The Mre11-Rad50-Nbs1 complex mediates the robust recruitment of Polo to DNA lesions during mitosis in Drosophila

The DNA damage sensor Mre11-Rad50-Nbs1 complex and Polo kinase are recruited to DNA lesions during mitosis. However, their mechanism of recruitment is elusive. Here, using live-cell imaging combined with micro-irradiation of single chromosomes, we analyze the dynamics of Polo and Mre11 at DNA lesions during mitosis in Drosophila These two proteins display distinct kinetics. Whereas Polo kinetics at double-strand breaks (DSBs) are Cdk1-driven, Mre11 promptly but briefly associates with DSBs regardless of the phase of mitosis and re-associates with DSBs in the proceeding interphase. Mechanistically, Polo kinase activity is required for its own recruitment and that of the mitotic proteins BubR1 and Bub3 to DSBs. Moreover, depletion of Rad50 severely impaired Polo kinetics at mitotic DSBs. Conversely, ectopic tethering of Mre11 to chromatin was sufficient to recruit Polo. Our study highlights a novel pathway that links the DSB sensor Mre11-Rad50-Nbs1 complex and Polo kinase to initiate a prompt, decisive response to the presence of DNA damage during mitosis.

Myosin efflux promotes cell elongation to coordinate chromosome segregation with cell cleavage

Chromatid segregation must be coordinated with cytokinesis to preserve genomic stability. Here we report that cells clear trailing chromatids from the cleavage site by undergoing two phases of cell elongation. The first phase relies on the assembly of a wide contractile ring. The second phase requires the activity of a pool of myosin that flows from the ring and enriches the nascent daughter cell cortices. This myosin efflux is a novel feature of cytokinesis and its duration is coupled to nuclear envelope reassembly and the nuclear sequestration of the Rho-GEF Pebble. Trailing chromatids induce a delay in nuclear envelope reassembly concomitant with prolonged cortical myosin activity, thus providing forces for the second elongation. We propose that the modulation of cortical myosin dynamics is part of the cellular response triggered by a “chromatid separation checkpoint” that delays nuclear envelope reassembly and, consequently, Pebble nuclear sequestration when trailing chromatids are present at the midzone.

Chromatid segregation must be coordinated with cytokinesis to preserve genomic stability. Here the authors show that cells clear trailing chromatids from the cleavage site in a two-step cell elongation and demonstrate the role of myosin efflux in the second phase.

Bub3-BubR1-dependent sequestration of Cdc20Fizzy at DNA breaks facilitates the correct segregation of broken chromosomes

BubR1 depends on its association with Bub3 to localize on DNA breaks during mitosis, where it sequesters Cdc20^Fizzy and induces the inhibition of the APC/C locally, promoting the faithful segregation of broken chromatids.

The presence of DNA double-strand breaks during mitosis is particularly challenging for the cell, as it produces broken chromosomes lacking a centromere. This situation can cause genomic instability resulting from improper segregation of the broken fragments into daughter cells. We recently uncovered a process by which broken chromosomes are faithfully transmitted via the BubR1-dependent tethering of the two broken chromosome ends. However, the mechanisms underlying BubR1 recruitment and function on broken chromosomes were largely unknown. We show that BubR1 requires interaction with Bub3 to localize on the broken chromosome fragments and to mediate their proper segregation. We also find that Cdc20, a cofactor of the E3 ubiquitin ligase anaphase-promoting complex/cyclosome (APC/C), accumulates on DNA breaks in a BubR1 KEN box–dependent manner. A biosensor for APC/C activity demonstrates a BubR1-dependent local inhibition of APC/C around the segregating broken chromosome. We therefore propose that the Bub3–BubR1 complex on broken DNA inhibits the APC/C locally via the sequestration of Cdc20, thus promoting proper transmission of broken chromosomes.

Mammographically detected ductal carcinoma in situ of the breast treated with breast-conserving surgery and definitive breast irradiation: long-term outcome and prognostic significance of patient age and margin status

PURPOSE

This study was performed to determine the long-term outcome for women with mammographically detected ductal carcinoma in situ (DCIS; intraductal carcinoma) of the breast treated with breast-conserving surgery followed by definitive breast irradiation.

