Immediate and delayed autologous abdominal microvascular flap breast reconstruction in patients receiving adjuvant, neoadjuvant or no radiotherapy: a meta-analysis of clinical and quality-of-life outcomes

BACKGROUND

Effects of postmastectomy radiotherapy (PMRT) on autologous breast reconstruction (BRR) are controversial regarding surgical complications, cosmetic appearance and quality of life (QOL). This systematic review evaluated these outcomes after abdominal free flap reconstruction in patients undergoing postoperative adjuvant radiotherapy (PMRT), preoperative radiotherapy (neoadjuvant radiotherapy) and no radiotherapy, aiming to establish evidence-based optimal timings for radiotherapy and BRR to guide contemporary management.

METHODS

The study was registered on PROSPERO (CRD42017077945). Embase, MEDLINE, Google Scholar, CENTRAL, Science Citation Index and ClinicalTrials.gov were searched (January 2000 to August 2018). Study quality and risk of bias were assessed using GRADE and Cochrane's ROBINS-I respectively.

RESULTS

Some 12 studies were identified, involving 1756 patients (350 PMRT, 683 no radiotherapy and 723 neoadjuvant radiotherapy), with a mean follow-up of 27·1 (range 12·0-54·0) months for those having PMRT, 16·8 (1·0-50·3) months for neoadjuvant radiotherapy, and 18·3 (1·0-48·7) months for no radiotherapy. Three prospective and nine retrospective cohorts were included. There were no randomized studies. Five comparative radiotherapy studies evaluated PMRT and four assessed neoadjuvant radiotherapy. Studies were of low quality, with moderate to serious risk of bias. Severe complications were similar between the groups: PMRT versus no radiotherapy (92 versus 141 patients respectively; odds ratio (OR) 2·35, 95 per cent c.i. 0·63 to 8·81, P = 0·200); neoadjuvant radiotherapy versus no radiotherapy (180 versus 392 patients; OR 1·24, 0·76 to 2·04, P = 0·390); and combined PMRT plus neoadjuvant radiotherapy versus no radiotherapy (272 versus 453 patients; OR 1·38, 0·83 to 2·32, P = 0·220). QOL and cosmetic studies used inconsistent methodologies.

CONCLUSION

Evidence is conflicting and study quality was poor, limiting recommendations for the timing of autologous BRR and radiotherapy. The impact of PMRT and neoadjuvant radiotherapy appeared to be similar.

Abstract P4-15-02: Impact of radiotherapy and endocrine therapy on further events: Final multivariate analysis of a prospective, national cohort study of screen detected ductal carcinoma in situ (DCIS) of the breast

Key words: DCIS, radiotherapy, endocrine therapy, survival, surgical margins

Background:

The benefits and risks of breast screening remain controversial, with particular concern that ductal carcinoma in situ (DCIS) may be over-diagnosed and over-treated. There is little prospective data on treatment or outcomes for screen detected DCIS.

Methods:

A prospective cohort of non-invasive lesions diagnosed through the United Kingdom National Health Service Breast Screening Programme (NHSBSP) (1 April 2003 to 31 March 2012) was linked to national databases and case note review to analyse patterns of care, recurrence and mortality.

Results:

Screen-detected DCIS in 9938 women was analysed, 33% (9938/30041) of women with a final diagnosis of non-invasive breast neoplasia diagnosed through the NHSBSP over the same time.

The patients (mean age was 60 years: range 46-87 years) were treated by breast conservation surgery (BCS; 7007; 70.5%) or mastectomy (2931). At 64 months median follow up, 697 (6.8%) had further DCIS or invasive breast cancer after BCS (7.8%) or mastectomy (4.5%) (p<0.001) and 228 women (2.3%) developed contralateral malignancy.

Breast radiotherapy (RT) after BCS (4363/7007; 62%) was associated with a 3.1% absolute reduction in any ipsilateral DCIS or invasive cancer (No RT: 7.2% vs RT: 4.1% (p<0.001) and a 1.9% absolute reduction for ipsilateral invasive breast recurrence (No RT: 3.8% vs RT: 1.9% (p<0.001), independent of excision margin width or size of DCIS. Women who did not receive RT after BCS had more ipsilateral events (p=0.008) when the radial excision margin was <2mm. RT was rarely used after mastectomy for DCIS (33 women). Adjuvant endocrine therapy (prescribed for 1208/9938; 12.2%) was associated with a reduction in any ipsilateral recurrence, independent of whether women did (HR 0.57: 95% CI 0.41 - 0.80) or did not (HR 0.68: 95% CI 0.51 - 0.91) receive RT after BCS.

