Management of metastatic bone pain: preliminary results with single fraction (4 Gy) radiotherapy

Palliation of bone metastases: a survey of patterns of practice among Canadian radiation oncologists

BACKGROUND

Palliative radiotherapy constitutes nearly 50% of the workload in radiotherapy. Surveys on the patterns of practice in radiotherapy have been published from North America and Europe. Our objective was to determine the current pattern of practice of radiation oncologists in Canada for the palliation of bone metastases.

METHOD

A survey was sent to 300 practicing radiation oncologists in Canada. Five case scenarios were presented. The first three were patients with a single symptomatic site: breast cancer patient with pelvic metastasis, lung cancer male with metastasis to L3 and L1, respectively. The last two were breast and prostate cancer patients with multiple symptomatic bone metastases.

RESULTS

A total of 172 questionnaires were returned (57%) for a total of 860 responses. For the three cases with a single painful bone metastasis, over 98% would prescribe radiotherapy. The doses ranged from a single 8 to 30 Gy in ten fractions. Of the 172 respondents, 117 (68%) would use the same dose fractionation for all three cases, suggesting that they had a standard dose fractionation for palliative radiotherapy. The most common dose fractionation was 20 Gy in five fractions used by 84/117 (72%), and 8 Gy in one fraction by 19/117 (16%). In all five case scenarios, 81% would use a short course of radiotherapy (single 8 Gy, 17%; 20 Gy in five fractions, 64%), while 10% would prescribe 30 Gy in ten fractions. For the two cases with diffuse symptomatic bone metastases, half body irradiation (HBI) and radionuclides were recommended more frequently in prostate cancer than in breast cancer (46/172 vs. 4/172, P<0. 0001; and 93/172 vs. 10/172, P<0.0001, respectively). Strontium was the most commonly recommended radionuclide (98/103=95%). Since systemic radionuclides are not readily available in our health care system, 41/98 (42%) of radiation oncologists who would recommend strontium were not familiar with the dose. Bisphosphonates were recommended more frequently in breast cancer than in prostate cancer 13/172 (8%) vs. 1/172 (0.6%), P=0.001.

CONCLUSION

Local field external radiotherapy remains the mainstay of therapy, and the most common fractionation for bone metastases in Canada is 20 Gy in five fractions compared with 30 Gy in ten fractions in the US. Despite randomized trials showing similar results for single compared with fractionated radiotherapy, the majority of us still advocate five fractions. The frequency of employing a single fractionation has not changed since the last national survey in 1992. Nearly 70% use a standard dose fractionation to palliate localized painful metastasis by radiotherapy, independent of the site of involvement or tumor type. The pattern of practice of palliative radiotherapy for bone metastases in Canada is different to that reported previously from the US. The reasons why the results of randomized studies on bone metastases have no impact on the patterns of practice are worth exploring.

Single 4 Gy re-irradiation for painful bone metastasis following single fraction radiotherapy

PURPOSE

to investigate effectiveness of a single-fraction of 4 Gy given for re-treatment of bone metastasis after previous single-fraction radiotherapy (RT).

MATERIAL AND METHODS

Of 135 patients retreated, 109 patients were retreated because of pain relapsing after 4 Gy (group I, n = 34), 6 Gy (group II, n = 39), or 8 Gy (group III, n = 36), while 26 patients were re-irradiated after initial non-response (group I, n = 12; group II, n = 8; group III, n = 6).

RESULTS

Of the 109 patients that were re-irradiated for pain relapse, 80 (74%) patients responded (complete response (CR) = 31%; partial response PR) = 42%). Among the 26 patients that initially did not respond, there were 12 (46%) responses. Patients with previous CR were more likely to achieve CR than were patients with previous PR (P = 0.042). No such finding was observed for obtaining PR, which was achieved in 45% each of patients previously having either CR or PR (P = 0.99). Patients with previous CR had similar chance to obtain either CR or PR (P = 0.65), while previous PR influenced subsequent response in the way of achieving more PRs than CRs (P = 0.00054). Combined, these data showed that patients with initial CR were more likely to respond than those with previous PR (85% vs. 67%, P = 0.037). There were no difference between the three initial treatment groups regarding the efficiency (CR or CR + PR) of second RT. Toxicity was low and only gastrointestinal.

CONCLUSIONS

Single-fraction RT consisting of 4 Gy was effective and little toxic treatment that could be administered after previous single-fraction RT.

A randomized trial of three single-dose radiation therapy regimens in the treatment of metastatic bone pain

PURPOSE

To investigate efficacy of three single dose radiation therapy (RT) regimens in the treatment of painful bone metastasis.

MATERIAL AND METHODS

Patient self-assessment by using pain chart enabled evaluation of response to treatment that consisted of either one of the three single fractions of 4 Gy (group I; n=109), 6 Gy (group II; n=108), or 8 Gy (group III; n=110).

RESULTS

Patients in groups II and III had higher complete response rate than those in group I, but not significantly, and with no difference between group II and III. However, both patients in group II (73%) and group III (78%) had significantly higher overall response rates when compared to those observed in group I (59%) (I vs II, p=0.025; I vs III, p=0.0019), and with no difference between groups II and III (p=0.39). Patients in group III had shortest time to the occurrence of any pain relief which was significantly better than those observed in group I (Welch's t-test, p=0.012), with no difference between group I and II and group II and III, respectively. There was no difference between the three treatment groups in duration of response and retreatment rate. No effect of histology or metastatic site treated was found. No pathological fractures or spinal cord compressions were observed during the 8 weeks post-RT.