METHODS AND MATERIALS

An analysis was performed of 422 mammographically detected intraductal breast carcinomas in 418 women from 11 institutions in North America and Europe. All patients were treated with breast-conserving surgery followed by definitive breast irradiation. The median follow-up time was 9.4 years (mean, 9.4 years; range, 0.1-19.8 years).

RESULTS

The 15-year overall survival rate was 92%, and the 15-year cause-specific survival rate was 98%. The 15-year rate of freedom from distant metastases was 94%. There were 48 local failures in the treated breast, and the 15-year rate of any local failure was 16%. The median time to local failure was 5.0 years (mean, 5.7 years; range, 1.0-15.2 years). Patient age at the time of treatment and final pathology margin status from the primary tumor excision were both significantly associated with local failure. The 10-year rate of local failure was 31% for patient age < or = 39 years, 13% for age 40-49 years, 8% for age 50-59 years, and 6% for age > or = 60 years (p = 0.0001). The 10-year rate of local failure was 24% when the margins of resection were positive, 9% when the margins of resection were negative, 7% when the margins of resection were close, and 12% when the margins of resection were unknown (p = 0.030). Patient age < or = 39 years and positive margins of resection were both independently associated with an increased risk of local failure (p = 0.0006 and p = 0.023, respectively) in the multivariable Cox regression model.

CONCLUSIONS

The 15-year results from the present study demonstrated high rates of overall survival, cause-specific survival, and freedom from distant metastases following the treatment of mammographically detected ductal carcinoma in situ of the breast using breast-conserving surgery and definitive breast irradiation. Younger age and positive margins of resection were both independently associated with an increased risk of local failure. The 15-year results in the present study serve as an important benchmark for comparison with other treatment modalities. These results support the use of breast-conserving surgery and definitive breast irradiation for the treatment of appropriately selected patients with mammographically detected ductal carcinoma in situ of the breast.

Salvage treatment for local recurrence after breast-conserving surgery and radiation as initial treatment for mammographically detected ductal carcinoma in situ of the breast

BACKGROUND

The purpose of the current study is to evaluate the outcome of salvage treatment for local recurrence after breast-conserving surgery and radiation as initial treatment for mammographically detected ductal carcinoma in situ (DCIS; intraductal carcinoma) of the breast.

METHODS

An analysis was performed of 42 patients with local only first failure (n = 41) or local-regional only first failure (n = 1) after breast-conserving surgery and radiation treatment had been given for DCIS of the breast. Surgical treatment at the time of local recurrence included mastectomy (n = 37; 88%) or excision (n = 5; 12%). Adjuvant systemic therapy at the time of local recurrence was chemotherapy (n = 3; 7%), tamoxifen (n = 8; 19%), both (n = 1; 2%), none (n = 29; 69%), or unknown (n = 1; 2%). The median interval from the time of initial treatment to local recurrence was 4.8 years (range = 1.0-15.2 yrs). The median follow-up after salvage treatment was 4.5 years (range = 0.2-12.8 yrs).

RESULTS

At the time of the local recurrence, 22 patients (52%) had invasive ductal carcinoma, 18 patients (43%) had DCIS, 1 patient (2%) had invasive lobular carcinoma, and 1 patient (2%) had angiosarcoma. After salvage treatment, the rate of overall survival and the rate of cause specific survival for all 42 patients were 92% at both 5- and 8-years after treatment. The rate of freedom from distant metastases was 89% at 5 and 8 years. Favorable prognostic factors after salvage treatment were DCIS as the histology of the local recurrence and mammography only as the method of detection of the local recurrence.

CONCLUSIONS

The results of salvage treatment in the current study demonstrated that local recurrences were salvaged with high rates of survival and freedom from distant metastases. These results support the use of breast-conserving surgery and radiation for initial management of DCIS of the breast.