Among 321 (3.2%) women who died, 46 deaths (0.5%; 14.3% of all deaths) were attributed to invasive breast cancer. Death from breast cancer was uncommon and outnumbered 5:1 by death due to other causes. RT after BCS was associated with a non-significant 0.2% absolute reduction in breast cancer mortality. However, women who developed invasive breast cancer had a worse survival than those with further DCIS (p<0.001).

Conclusions:

Recurrent DCIS or invasive cancer is uncommon following screen detected DCIS treated by surgery and adjuvant therapy. Both RT and endocrine therapy following surgery were associated with a significant reduction in further DCIS and invasive disease, but not breast cancer mortality, within 5 years of diagnosis. This study quantifies the benefits of radiotherapy and endocrine therapy to inform decision making in the management of screen detected DCIS.

Citation Format: Thompson AM, Clements K, Cheung S, Pinder SE, Lawrence G, Sawyer E, Kearins O, Ball GR, Tomlinson I, Hanby AM, Thomas J, Maxwell AJ, Wallis MG, Dodwell DJ. Impact of radiotherapy and endocrine therapy on further events: Final multivariate analysis of a prospective, national cohort study of screen detected ductal carcinoma in situ (DCIS) of the breast [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-15-02.

Abstract P4-15-04: A longitudinal cohort study to identify risk factors for the development of invasive cancer in unresected DCIS

Background: The variable natural history of ductal carcinoma in situ (DCIS) remains poorly understood. Randomized trials of active surveillance versus guideline concordant care are currently underway: the Comparison of Operative to Monitoring and Endocrine Therapy (COMET) trial in the US, LOw Risk dcIS (LORIS) trial in the UK and Low Risk Dcis (LORD) in Europe. Given this context, we examined the outcomes of a contemporary group of women with DCIS who did not undergo initial surgical resection.

Methods: A longitudinal cohort of women diagnosed with DCIS on needle biopsy who did not undergo initial surgical excision for ≥1 year were identified through the Cancer Registry with case note and death certificate review for subsequent outcomes.

Results: Eighty-nine eligible women with DCIS alone diagnosed on needle biopsy (most with 14-gauge core needle biopsy) between 1998 and 2010 were identified. The mean age at diagnosis was 72 years (range 44-94 years) with mean follow-up (diagnosis to death, invasive disease or last review) of 62 months (range 12-180 months). Twenty-nine women (33%) developed histologically proven invasive breast cancer, 28 at the site of the initial DCIS biopsy, after a mean interval of 54 months (range 12-144 months): 14/29 (48%) women originally had high grade DCIS, 10/31 (32%) intermediate grade and 3/17 (18%) low grade DCIS (initial grade not known in 12). Time to detect a diagnosis of invasive breast cancer was associated with initial grade of DCIS (p=0.0016, log-rank test): after mean intervals of 41 months (high grade), 69 months (intermediate grade) and 78 months (low grade) respectively. Younger age was associated with development of invasive disease (p<0.003, Mann-Whitney U-Test). High grade (grade 3) invasive breast cancer exclusively occurred in women with a prior diagnosis of high grade DCIS. Invasion was more frequent in lesions with calcification as the predominant feature than those without (23/50 v. 5/25; p<0.05, Fisher exact test). Forty-four women were prescribed endocrine therapy, use of which was associated with a lower rate of invasive breast cancer (p<0.05). Ultimately 18 women underwent surgery, 17 for invasive cancer. The mean interval from DCIS diagnosis to death was 76 months for those who developed invasive cancer; 48/89 women died, 12 had a certified cause of death as breast cancer.

Conclusion: High grade DCIS, mammographic microcalcification and lack of endocrine therapy were associated with progression to invasion. The findings suggest surgical excision of high grade DCIS should continue but provides support that women with DCIS features which include low grade should be considered for the COMET, LORIS or LORD active surveillance trials.

Citation Format: Maxwell AJ, Clements K, Hilton B, Dodwell DJ, Evans A, Olive K, Pinder SE, Thomas J, Matthew WG, Thompson AM. A longitudinal cohort study to identify risk factors for the development of invasive cancer in unresected DCIS [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-15-04.

