Do doctors know when their patients don't? A survey of doctor-patient communication in lung cancer.

OBJECTIVES: a) To determine how much patients with recently diagnosed lung cancer know about their illness and its treatment, and b) to find out if doctors know what their patients know and what they don't. PATIENTS AND METHODS: One hundred patients with recently diagnosed lung cancer, who were undergoing radiotherapy or chemotherapy, were interviewed to determine their view of their diagnosis, the extent of the cancer, the intent of treatment, and the risks and benefits of treatment. Their attending physicians' view were elicited contemporaneously, using a self-administered questionnaire. The principle outcome measure of the study was the level of agreement between the views of the patients and the doctors about the disease, the treatment, and the prognosis. Concordance between doctors' and patients' views was expressed in terms of percentage agreement, and Kappa (kappa). RESULTS: Ninety-nine percent of the patients knew that they had lung cancer. Sixty-four percent (64%) agreed with their doctor about the extent of the disease (kappa = 0.48). Most of those who disagreed underestimated the extent of their cancer. Seventy-two percent (72%) agreed with their doctor about the intent of treatment (kappa = 0.49). Thirty-six percent (36%) agreed with their doctors about their probability of cure, (kappa = 0.17): most of those who disagreed systematically overestimated it. Sixty-eight patients were receiving palliative treatment. Of these, 56% agreed with their doctor about the probability of symptomatic benefit (kappa = 0.42), but only 14% agreed with their doctor about the probability that the treatment would prolong life (kappa = 0.06). Doctors frequently failed to recognize their patients' misconceptions about the intent of treatment and the prognosis. CONCLUSION: Many patients did not understand their situation well enough to make a truly autonomous treatment decision, and their doctors often failed to recognize this.

Measuring the accuracy of prognostic judgments in oncology.

The purpose of this study was to describe the accuracy of prognostic judgments in the day-to-day practice of cancer medicine. Oncologists' initial estimates of the probability of cure of 98 cancer patients, and of the duration of survival of 39 incurable cancer patients, were compared with the observed outcome at five years. Estimates of probability of cure were well calibrated and also relatively accurate (Mean Brier Accuracy Score [AS] = 0.11 +/- 0.02 [SE]). Oncologists' ability to discriminate between curable and incurable patients compared favorably with the discrimination of prognostic judgments in acute care medicine (area under the receiver operating characteristic curve, AROC = 0.91 +/- 0.09). Estimates of the duration of survival of incurable patients were well calibrated, but individual predictions were imprecise. Discrimination between patients who would survive for three months, and those who would not, was only fair (AROC = 0.75 +/- 0.04), and discrimination between patients who would survive for one year and those who would not was very poor (AROC = 0.57 +/- 0.01). It was concluded that oncologists' estimates of probability of cure are surprisingly accurate, but estimates of the duration of survival of incurable patients are much less accurate, and subject to a "horizon effect" similar to that recognized in weather forecasting.

A comparison of delays in the treatment of cancer with radiation in Canada and the United States.

PURPOSE: Waiting lists for medical care in Canada have been used as an argument against the single-payer option for health care reform in the United States, but there have been no direct comparisons of access to care in these two health care systems. The objective of this study was to compare how long cancer patients wait for radiotherapy in Canada and the USA. METHODS AND MATERIALS: Heads of radiation oncology at all cancer centers listed by the International Union Against Cancer (UICC) in Canada and the United States were sent a questionnaire that asked how long their patients waited for radiotherapy, and how long they though it was acceptable for patients to wait, in six clinical situations. RESULTS: Ninety-two of 97 eligible centers responded (95%). Median waiting times to start of radiotherapy were as follows: carcinoma of the larynx (T2,N0,M0), 29 days in Canada, 10 days in the USA; carcinoma of the lung (Stage IIIb, squamous), 34 days in Canada, 9 days in the USA; carcinoma of the prostate (Stage B2), 40 days in Canada, 11 days in the USA; carcinoma of the breast (T2,N0,M0) referred 1 month after lumpectomy, 43 days in Canada, 10 days in the USA; carcinoma of the prostate with painful bone metastases, 17 days in Canada, 5 days in the USA; carcinoma of the prostate with spinal cord compression, < 1 day in Canada, < 1 day in the USA. The differences in waiting times between Canada and the USA were all statistically significant (p < 0.0001), except in the case of emergency treatment for cord compression. The majority of radiation oncologists in both Canada and the USA regarded the delays reported by Canadian departments as medically unacceptable. CONCLUSIONS: Patients almost everywhere in Canada wait longer for radiotherapy than they do almost anywhere in the United States.