Combined chemoradiotherapy with daily low-dose cisplatin in locally advanced inoperable non-small cell lung cancer

Sixty-one consecutive patients with locally advanced inoperable non-small-cell lung cancer were treated with chemoradiation with 60 Gy and concomitant daily low-dose cisplatin (6 mg/m(2)) in a single uninterrupted course. Toxicity was mild, 80% of patients were treated as outpatients. The median survival of 70 weeks compares favorably to the literature.

[Malignant course of pigmented villonodular synovitis of the flexor tendon sheath of the small finger--case report and review of the literature]

The case of a 55-year-old patient is described, presenting the clinical sign of a chronic infection of the tendon sheath. Upon incision a mass of brown synovial tumor was found. The X-ray showed a circumscript bone erosion. MRI demonstrated tumor involvement of all flexor tendons up to the forearm. Under radiation the tumor initially was diminished. Half a year later, pulmonary metastases were found. The destruction of the whole skeleton of the hand led to a forearm amputation. Later, a metastasis was found in the tongue. The patient died with the clinical signs of pulmonary insufficiency. Autopsy showed diffuse pulmonary metastases. This case is discussed together with other rare cases of malignant pigmented villonodular synovialitis arising from joints and tendon sheaths.

Effect of radiotherapy on brain glucose metabolism in patients operated on for low grade astrocytoma

OBJECTIVE

To assess the effect of postoperative radiotherapy on brain glucose metabolism (CMRGlu) of operated patients with low grade astrocytomas.

METHODS

PET and 18F-fluorodeoxyglucose was used to measure absolute CMRGlu in patients with fibrillary astrocytoma (WHO II) of the frontal lobe, who did (n=7) or did not (n=12) receive radiotherapy subsequent to first debulking tumour resection. In addition, statistical parametric mapping (SPM95) was applied to assess the pattern of relative CMRGlu associated with the frontal tumour. Data were compared with 12 healthy controls.

RESULTS

A global reduction of absolute CMRGlu was found when either patients with or without radiotherapy were compared with controls (ROI analysis). Brain areas of relative CMRGlu reduction were found in the brain ipsilateral and contralateral to the tumour, comparing both patient groups with controls by SPM ("tumour diaschisis effect"). Superimposed, absolute CMRGlu in the contralateral frontal, parietal, occipital cortex as well as in the white matter was on average 17% lower in patients receiving radiotherapy than in patients who did not.

CONCLUSIONS

The data discriminate a tumour effect from a radiotherapy effect, and support the view of adverse effects of radiotherapy on brain not directly involved by tumour.

Concurrent platinum-based chemotherapy and hyperfractionated radiotherapy with late intensification in advanced head and neck cancer

PURPOSE

To determine whether a course of hyperfractionated radiation therapy concomitant with escalated radiosensitizing platinum compounds can be administered with acceptable morbidity and achieve a high rate of loco-regional control for Stage III and IV head and neck cancer and whether the patients can be tumor free at the primary site after initial therapy and cured by the additional chemoradiation without radical resection of the primary tumor.

METHODS AND MATERIALS

Patients with Stage III/IV head and neck cancer were treated in this multicenter Phase II Study with 1.8 Gy fraction radiotherapy for 2 weeks, with escalation to 1.2 Gy b.i.d. hyperfractionation to 46.8 Gy. Concomitant continuous infusion cisplantinum (CDDP) 20 mg per meter square on day 1 to 4 and 22 to 25 was given. Reassessment by biopsy of primary and nodes was done. Patients with a complete response continued with hyperfractionated radiotherapy to 75.6 Gy with simultaneous carboplatinum (Carbo), 25 mg per meter square b.i.d. for 12 consecutive treatment days. Patients with residual disease at 46.8 Gy required curative surgery. Seventy-four patients were treated at the three institutions; 20 were Stage III and 54 were Stage IV. All patients had daily mouth care, nutritional, and psychosocial support.