Dose-finding study of weekly docetaxel, epirubicin and capecitabine, as first-line treatment in advanced breast cancer

BACKGROUND

Combinations of anthracycline, taxane and fluoropyrimidine are highly active in advanced breast cancer (ABC). In a phase II study of epirubicin 50 mg/m(2), docetaxel 75 mg/m(2), and infusional 5-FU 200 mg/m(2)/day, we found dose-limiting neutropenia and frequent central venous catheter complications. An alternative approach has been tested using weekly fractionation of docetaxel, and oral capecitabine.

METHODS

Initially, six women with ABC were treated with epirubicin 60 mg/m(2) day 1, docetaxel 25 mg/m(2) days 1,8,15, and capecitabine 1,000 mg/m(2) twice daily days 1-14, every 21 days. Six further patients received the above with capecitabine escalated to 1,500 mg/m(2)

RESULTS

Four DLTs occurred in six patients at the second dose level (febrile neutropenia in 2). There were frequent dose delays/reductions, and fatigue, nausea/vomiting, and diarrhoea were common. Overall, six of ten assessable patients achieved a partial response.

CONCLUSIONS

An active regimen, but significant haematological toxicity precluded dose further escalation.

Aromatase inhibitors and musculoskeletal symptoms

AIMS

Recent evidence shows aromatase inhibitors (AIs) to be of benefit over tamoxifen in the adjuvant setting. It is also apparent that musculoskeletal symptoms associated with AIs may be a significant problem in the clinical setting. The aim of this article is to review the data on AIs with respect to musculoskeletal symptoms in the adjuvant setting.

MATERIAL AND METHODS

A review on the literature relating to AIs in the adjuvant setting and musculoskeletal symptoms.

RESULTS

Results of phase III trials show lower incidence of musculoskeletal symptoms than reported in the clinical setting.

DISCUSSION

AIs offer a significant advantage over tamoxifen. More research is required to ascertain the cause and to define the spectrum of musculoskeletal symptoms reported in women taking AIs. Decision of appropriate treatment should be made jointly between clinician and patient after full discussion of the risks and benefits.

A randomised study of whole-breast vs tumour-bed irradiation after local excision and axillary dissection for early breast cancer

AIMS

Whole-breast radiotherapy (WBRT) after conservative surgery for early breast cancer is a routine standard of care. Despite this, a number of uncertainties in management still exist. Over recent years, a number of new technologies have allowed the development of partial-breast irradiation, with the intention of improving the risk-benefit relationship of routine breast radiotherapy. We report the results of a trial comparing partial- with WBRT, with prolonged follow-up.

MATERIALS AND METHODS

Between 1986 and 1990, 174 women were randomised to receive conventional whole-breast radiotherapy (WBRT) (40 Gy in 15 fractions), with a tumour-bed boost or partial-breast irradiation by a variety of techniques. Recruitment was problematic, and the trial closed prematurely well before meeting its recruitment target.

RESULTS

A trend was observed towards higher local recurrence and a higher locoregional recurrence rate after irradiation of the tumour bed alone. Distant recurrence and survival were the same.

CONCLUSIONS

Conclusions are limited in view of the failure to complete accrual of the target of 400 participants, and in the context of the techniques of partial-breast radiotherapy used during this study, which would not compare with those in current use. Tumour-bed irradiation alone cannot currently be recommended as routine treatment outside the context of clinical trial.

FriÐfinnsson, Hreinn

The bisphosphonate pamidronate (3 amino-1, 1-hydroxypropylidene bisphosphonate (APD), Ciba-Geigy) is a powerful inhibitor of osteoclast function and has been shown to significantly reduce osteolysis associated with bone metastases in breast cancer. Until recently, however, only an intravenous preparation has been readily available. We have evaluated the toxicity and effect on urinary calcium excretion of an enteric-coated oral preparation of pamidronate in a phase I/II trial in patients with bone metastases from breast cancer. Sixteen women with progressive disease and evidence of active bone resorption with an elevated calcium excretion (fasting urine calcium/creatinine ratio greater than 0.4 (mmol mmol-1) on two occasions prior to treatment) were studied. Four were given 150 mg daily; four 300 mg daily; four 450 mg daily and four 600 mg daily. Urinary calcium/creatinine (Ca2+/Cr) ratios were measured on all patients after an overnight fast. In patients on 150 mg daily the mean ratio fell from 0.65 (range 0.57-0.72) before treatment to 0.13 (0.02-0.19) after three weeks treatment. Mean values at entry for patients on 300, 450 and 600 mg were 1.18 (0.72-2.1), 0.76 (0.42-1.5) and 0.63 (0.52-0.82) respectively and after treatment these fell to 0.11 (0.05-0.18), 0.37 (0.14-0.68) and 0.17 (0.06-0.25). There were no significant differences in efficacy between treatment groups. Oral, enteric-coated disodium pamidronate is non-toxic and effectively reduces calcium excretion, raised in association with metastatic bone disease at doses of 150 mg or above. At the doses used to date it is as effective as weekly treatments with 30 mg of the intravenous preparation. Further studies are required in order to determine its value for preventing complications of bone disease and possibly as an adjuvant to surgery for breast cancer.