Waiting for radiotherapy in Ontario.

PURPOSE: Waiting lists for radiotherapy are a fact of life at many Canadian cancer centers. The purpose of this study was to provide a detailed description of the magnitude of the problem in Ontario. METHODS AND MATERIALS: The interval between diagnosis and initiation of radiation treatment was calculated for all patients receiving primary radiotherapy for carcinoma of the larynx, cervix, lung, and prostate at seven Ontario cancer centers between 1982 and 1991. The interval between surgery and initiation of postoperative radiotherapy for breast cancer was also calculated over the same period. The intervals between diagnosis and referral (t1), between referral and consultation (t2), and between consultation and initiation of radiotherapy (t3), were analyzed separately to determine where delay occurred. RESULTS: Median waiting times between diagnosis and initiation of radical treatment for carcinoma of the larynx, carcinoma of the cervix, nonsmall cell lung cancer, and carcinoma of the prostate were 30.3 days, 27.2 days, 27.3 days, and 93.3 days, respectively. The exceptional interval between diagnosis and treatment of prostate cancer was due to much longer delays between diagnosis and referral. The median waiting time between diagnosis and initiation of postoperative radiotherapy for breast cancer was 61.4 days and the median time between the completion of surgery and initiation of postoperative radiotherapy was 57.8 days. There were significant intercenter variations in median waiting times, but in every situation the median waiting time in Ontario as a whole increased steadily between 1982 and 1991. Median waiting times from diagnosis to the start of curative treatment for laryngeal cancer, cervical cancer, nonsmall cell lung cancer, and prostate cancer increased by 178.7%, 105.6%, 158.3%, and 62.9%, respectively. Waiting time from completion of surgery to initiation of postoperative radiotherapy for breast cancer increased by 102.7%. Most of the increase in treatment delay was found in the interval between consultation and initiation of radiotherapy. CONCLUSIONS: The Committee on Standards of the Canadian Association of Radiation Oncologists recommends that the interval between referral and consultation should not exceed 2 weeks and that the interval between consultation and initiation of radiotherapy should also not exceed 2 weeks. The majority of patients treated in Ontario met both those standards in 1982, but by 1991 few patients received care within the prescribed intervals.

The effect of hyperthermia on transmembrane potential in Chinese hamster ovary cells in vitro.

The effect of elevated temperature on transmembrane potential was studied in Chinese hamster ovary cells in vitro using tetraphenylphosphonium cation (TPP+) and 3,3'-dipentyloxacarbocyanine [Di-O-C5(3)], two unrelated lipophilic cation probes that equilibrate across the plasma membrane according to the transmembrane potential. Uptake of TPP+ was measured using a tritium-labeled probe and the uptake of the fluorescent probe Di-O-C5(3) was measured by flow cytometry. The Nernst equation was used to calculate transmembrane potential. The absolute values obtained for transmembrane potential at 37 degrees C using the two probes were different, but qualitatively similar results were obtained using either probe in the hyperthermia studies. Transmembrane potential measured at 43 and 45 degrees C was at least 20% higher than that measured at 37 degrees C, and the difference was statistically significant (P = 0.025 and P less than 0.01, respectively). The hyperpolarization induced by exposure to 45 degrees C persisted temporarily after cells had been returned to 37 degrees C. The hyperpolarization at 37 degrees C associated with a previous exposure to hyperthermia was maximal after cells had been held at 45 degrees C for 2.0 min, and fell to normal levels after 15.0 min at 37 degrees C.