questionnaire

Health-related Quality of life

• European Organisation for Research and Treatment of Cancer Core Quality of Life Questionnaire C30 (EORTC QLQ-C30)

The control group completed the muscular strength and cardio respiratory assessments at week 68.

Results

The results of this research show significant differences in the initial 18 weeks between the control group and the intervention group in each assessed area.

Muscle strength

Increased after training up to 18 weeks where it then stabilised and was maintained up until the 68-week check in. Results show that the participants improved in each exercise they were given.

• vertical row (50%)
• leg press (33%)
• bench press (57%)
• pull over (100%)
• lunge (119%)
• abdominal crunch (37%)

Cardiopulmonary function

The week 1-18 training program improved all assessed markers including peak oxygen consumption, maximal workload, peak heart rate and ventilatory threshold. These improvements were maintained from week 18-68 with no significant increase.

• peak oxygen consumption (+12%)
• maximal workload (+15%)
• peak heart rate (+3%)
• ventilatory threshold (+16%).

Fatigue and quality of life

MFI showed improvements in all sections not including reduction in motivation in the intervention group. This improvement in fatigue outcome measures persisted until the 68-week follow up. It was shown that there was no significant difference between the intervention and control groups at the 68-week follow up. Similar to the MFI, the HRQOL survey also showed improvements in the intervention group in the short term however no significant differences were found at the 68-week check in.

As this study is the first to follow up a progressive resistance training program on cancer patients in the long term, I believe that the results were interpreted appropriately, outlining the findings using a statistical analysis with significance level of <0.01 (p-value: <0.01).

Conclusions

• The long term benefits of resistance training in this cohort show increases in muscle strength, HRQOL, and fatigue.
• Cardiopulmonary function was also shown to increase short-term with interval training.

Practical advice and further resources

• There is evidence of a significant benefit for including any type of physical activity into the rehabilitation procedures and further into the regular daily habits of post-treatment patients.
• Resistance training should be completed under advice of an accredited physician
• The Cancer Council
• eviQ - Cancer Treatments Online (for Health Professionals)
• Cancer Australia Statistics