RESULTS

This regime was well tolerated. Eighty-five percent of toxicities were Grade 1 or 2 and there was only one Grade 4 hematologic toxicity. Late toxicities included xerostomia in 25 patients, dysphasia in 18, and mild speech impediment in 11. Biopsies of primary site were done after the first course of treatment in 59 patients. Neck dissections were performed in 35 patients. Forty-four of 59 (75%) primary sites and 16 of 35 (46%) lymph nodes had pathologically complete response (CR). Of the 74 patients, only 12 required surgical resection of the primary site. Thirty-five of the 50 node positive patients had neck dissections, 16 of these were CRs at surgery. At 4 years (median follow-up of 26 months), disease-specific survival is 63%. The actuarial survival for all patients is 51%. Patients with pathological CR after initial treatment have disease specific survival of 73% at 4 years vs. 48% of patients with partial response (PR) only.

CONCLUSION

This study, developed on the basis of radiobiological and cell kinetic precepts, produced results that compare favorably with other reports of management of patients with advanced head and neck cancer. In comparison with our previous study, these results are comparable, not impressively better. The associated morbidity was somewhat worse.

[Breast preserving therapy of breast carcinoma: analysis of over 1,300 patients treated in the Basel region]

From 1977 to 1994 a total of 1329 breast cancer patients have been treated with breast conserving surgery in the region of Basel. This analysis is based on 832 patients treated from 1977 to 1990 according to a prospective treatment protocol, which was adjusted only once (1985). In comparison with the most known international publications this analysis represents one of the greatest homogeneous series of breast conserving treatment. We observe an overall 5-year survival of 91% and a 10-year survival rate of 77%. 94% of the women remain locally recurrence free at 5 years and 86% at 10 years respectively. At 5 years, freedom of local recurrence totals to 97% in patients without (pN0) and to 89% in patients with tumor involvement of the axillary lymph nodes (pN+) (p = 0.00008), as well as to 96% for pT1 and 91% for pT2-tumors (p = 0.08328). In our analysis the R0-resection significantly influences local recurrence free survival.

[Which way ahead? Carcinoma of the exocrine pancreas, the gallbladder and the bile ducts--nonsurgical therapy in the locally advanced and in the metastasized stage]

Carcinomas of the pancreas, gallbladder and bile ducts in inoperable stages can be treated with chemotherapy, radiotherapy and a combination of both modalities. Therapy is always palliative. In the past 20 years treatment results have not improved. Patients treated should be entered in controlled clinical studies with new substances randomized versus less toxic 5-FU or optimum supportive care. Pain and jaundice can be relieved by radiotherapy, bypass surgery and stent insertion. The choice of an option should be made according to patient characteristics and risk factors, as well as the possibilities and experience of the treating center.

Adverse effect of transurethral resection on disease-free survival in locally advanced prostatic cancer treated with irradiation

PURPOSE

The purpose of this study was to analyze the impact of transurethral resection of the prostate on prognosis in patients with localized prostate cancer who received definitive external beam radiotherapy.

METHODS AND MATERIALS

Out of the 431 patients treated diagnosis was established by needle biopsy in 198 and by transurethral resection of the prostate in 233 cases. Disease-free survival and relative survival as a function of transurethral resection of the prostate and needle biopsy were calculated for all stages and within each tumor stage and grade.

RESULTS

An adverse effect of transurethral resection of the prostate on disease-free survival was observed only in patients with T3 T4 tumors of intermediate and poor differentiation (p < 0.05). The incidence of local recurrence and distant metastases as well as the distribution of pretreatment prostate specific antigen-levels was not significantly different between the transurethral resection of the prostate and needle biopsy groups.

CONCLUSION

We conclude that transurethral resection of the prostate has an adverse effect on disease-free survival in a selected group of patients and discuss the implications of this finding.

[Orbitocranial plasmacytoma: a case report]

A female patient aged 79 years suffered from a unilateral, slowly progressive and painless exophthalmus. The investigations lead to the diagnosis of a voluminous plasma cell tumor involving the fossa infratemporalis, a part of the lateral orbit, as well as the middle and anterior cerebral fossae. This rare case is described and placed in its clinico-pathological context.