Morbidity of tamoxifen–perceptions of patients and healthcare professionals

There is little published data comparing patients' and doctors' perceptions of tamoxifen-related morbidity and toxicity, in particular in terms of side-effects which are not medically serious but which disrupt quality of life. We undertook a questionnaire-based study of 210 randomly selected, disease-free pre- and post-menopausal breast cancer patients to assess perceived morbidity whilst taking tamoxifen. We also questioned 143 healthcare professionals, including nurses, GPs and oncologists, on their opinions of tamoxifen-related side-effects. This study suggests that patients experience significant morbidity while taking adjuvant tamoxifen but will tolerate this for the sake of anticipated benefits. Healthcare professionals particularly hospital-based doctors and specialist nurses tend to overestimate the prevalence and severity of tamoxifen-associated symptoms.

Optimum anthracycline-based chemotherapy for early breast cancer

Adjuvant chemotherapy improves the overall survival of women treated after surgery for early breast cancer. Several trials have suggested that anthracycline-containing regimens are more effective than those that do not contain anthracyclines. A modest overall benefit has also been confirmed by the Early Breast Cancer Trialists' Collaborative Group overview. Newer agents, such as the taxanes, are now being tested in the adjuvant setting in randomised trials. The control group of such studies should receive the optimum standard treatment. There are several anthracycline-based regimens in common use, varying in terms of the type of anthracycline used, the dose, and drug scheduling. We review the available evidence and consider whether the optimum anthracycline-containing chemotherapy schedule has now been identified.

Activity of pemetrexed (ALIMTA, multitargeted antifolate, LY231514) in metastatic breast cancer patients previously treated with an anthracycline and a taxane: an interim analysis

As many breast cancer patients receive adjuvant chemotherapy using anthracyclines or anthracenediones and taxanes, more therapeutic options are needed for subsequent lines of therapy. Pemetrexed (ALIMTA, multitargeted antifolate, LY231514) is a novel antifolate that inhibits several enzymes in the de novo pathways of pyrimidine and purine biosynthesis. This paper reports on a subset analysis of a phase II clinical trial of pemetrexed in heavily pretreated metastatic breast cancer (MBC) patients. Patients were required to have received prior first-line anthracycline therapy for metastatic disease. Prior adjuvant chemotherapy and prior taxanes were allowed. A substantial subset of the study population (31 of 72 patients, 43%) had also received a taxane in the metastatic setting. All patients were treated with pemetrexed, 600 mg/m2 by intravenous infusion, once every 21 days. In the study subset, 23 of 31 (74%) patients were anthracyclines failures (progression > 30 days following treatment), and eight (26%) patients were anthracyclines refractory (progression during or < or = 30 days of treatment). The median age was 55 years (range, 30-75 years) and the median World Health Organization performance status was 0. Metastases were present in the liver (61%), lung (29%), bone (6%), and soft tissue (19%). The overall response rate for this subset was 26%, with one complete response, seven partial responses, and 13 (42%) patients with stable disease. The median duration of response was 5.4 months and median survival was 12.8 months. Pemetrexed was well tolerated by patients in the study. This post hoc analysis suggests promising activity in MBC patients previously treated with both anthracyclines and taxanes. An ongoing trial is prospectively evaluating activity in this same population.

A randomized, open, parallel-group trial to compare the endocrine effects of oral anastrozole (Arimidex) with intramuscular formestane in postmenopausal women with advanced breast cancer

BACKGROUND

This study provides a direct randomized comparison of a new-generation, non-steroidal aromatase inhibitor, anastrozole (Arimidex), with a steroidal aromatase inhibitor (formestane) with respect to oestrogen (oestradiol, oestrone, and oestrone sulphate) suppression and tolerability.

