Predictors of the Predominance of NonIndex Pain After Palliative Radiation Therapy for Painful Tumors

Comparison of pain-relieving effects by number of irradiations, through propensity score matching and the international consensus endpoint

Background

Palliative radiotherapy for bone metastases utilizes various dose fractionation schedules. The pain-relieving effects of a single fraction (SF) and multiple fractions (MF) are largely debated due to the difficulty in matching patients' backgrounds and in assessing the effectiveness of pain relief. This study aimed to compare the pain-relieving effects of SF and MF palliative radiotherapy for bone metastases using propensity score matching and the international consensus endpoint (ICE).

Materials and methods

Our study included 195 patients irradiated for bone metastasis. The primary endpoint was the pain-relieving effects used by ICE. In addition, the evaluation was performed by using responder (complete response/partial response) and non-responder (pain progression/indeterminate response) categorization. The secondary endpoints were the discharge or transfer rate at one month after irradiation and postirradiation pathological fracture rate. Propensity score matching was used to adjust patient's characteristics and reduce selection bias.

Results

After adapting propensity score matching, the total number of patients was 74. There was no significant difference in the pain-relieving effects between SF and MF (p = 0.184). There were no significant differences in them between SF and MF when using responder and non-responder categorization (p = 0.163). Furthermore, there were no differences in the discharge or transfer rates (p = 0.693) and pathological fracture rates (p = 1.00).

Conclusions

The combination of propensity score matching and ICE revealed no significant difference in the pain-relieving effects between SF and MF for bone metastases, thus, SF has no significant disadvantage compared to MF in pain-relieving effects.

Influence of pain duration on pain outcomes following palliative radiotherapy for painful tumors: the sooner the irradiation, the better?

PURPOSE

The influence of pre-radiotherapy pain duration on post-treatment outcomes was assessed.

METHODS

Patients that received palliative radiotherapy were analyzed in a prospective observational study investigating curative and palliative radiotherapy. Brief Pain Inventory data were acquired at baseline and 1, 2, and 3 months after commencing irradiation. The pain response in terms of the index pain (i.e., pain caused by the irradiated tumors) was assessed using the International Consensus Endpoint. Patients were diagnosed with predominance of other pain (POP) if non-index pain of malignant or unknown origin was present and showed a higher pain score than the index pain. Competing risk analyses were performed in which deaths without the pain endpoints were considered as competing events.

RESULTS

Of 229 patients analyzed, 123 (54%) experienced a pain response and 43 (19%) experienced POP. Multivariable analyses using the Fine-Gray model revealed that patients with shorter pain duration (< 1 month) had higher cumulative incidence of pain response (subdistribution hazard ratio, 2.43; 95% confidence interval [CI], 1.35-4.38) and POP (subdistribution hazard ratio, 4.22; 95% CI, 1.30-13.70) compared with patients with longer pain duration (≥ 4 months). For patients with a pain duration of less than 1 month, cumulative incidence of pain response was estimated to be 69% (95% CI, 53-85%) and cumulative incidence of POP was estimated to be 15% (95% CI, 3-28%) at 1‑month follow-up.

CONCLUSION

Commencing palliative radiotherapy earlier may improve the probability of patients achieving a pain response, although POP may be more frequent.

Introducing Computed Tomography Simulation-Free and Electronic Patient-Reported Outcomes-Monitored Palliative Radiation Therapy into Routine Care: Clinical Outcomes and Implementation Experience

Purpose

Our purpose was to report outcomes of a novel palliative radiation therapy protocol that omits computed tomography simulation and prospectively collects electronic patient-reported outcomes (ePROs).

Methods and Materials

Patients receiving extracranial, nonstereotactic, linear accelerator-based palliative radiation therapy who met inclusion criteria (no mask-based immobilization and a diagnostic computed tomography within 4 weeks) were eligible. Global pain was scored with the 11-point numerical pain rating scale (NPRS). Patients were coded as having osseous or soft tissue metastases and no/mild versus severe baseline pain (NPRS ≥ 5). Pain response at 4 weeks was measured according to the international consensus (no analgesia adjustment). Transition to ePRO questionnaires was completed in 3 phases. Initially, pain assessments were collected on paper for 11 months, then pilot ePROs for 1 month and then, after adjustments, revised ePROs from 1 year onwards. ePRO feasibility criteria were established with reference to the paper-based process and published evidence.

Results

Between May 2018 and November 2019, 542 consecutive patients were screened, of whom 163 were eligible (30%), and 160 patients were successfully treated. The proportion of patients eligible for the study improved from approximately 20% to 50% by study end. Routine care pain monitoring via ePROs was feasible. One hundred twenty-seven patients had a baseline NPRS recording. Ninety-five patients had osseous (61% severe pain) and 32 had soft tissue (25% severe pain) metastases. Eighty-four patients (66%) were assessable for pain response at 4 weeks. In the 41 patients with severe osseous pain, overall and complete pain response was 78% and 22%, respectively.

Conclusions

By study completion, 50% of patients receiving palliative extracranial radiation therapy avoided simulation, streamlining the treatment process and maximizing patient convenience. Pain response for patients with severe pain from osseous lesions was equivalent to published evidence.

