Journal of Clinical Oncology, Vol 23, No 21 (July 20), 2005: pp. 4803
© 2005 American Society of Clinical Oncology.
DOI: 10.1200/JCO.2005.01.4126
In Reply:
Tsuyoshi Hamaoka,
John E. Madewell,
Donald A. Podoloff,
Gabriel N. Hortobagyi,
Naoto T. Ueno
The University of Texas M.D. Anderson Cancer Center, Houston, TX
We appreciate the supportive comments from Gainford et al. As they noted, the most accurate assessment of bone tumor response may well require use of several measurement techniques, such as imaging, symptom assessments, and measurements of bone turnover and tumor markers. Certainly, reliable ways of assessing bone tumor response would be greatly useful for establishing the optimal duration of bisphosphonate treatment, which has yet to be determined. Although we focused on bone imaging in our review,1 we recognize that markers of bone turnover such as NTx may be powerful tools for assessing response, and we agree that measuring bone turnover markers in addition to using multiple radiographic imaging techniques may facilitate accurate assessments of bisphosphonate efficacy. Indeed, several reports2,3 have indicated that bone turnover markers show promise for assessing bone response, including results of a multicenter double-blind, randomized trial conducted by the European Organisation for Research and Treatment of Cancer.2 In that trial, urinary calcium, hydroxyproline, and NTx and serum CA 15.3 and cancer-associated serum antigen levels were measured at baseline and after 1 month and 4 months of pamidronate. Of those markers, only NTx could reliably distinguish patients whose disease would progress from those whose disease would respond to treatment or not change.1,2 We highly recommend that these findings be confirmed in prospective clinical trials involving comprehensive bone tumor assessments with a combination of bone imaging and bone turnover measurements. At The University of Texas M.D. Anderson Cancer Center (Houston, TX), we are now conducting such a trial to verify x-ray, skeletal scintigraphy, and computed tomography scanning for assessing bone tumor response. The end point of this trial is to assess the sensitivity and specificity of each imaging modality and each set of response criteria (ie, those proposed by the World Health Organization, by the International Union Against Cancer, and by us). Unfortunately, this protocol may not be useful for clarifying responses of bone metastases to bisphosphonates because the plan is to analyze response to systemic chemotherapy and hormonal therapy. However, we do believe that measurements of NTx, which have been included in the protocol, will provide some useful information. We hope that the results of this trial will lead to improvements in the assessment of treatment response in bone metastasis.
Authors' Disclosures of Potential Conflicts of Interest
The authors indicated no potential conflicts of interest.
REFERENCES
1. Hamaoka T, Madewell JE, Podoloff DA, et al: Bone imaging in metastatic breast cancer. J Clin Oncol 22:2942-2953, 2004[Abstract/Free Full Text]
2. Coleman RE: Monitoring of bone metastases. Eur J Cancer 34:252-259, 1998
3. Vinholes J, Coleman R, Lacombe D, et al: Assessment of bone response to systemic therapy in an EORTC trial: Preliminary experience with the use of collagen cross-link excretion—European Organisation for Research and Treatment of Cancer. Br J Cancer 80:221-228, 1999[CrossRef][Medline]
Related Correspondence
- Systemic Treatment of Bone Metastases From Breast Cancer: Is It All That It’s Cracked Up to Be?
Mary C Gainford, George Dranitsaris, and Mark Clemons
JCO 2005 23: 4802-4803
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