PATIENTS AND METHODS

Sixty postmenopausal women with advanced breast cancer were randomized to receive either anastrozole 1 mg once daily orally (n = 29), or formestane 250 mg once every two weeks by intramuscular injection (n = 31). Treatment was continued until progression of disease or withdrawal from the study. The primary endpoints of this study were oestradiol suppression and tolerability. The secondary endpoints included oestrone and oestrone sulphate suppression. All laboratory analyses were conducted 'blind' of the randomized drug treatment.

RESULTS

Anastrozole produced a greater and more consistent suppression of oestradiol levels compared with formestane. Based on two- and four-week measurements, the mean fall from baseline (pre-dose) in oestradiol level was 79% and 58% in the anastrozole and formestane groups, respectively (P = 0.0001). After four weeks of treatment, oestrone and oestrone sulphate levels were also suppressed to a greater extent by anastrozole compared with formestane (oestrone: 85% versus 67%, respectively, P = 0.0043; oestrone sulphate: 92% versus 67%, respectively, P = 0.0007). No statistical differences were seen between the two drugs in the incidence of adverse events.

CONCLUSIONS

Anastrozole provides a more consistent and significantly more effective suppression of oestradiol compared with formestane. Similar results were observed for oestrone and oestrone sulphate. The clinical significance of these differences in total oestrogen suppression remains to be established.

A randomised comparison of oestrogen suppression with anastrozole and formestane in postmenopausal patients with advanced breast cancer

The relative efficacy and tolerability of the aromatase inhibitors anastrozole (Arimidex) and formestane are assessed in a direct comparative trial in postmenopausal women with advanced breast cancer. Final results are available and reported here only for oestradiol suppression. Patients were randomised to receive either oral anastrozole, 1 mg once daily, or formestane, 250 mg every 2 weeks intramuscularly. In the anastrozole group, mean serum oestradiol levels fell from 32.1 pmol/l at baseline to 6.5 pmol/l at week 1, and similar levels of suppression were maintained over the next 3 weeks. In the formestane group, mean serum oestradiol levels fell from 31.0 pmol/l at baseline to 9.5 pmol/l at the week 1 assessment. In this group, serum oestradiol levels tended to rise by the 2- and 4-week measurements, i.e. immediately before the next injection was due. Based on the 2- and 4-week measurements, the mean falls in oestradiol levels were 79 and 58% in the anastrozole and formestane groups, respectively (p = 0.0001). More effective and consistent suppression of oestradiol was achieved with anastrozole at the therapeutic dose of 1 mg once daily, orally, than with formestane at the standard dose of 250 mg every 2 weeks, intramuscularly.

Survival from cancer: local control and radiotherapy

Adjuvant radiotherapy is considered to be highly effective in maintaining local control but is widely perceived to confer no survival advantage in the management of solid tumours. However, recent adjuvant radiotherapy studies are beginning to show survival improvements in parallel with improvements in loco-regional disease control.

An audit of the management of malignant hypercalcaemia

A protocol was designed to help junior doctors to manage patients with malignant hypercalcaemia (MH). Seventy-five patients received 30 mg, 60 mg or 90 mg doses of pamidronate, depending on their initial serum calcium level. Fifty-four (72%) patients achieved normocalcaemia (NC) within 5 days after a single infusion of pamidronate. A further ten (13%) patients reached NC after a second dose, and 11 (15%) remained hypercalcaemic until death. NC was maintained for a median duration of 24 days. Patients received, on average, 30 mg less pamidronate than that given in the manufacturer's dosing schedule. The protocol was considered effective, economical and practical in the routine management of MH.

Skin telangiectasia: the influence of radiation dose delivery parameters in the conservative management of early breast cancer

A retrospective analysis was performed to study the occurrence of skin telangiectasia in patients with conservatively treated early breast cancer who were given postoperative radiotherapy that included an electron boost. Patients managed in two different centres were treated with identical techniques but different schedules of radiotherapy. Electron boost site telangiectasia was less common in those patients treated at the centre that employed higher doses, longer schedules and lower fraction sizes of both photons and electrons. These results require prospective confirmation but they suggest that schedules of radiotherapy employing lower fraction sizes, longer treatment times and higher total doses may minimize the incidence of skin telangiectasia.