Index and Nonindex Pain Endpoints in Radiation Therapy for Painful Tumors: A Secondary Analysis of a Prospective Observational Study

Purpose

Improving pain interference in daily activities, rather than mere pain reduction, is a desirable endpoint for palliative radiation therapy. The association between pain response and pain interference has been studied almost exclusively in patients with painful bone metastases (PBMs), whereas nonindex pain has scarcely been explored in palliative radiation therapy. We investigated whether index and nonindex pain endpoints are associated with pain interference changes in patients with both PBMs and painful non-bone-metastasis tumors (PNTs).

Methods and Materials

Brief pain inventory data collected at baseline and at 2 months post-treatment were used to calculate differences in pain interference scores. Pain response in terms of the index pain was assessed using the international consensus endpoint. Patients were diagnosed with predominance of other pain (POP) if nonindex pain of malignant or unknown origin was present and had a greater pain score than the index pain.

Results

Of 302 patients, 127 (42%) had PBMs and 175 (58%) had PNTs. The median pain interference score, which is based on the mean of the 7 subscale items, decreased to a greater extent among responders than among nonresponders (PBM group: –3.43 vs –0.57 [P = .005]; PNT group: –2.43 vs –0.29 [P < .001]). Moreover, patients without POP experienced a greater reduction in their median pain interference score than did those with POP (PBM group: –2.71 vs +0.43 [P = .004]; PNT group: –2.00 vs +1.57 [P = .007]). The Jonckheere-Terpstra test showed a significant trend across 4 pain response categories in patients with PBMs and those with PNTs (P < .001 for both).

Conclusions

The index and nonindex pain endpoints were positively and negatively associated with improvement in pain interference, respectively. There was no apparent difference between patients with PBMs and PNTs in terms of the associations of these endpoints with pain interference.

Inconsistencies in assessment of pain endpoints in radiotherapy for painful tumors: Analysis of original articles in the Green and Red Journals

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The frequency of use of the ICT has risen in research for PBMs.

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The frequency of the ICT use has been considerably limited for PNTs.

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None of the journal articles had investigated non-index pain.

Background and purpose

Consistent assessment of the pain response is essential for adequately comparing treatment efficacy between studies. We studied the assessment of pain endpoints in radiotherapy for painful bone metastases (PBMs) and painful non-bone-metastasis tumors (PNTs).

Material and methods

We performed a literature search in the Green (Radiotherapy and Oncology) and Red (International Journal of Radiation Oncology * Biology * Physics) Journals for full-length original articles published between 2009 and 2018. We only included articles that assessed palliation of tumor-related pain after radiotherapy. The data obtained included the definitions of pain response and assessment of non-index pain (pain other than that related to the irradiated tumors).

Results

Among the 1812 articles identified using the journals’ search function, 60 were included in the analysis. Thirty percent of the PBM articles and approximately half of the PNT articles did not report on analgesic use. Among the prospective studies, 68% of the articles on PBMs and 10% of the articles on PNTs used the International Consensus Endpoint. The PBM articles published in 2014–2018 utilized the International Consensus Endpoint more frequently than those published in 2009–2013 (p = 0.049). No articles reported information on non-index pain.

Conclusions

After the initial publication of the International Consensus Endpoint, the frequency of its use appears to have risen in PBM research; however, its use in PNT studies has been considerably limited. The International Consensus Endpoint should be consistently utilized in future studies on radiotherapy for painful tumors. Since none of the journal articles had investigated non-index pain, this issue may also needs to be addressed.

Pain Response Rates After Conventional Radiation Therapy for Bone Metastases in Prospective Nonrandomized Studies: A Systematic Review

PURPOSE

This study aimed to determine the pain response rates after conventional radiation therapy (RT) for painful bone metastases in prospective nonrandomized studies, which better reflect daily practice than randomized controlled trials.

METHODS AND MATERIALS

A literature search was conducted in PubMed and Scopus for articles published between 2002 and 2018. We only included articles in which pain response after RT was assessed using the International Consensus Endpoint initially published in 2002, or the updated version from 2012. In addition, to be included in this review, the study design was required to be prospective or based on prospectively collected data. Our primary outcomes of interest were the overall and complete response rates after conventional RT for bone metastases.

RESULTS

Of the 2863 articles identified in our database search, 12 met the inclusion criteria. Six studies excluded patients with features of complicated bone metastases. Only 2 papers reported exclusion criteria regarding analgesic use. Radiation schedules that were frequently used were 1 × 8 Gy, 5 × 4 Gy, and 10 × 3 Gy. The overall response rate in evaluable patients was 55%, and 754 of the 1379 evaluable patients experienced a complete or partial response. The complete response rate was 15% (196 of 1348 evaluable patients). In the intent-to-treat patient group, the overall response rate was 29% (754 of 2559 enrolled patients), and the complete response rate 8% (196 of 2528 enrolled patients).

CONCLUSIONS

We determined the pain response rates after conventional RT for painful bone metastases in prospective nonrandomized studies. The present review may provide benchmarks for future nonrandomized studies that investigate palliative RT for bone metastases.