CONCLUSION

Results of this study seem to confirm that 8 Gy could be considered as probably "lowest" optimal single fraction RT in the treatment of painful bone metastasis, although single fraction RT of 4 Gy should not be easily discarded due to its applicability in specific cases. Since single fraction RT of 6 Gy achieved results not different from that obtained with 8 Gy, further studies are warranted in order to get more informations about "lowest" optimal single fraction RT in the treatment of painful bone metastasis.

Fractionated half-body irradiation for pain palliation in widely metastatic cancers: comparison with single dose

PURPOSE

To explore fractionated half-body irradiation (HBI) for pain palliation and determine if it is more efficient and effective than single dose HBI.

METHODS AND MATERIALS

During the last 13 years, 75 out of 115 HBIs (64%) at the University of Maryland Medical Center were given for palliation of various widely metastatic cancers (28% prostate, 25% breast, 12% lung). The HBI fields were 28% upper, 25% mid, and 47% lower; three patients had both upper and lower HBI. An initial performance status (PS) 3&4 with a life expectancy < 3 months was found in 50% of patients. The HBI techniques used on consecutive patients were: single dose (SD) in 54% with escalating doses of 4-10 Gy; split-course (SC) in 12% with two 4 Gy single doses separated by 2 weeks; and daily fractionated (DF) in 34% with five fractions of 3 Gy each. There were 68 of 75 HBI (91%) given for pain control purposes.

RESULTS

The percent total (complete) pain relief was SD-73(32), SC-50(13), and DF-96(49). Time to maximum and (complete) relief was: SD 5 days each and DF HBI 7(11) days. Pain-free survival (PFS) was short but so was overall survival (OS). PFS was SD-5, SC-4.5, and DF-19 weeks. The percent of the remaining patient's life spent pain free without retreatment (NPR) was SD-38, SC-34, and DF-68. Differences in pain relief, PFS, OS, and NPR were significant and carried over primary tumor types; prostate, breast, and surprisingly GI were very responsive (90, 84, and 83%, respectively). On multivariate analysis only the PS and degree of relief were independent variables. Despite lack of premedication in DF-HBI, toxic reactions were identical to SD-HBI with premedication. No Grade 4 toxicities occurred. Grade 3 toxicities were 4%. Retreatment was 3% in SD and 13% in fractionated HBI; these differences were not significant.

CONCLUSION

HBI is still the most effective and efficient way to palliate pain from widely disseminated cancer. Fractionating HBI eliminates need for the premedication and close patient monitoring required for SD-HBI. It also allows for an increase in total dose which can produce better responses in pain relief, duration of relief, PFS, OS, and quality of life.

Skeletal metastases

This synthesis of the literature on radiotherapy for skeletal metastases is based on 171 scientific articles, including 13 randomized studies, 24 prospective studies, and 79 retrospective studies. These studies involve 13054 patients. Radiotherapy has been well documented as a method for alleviating pain, but the mechanisms underlying this effect are largely unknown. When used for pain palliation, radiotherapy achieves freedom from pain, or substantial alleviation of pain in nearly all cases, with few side effects. Half-body irradiation is effective in treating multiple metastatic sites and should be considered for use more frequently. However, this increases the requirements on equipment, dosimetry, and hospital beds. Systemic radiotherapy with radionuclides may be indicated for generalized skeletal pain. The role of radiotherapy in preventing or healing fractures is not fully evaluated. Optimum dose levels and fractionation schedules have not been established. Early radiotherapy for spinal cord compression may prevent symptoms from worsening, but the effects on existing paralysis are modest.

Irradiation and responsiveness to pain stimuli in rats

This study evaluates whether irradiation inhibits responses to pain in an animal model. We found that irradiation with doses of 10 Gy, 15 Gy and 17.5 Gy of the lumbar enlargement of the spinal cord inhibits the behavioural responses to the stimulus of the hot-plate. These doses were otherwise without effects. This data is discussed in view of the effects of irradiation of living cells, and we propose that a modification of pain signal processing is accomplished. Similar considerations apply to the human condition.

A prospective randomised trial of 4 Gy or 8 Gy single doses in the treatment of metastatic bone pain

270 patients with painful bone metastases requiring palliative radiotherapy were randomised to receive single fractions of 4 Gy or 8 Gy in a randomised trial. Pain scores and analgesic usage were recorded before treatment and at 2, 4, 8 and 12 weeks. Pain was assessed by patients on a 4 point graded scale using pain charts administered by a central trials office. Response was defined as an improved rating compared to the pretreatment value. Compliance with the pain chart was 72% at 4 weeks. At 4 weeks, the actual response rates were 69% for 8 Gy and 44% for 4 Gy (p less than 0.001), but there was no difference in complete response (no pain) rates at 4 weeks or duration of response between the two arms. It is concluded that 8 Gy gives a higher probability of pain relief than 4 Gy, but that 4 Gy can be an effective alternative in situations of reduced tolerance.