Etoposide-related myocardial infarction

The occurrence of a myocardial infarction is reported after chemotherapy containing etoposide, in a man with no risk factors for coronary heart disease. Possible causal mechanisms are discussed.

Malignant schwannoma following treatment for Hodgkin's disease

Two cases of malignant schwannoma are reported 13 and 15 years following combined modality treatment for Hodgkin's disease. Both patients survived for only 15 months. The aetiology of this rare condition is discussed.

High dose, dose-intensive chemotherapy with doxorubicin and cyclophosphamide for the treatment of advanced breast cancer

Eighteen patients with advanced breast cancer were commenced on treatment with high dose doxorubicin (100 mg m-2) or doxorubicin (100 mg m-2) and cyclophosphamide (500 mg m-2) at 2 weekly intervals. Three cycles of treatment were planned. rG-CSF was given subcutaneously for 10 days, starting 24 h after each cycle of chemotherapy. Sixteen out of 18 patients responded (89%) of whom six (33%) achieved a complete remission. Twelve (67%) completed the three planned cycles, four (22%) received two cycles and two (11%) received one cycle only. The median time to progression was 5 1/2 months and the median survival was 18 1/2 months. Neutropenia occurred after 89% of courses and 65% of courses were accompanied by a significant (WHO grade III or IV) infection. The duration of neutropenia was short (mean 5.4 days) and mean time to absolute neutrophil count recovery (ANC > 1,000 x 10(6) litre) from the start of treatment was 11 days. Moderate to severe epithelial toxicity (WHO grade 3 or 4) accompanied 43% of courses and was dose limiting.

CONCLUSION

High dose, dose intensive chemotherapy has an excellent initial therapeutic effect in advanced breast cancer but does not prolong duration of remission or overall survival beyond that of standard treatment. Although subcutaneous rG-CSF curtailed the expected duration of neutropenia substantially, the overall incidence of neutropenia and of infections requiring intravenous antibiotics was high. Furthermore, almost half of the courses were complicated by moderate to severe oral mucositis and/or mild to moderate palmar and plantar inflammation. The lack of survival benefit and excess toxicity seriously limits the wider application of this regime. It should not be used in place of standard dose palliative chemotherapy for metastatic breast cancer.

Assessment of palliative chemotherapy: a step beyond response

In summary, tumour response is a useful index of cytotoxic activity, but is of limited value in the assessment of benefit to the patient following treatment with cytotoxic drugs. Survival is a similarly inappropriate endpoint to assess the clinical benefits of palliative cytotoxic therapy. The widespread introduction of QL assessment as a primary outcome measure in cancer therapy will enhance our understanding of the value of a wide range of established cancer treatments, not only that of palliative chemotherapy, but also surgery and radiotherapy.

Response after withdrawal of tamoxifen and progestogens in advanced breast cancer

Tumor response after withdrawal of endocrine therapy for advanced breast cancer with estrogens and androgens is well described. There have been few reports of withdrawal responses (WRs) after cessation of treatment with the newer antiestrogens and progestogens. We assessed WR in women after cessation of adjuvant therapy at first relapse, and after progression on first, second or third line endocrine therapy for advanced disease. One of seven patients (14%) responded after cessation of tamoxifen adjuvant therapy at relapse. Sixty-five of 72 patients were evaluable for WR after cessation of tamoxifen as first line therapy for advanced disease. There were five partial responses (8%) and 14 (22%) 'no change' with a median duration of WR of 10 months (range 3-40 months). WR were seen mainly in soft tissue disease but there were two responses in lung and two in bone. Four of 21 (19%) patients had a WR after cessation of norethisterone acetate (3) and tamoxifen (1), all used as second line therapy. WR are therefore demonstrable after cessation of tamoxifen and norethisterone acetate with durations of response similar to those found with additive therapy. Assessment of WR may represent a way of prolonging the overall response duration in patients with relatively indolent metastatic breast cancer, particularly in soft tissues.

