The accuracy of predicting survival in individual patients with cancer

OBJECT

Estimating survival time in cancer patients is crucial for clinicians, patients, families, and payers. To provide appropriate and cost-effective care, various data sources are used to provide rational, reliable, and reproducible estimates. The accuracy of such estimates is unknown.

METHODS

The authors prospectively estimated survival in 150 consecutive cancer patients (median age 62 years) with brain metastases undergoing radiosurgery. They recorded cancer type, number of brain metastases, neurological presentation, extracranial disease status, Karnofsky Performance Scale score, Recursive Partitioning Analysis class, prior whole-brain radiotherapy, and synchronous or metachronous presentation. Finally, the authors asked 18 medical, radiation, or surgical oncologists to predict survival from the time of treatment.

RESULTS

The actual median patient survival was 10.3 months (95% CI 6.4-14). The median physician-predicted survival was 9.7 months (neurosurgeons = 11.8 months, radiation oncologists = 11.0 months, and medical oncologist = 7.2 months). For patients who died before 10 months, both neurosurgeons and radiation oncologists generally predicted survivals that were more optimistic and medical oncologists that were less so, although no group could accurately predict survivors alive at 14 months. All physicians had individual patient survival predictions that were incorrect by as much as 12-18 months, and 14 of 18 physicians had individual predictions that were in error by more than 18 months. Of the 2700 predictions, 1226 (45%) were off by more than 6 months and 488 (18%) were off by more than 12 months.

CONCLUSIONS

Although crucial, predicting the survival of cancer patients is difficult. In this study all physicians were unable to accurately predict longer-term survivors. Despite valuable clinical data and predictive scoring techniques, brain and systemic management often led to patient survivals well beyond estimated survivals.

Concurrent chemotherapy and intensity-modulated radiation therapy for anal carcinoma--clinical outcomes in a large National Cancer Institute-designated integrated cancer centre network

AIMS

To report the clinical outcomes of patients with anal carcinoma treated with intensity-modulated radiation therapy (IMRT) and concurrent chemotherapy in a large integrated academic-community cancer centre network.

MATERIALS AND METHODS

Seventy-eight patients were treated with IMRT for anal carcinoma at 13 community cancer centres. IMRT planning for all centres was carried out at one central location. Sixty-five patients (83%) were T1-T2, 64% were N0, 9% were M1; five patients were HIV positive. All but one patient received concurrent chemotherapy. The median dose to the pelvis including inguinal nodes was 45 Gy. The primary site and involved nodes were boosted to a median dose of 55.8 Gy. All acute and late toxicities were scored according to the Common Terminology Criteria for Adverse Events, version 3.0.

RESULTS

The median follow-up for the entire cohort was 16 months (range 0-72 months). Acute grade ≥3 toxicity included 27.7% gastrointestinal and 29.0% dermatological. Acute grade 4 haematological toxicity occurred in 12.9% of patients. Sixty-four (88.9%) patients experienced a complete response. The 2 year colostomy-free survival, overall survival, freedom from local failure and freedom from distant failure rates were 81.2, 86.9, 83.6 and 81.8%, respectively.

CONCLUSIONS

Early results seem to confirm that IMRT used concurrently with chemotherapy for treatment of anal carcinoma is effective and well tolerated. This complex treatment can be safely and effectively carried out in a large integrated healthcare network.

The dosimetric properties of an intraoperative radiation therapy applicator system for a Mevatron-80

An applicator system for intraoperative radiation therapy has been fabricated which does not require physical docking with the accelerator. A dosimetric study has been completed which documents the properties of this system for a variety of electron beam energies, applicator sizes, collimator settings, both primary and secondary, and source-surface distance (SSD) settings. Sensitivity of the system to common misalignment errors was also determined. Results indicate (a) applicator leakage of less than 5%, (b) beam flatness to within plus or minus 5% at the dMAX with a single primary collimator setting, (c) smooth changes in output with cone size, beam energy and SSD, and (d) negligible changes in dose distributions within alignment errors permitted by the system.