The role of laminectomy in the combined treatment of metastatic spinal cord compression

A retrospective analysis of clinical data concerning 140 patients with spinal cord compression is presented. Treatment consisted of a surgical decompressive laminectomy followed by radiation therapy in 127 cases. Primary radiation therapy supported by steroids was applied in only 26 cases. A dose of 30-40 Gy in 15-20 fractions was delivered to all patients. Treatment outcome was analyzed by comparing motor function (categories: no deficit, mild deficit ambulatory, paraparetic not ambulatory, paraplegic), sphincter function, and pain relief before and after treatment in both modalities. Following laminectomy and radiation therapy, 82% of paraparetic patients regained their ability to walk, sphincter function improved in 68%, pain relief was achieved in 88%. Following radiation therapy alone, 64% of paraparetic patients became ambulatory, 33% showed a normalization of sphincter function, and 72% became pain free. Our results indicate that laminectomy should play a major role in the treatment of patients with metastatic spinal cord compression. The decision as to the treatment of choice has to be made individually for each patient taking into consideration his general condition, life expectancy, and origin of the primary.

Prostatic specific antigen as an indicator of response to radiotherapy in prostate cancer

The effectiveness of prostatic specific antigen (PSA) as an indicator of response to radiotherapy and as a predictor of tumor recurrence was studied. Serum PSA values of 71 patients with regionally confined prostate cancer, who were irradiated with aim at cure, were measured before irradiation, at the end of radiotherapy, 6 weeks later, and in 6-month intervals thereafter. The patients were followed for 12-30 months with a median follow-up time of 18 months. PSA was determined using a polyclonal radioimmunoassay, a level of 12.2 ng/ml was considered the normal limit. Sixty-five per cent (46/71) of the patients had elevated PSA levels before starting irradiation. Six weeks after completion of therapy, 60% (28/46) of the primarily elevated PSA levels fell below 12.2 ng/ml. Six months later, 74% (34/46) of the PSA levels returned to normal. Twelve months after completion of radiotherapy, only two additional patients showed a normalization of PSA levels raising the rate to 78% (36/46). Out of the remaining ten patients with persisting elevated PSA values at 12 months, five were screened for metastases and found to be positive. We conclude that PSA values which fail to normalize 6 months after the resumption of treatment carry a high risk of recurrence. PSA values were found to correlate well with estimated clinical tumor stage. Comparison of PSA and prostatic acid phosphatase (PAP) levels indicate PSA to be the more sensitive tumor marker, allowing earlier detection of tumor at diagnosis and during follow-up.

[Orchidectomy only for stage I testicular teratoma?]

In the past few years the therapeutic options for non-seminomatous germ-cell tumors of the testis have evolved rapidly. Until recently it was usual practice with patients in clinical stage I to perform lymphadenectomy or retroperitoneal radiotherapy after orchidectomy. However, for 60-80% of these patients this therapy was not necessary, since they were already cured by orchidectomy alone. With the improvement of clinical staging and the success of modern chemotherapy, it seems to be possible to follow up stage I patients clinically. The various aspects which justify this "wait-and-see" strategy are discussed. Further, the question is discussed whether all patients in clinical stage I may be treated in this way, or whether specific groups at severe risk of metastatic disease at the time of orchidectomy should be excluded.

Quality control of radiotherapy in acute lymphocytic leukemia protocol treatment: experience with 610 cases

Quality assurance programs are necessary in multi-institutional cooperative group clinical trials to ensure that possible inter-institutional differences in selection, treatment and evaluation of patients will not erode the statistical assessment of these clinical trials. The Radiotherapy Committee of the Cancer and Leukemia Group B examined the evaluability and appropriateness of treatment of patients entered into two protocols for childhood acute lymphocytic leukemia, 7411 prior to and 7611 after the development of a quality assurance review program. Of the 348 patients entered into 7411, 37% were evaluable and 26% were appropriately treated in 1974 when the protocol opened. This rose to 53 and 35% in the last year of the study. On the other hand, in 7611 with an ongoing quality assurance program, the evaluability rate initially was 63% and rose to 73% and the appropriateness rate rose from 37 to 61%. This change in performance which was statistically significant at the P = 0.001 level is attributed to the impact of the Quality Assurance Review Center correspondence. Improvement in performance occurred almost entirely in the principal centers and not in satellite institutions. This difference in performance was statistically significant at the P = 0.05 level, indicating that adherence to protocol requirements increases with increased participation in studies.