Infusion rate and pharmacokinetics of intravenous pamidronate in the treatment of tumour-induced hypercalcaemia

We report the results of two consecutive randomized studies in the treatment of malignant hypercalcaemia with intravenous pamidronate. Overall normocalcaemia was achieved in greater than 90% of patients and a single infusion of 60 mg pamidronate given over 2 hours was as effective in restoring normocalcaemia as infusions given over 4, 8 or 24 hours. Similarly duration of normocalcemia after treatment with pamidronate and the control of the symptoms of hypercalcaemia were independent of infusion rate. Study of the pharmacokinetics of pamidronate in the treatment of hypercalcaemia show this drug to have a very high clearance due to calcified tissue retention and renal excretion. The initial half life of the drug in plasma is very short and most of the drug is cleared before distribution equilibrium is achieved. Short infusions of pamidronate are as safe and effective as infusions given over a longer time and are therefore to be preferred because of their greater convenience.

The clearance and bioavailability of pamidronate in patients with breast cancer and bone metastases

The pharmacokinetics and bioavailability of pamidronate were assessed in patients with breast cancer, 6 subjects received the drug intravenously and 7 orally. The initial plasma half-life of pamidronate was short (42 +/- 27 min) and the apparent total plasma clearance was high (471 +/- 298 ml/min). The renal clearance (74 +/- 34 ml/min) was similar to the creatinine clearance (66 +/- 19 ml/min). Most of the renal elimination occurred during and immediately post a 4 h infusion of the drug (23.2 +/- 7.9% in 24 h). The non-renal clearance was ascribed to uptake by bone and deep tissue compartments. Little additional drug appeared in the urine after 24 h. The mean bioavailability was estimated using a parallel study design to be 0.3% for a 300 mg oral dose.

Parathyroid hormone-related protein(50-69) and response to pamidronate therapy for tumour-induced hypercalcaemia

A region-specific radioimmunoassay has been employed to measure levels of immunoreactive parathyroid hormone-related protein(50-69) (iPTHrP(50-69)) in patients with tumour-induced hypercalcaemia (TIH). This assay is based on an antiserum raised against synthetic human PTHrP(50-69). The assay showed no cross-reactivity with human or bovine parathyroid hormone(1-84). The effect of a single dose (60 mg) of pamidronate was studied in 25 consecutive patients with TIH. All were rehydrated prior to treatment. All but 2 patients (8%) became normocalcaemic after treatment; both of these had very high levels of iPTHrP(50-69). Time to achieve normocalcaemia, as an index of relative resistance to pamidronate, correlated positively with pretreatment level of iPTHrP(50-69). Absence of radiological evidence of bone metastases also predicted relative resistance to pamidronate. In this study, iPTHrP(50-69)-induced osteoclastic bone resorption was a more important mechanism in the causation of TIH than PTHrP-induced renal reabsorption of calcium as assessed by the renal thresholds for calcium and phosphate.

Reduction in calcium excretion in women with breast cancer and bone metastases using the oral bisphosphonate pamidronate

The bisphosphonate pamidronate (3 amino-1, 1-hydroxypropylidene bisphosphonate (APD), Ciba-Geigy) is a powerful inhibitor of osteoclast function and has been shown to significantly reduce osteolysis associated with bone metastases in breast cancer. Until recently, however, only an intravenous preparation has been readily available. We have evaluated the toxicity and effect on urinary calcium excretion of an enteric-coated oral preparation of pamidronate in a phase I/II trial in patients with bone metastases from breast cancer. Sixteen women with progressive disease and evidence of active bone resorption with an elevated calcium excretion (fasting urine calcium/creatinine ratio greater than 0.4 (mmol mmol-1) on two occasions prior to treatment) were studied. Four were given 150 mg daily; four 300 mg daily; four 450 mg daily and four 600 mg daily. Urinary calcium/creatinine (Ca2+/Cr) ratios were measured on all patients after an overnight fast. In patients on 150 mg daily the mean ratio fell from 0.65 (range 0.57-0.72) before treatment to 0.13 (0.02-0.19) after three weeks treatment. Mean values at entry for patients on 300, 450 and 600 mg were 1.18 (0.72-2.1), 0.76 (0.42-1.5) and 0.63 (0.52-0.82) respectively and after treatment these fell to 0.11 (0.05-0.18), 0.37 (0.14-0.68) and 0.17 (0.06-0.25). There were no significant differences in efficacy between treatment groups. Oral, enteric-coated disodium pamidronate is non-toxic and effectively reduces calcium excretion, raised in association with metastatic bone disease at doses of 150 mg or above. At the doses used to date it is as effective as weekly treatments with 30 mg of the intravenous preparation. Further studies are required in order to determine its value for preventing complications of bone disease and possibly as an adjuvant to surgery for breast cancer.