Part II: Cancer in Indigenous Africans--causes and control.

Africa has contributed substantial knowledge to the understanding of certain risk factors for cancer, such as the role of several infectious agents (eg, viruses, bacteria, and parasites), aflatoxins, and certain lifestyle factors. Although the relative importance of many lifestyle factors is becoming better understood in developed countries, more work is needed to understand the importance of these factors in different African settings. In view of the substantial genetic diversity in Africa, it would be prudent not to generalize too widely from one place to the next. We argue that risks for several exposures related to certain cancers differ from the patterns seen in developed countries. In this paper, we review the current knowledge of causes of some of the leading cancers in Africa, namely cancers of the cervix, breast, liver, prostate, stomach, bladder, and oesophagus, Kaposi's sarcoma, non-Hodgkin lymphoma, and tobacco-related cancers. There are no comprehensive cancer-control programmes in Africa and provision of radiotherapy, chemotherapy, and palliation is inadequate. Certain cost-effective interventions, such as tobacco control, provision of antiretroviral therapy, and malarial and bilharzial control, can cause substantial decreases in the burden of some of these cancers. Vaccinations against hepatitis B and oncogenic human papilloma viruses can make the biggest difference, but very few countries in Africa can afford these vaccines without substantial subsidization.

Part I: Cancer in Indigenous Africans--burden, distribution, and trends.

Cancer is an under-emphasised issue in Africa, partly because of the overwhelming burden of communicable diseases. However cancer is a common disease in Africa with 650 000 people, of a population of 965 million, diagnosed annually. Furthermore, the lifetime risk in females (between 0 and 64 years) of cancer is about 10%, which is only about 30% lower than the risk in developed countries. In females, the lifetime risk of dying from cancer in Africa is almost double the risk in developed countries. This Review is the first of two papers and focuses on the current knowledge of the distribution and trends of the most common cancers in Africa. The cancers with the highest incidence are cervical, breast, and now HIV-associated Kaposi's sarcoma. The top five cancers in males--Kaposi's sarcoma (constituting 12.9% of all cancers in males) and cancer of the liver (14.8%), prostate (9.5%), bladder (6.1%), and non-Hodgkin lymphoma (5.7%)--and in females--cancer of the cervix (constituting 23.3% of all cancers in females) and breast (19.2%), Kaposi's sarcoma (5.1%), cancer of the liver (5.0%), and non-Hodgkin lymphoma (3.7%)--are discussed in detail. The second paper will focus on the causes and control of cancer in Africa. The cancer burden in Africa is likely to increase as a result of increases in HIV-associated cancers, changes in lifestyles associated with economic development, and the increasing age of the population (despite AIDS). Although the knowledge of cancer in this region is improving, better surveillance of cancer incidence, mortality, and prevalence of risk factors is urgently needed to monitor the development of the cancer epidemic, formulate appropriate cancer-control strategies, and assess the outcomes of these strategies.

Lung cancer management in limited resource settings: guidelines for appropriate good care.

Lung cancer is a major cause of cancer death worldwide and is becoming an increasing problem in developing countries. It is important that, in countries where health care resources are limited, these resources are used most effectively and cost-effectively. The authors, with the support of the International Atomic Energy Agency, drew on existing evidence-based clinical guidelines, published systematic reviews and meta-analyses, as well as recent research publications, to summarise the current evidence and to make broad recommendations on the non-surgical treatment of patients with lung cancer. Tables were constructed which summarise the different treatment options for specific groups of patients, the increase in resource use for and the likely additional clinical benefit from each option. These tables can be used to assess the cost-effectiveness and appropriateness of different interventions in a particular health care system and to develop local clinical guidelines.

Audits of oncology units - an effective and pragmatic approach.

BACKGROUND: Audits of oncology units are part of all quality-assurance programmes. However, they do not always come across as pragmatic and helpful to staff. OBJECTIVE: To report on the results of an online survey on the usefulness and impact of an audit process for oncology units. METHODS: Staff in oncology units who were part of the audit process completed the audit self-assessment form for the unit. This was followed by a visit to each unit by an assessor, and then subsequent personal contact, usually via telephone. The audit self-assessment document listed quality-assurance measures or items in the physical and functional areas of the oncology unit. There were a total of 153 items included in the audit. The online survey took place in October 2016. The invitation to participate was sent to 59 oncology units at which staff members had completed the audit process. RESULTS: The online survey was completed by 54 (41%) of the 132 potential respondents. The online survey found that the audit was very or extremely useful in maintaining personal professional standards in 89% of responses. The audit process and feedback was rated as very or extremely satisfactory in 80% and 81%, respectively. The self-assessment audit document was scored by survey respondents as very or extremely practical in 63% of responses. The feedback on the audit was that it was very or extremely helpful in formulating improvement plans in oncology units in 82% of responses. Major and minor changes that occurred as a result of the audit process were reported as 8% and 88%, respectively. CONCLUSION: The survey findings show that the audit process and its self- assessment document meet the aims of being helpful and pragmatic.

Lung toxicity following chest irradiation in patients with lung cancer.

Classical radiation pneumonitis has been described after single dose whole lung irradiation in experimental animals where above a threshold dose of irradiation, there is a sigmoid dose response curve with increasing morbidity and mortality. After clinical fractionated irradiation, however, acute radiation pneumonitis consisting of cough shortness of breath and patchy radiological changes, occurs in <10% of patients, has dyspnoea out of proportion to the volume of lung irradiated and usually resolves completely without long-term effects. There is increasing evidence that this represents a bilateral lymphocytic alveolitis or hypersensitivity pneumonitis and has been termed sporadic pneumonitis. Late radiation toxicity results in pulmonary fibrosis. This is a consequence of repair, which is initiated by tissue injury within the radiation portal. It follows release of chemotactic factors for fibroblasts including transforming growth factor-beta, fibronectin and platelet derived growth factor. Radiation fibrosis is the clinically more significant syndrome for patients. It may result in progressive dyspnoea and mortality in patients. The most predictable change in laboratory lung function tests is a decrease in transfer factor due to damage at the capillary-alveolar level. It also results in decreased lung compliance, which will affect the total lung capacity and the forced vital capacity. The forced expiratory volume in 1 s is less affected, although this seems to depend on the volume of lung irradiated. There is also a decrease in perfusion in the irradiated lung. Radiation fibrosis seems to depend, amongst other factors, on the volume of lung, which is irradiated above a threshold of 20-30 Gy. The morbidity of radiation fibrosis may therefore be minimized by the use of dose volume histogram to minimize the volume of normal lung irradiated in patients at high risk, e.g., patients with who present with poor lung function. The importance of the baseline perfusion in the irradiated areas continues to be studied.

Hypofractionated irradiation for non-small cell lung cancer.

Large radiation fractions are an effective way of killing tumour cells but have generally been avoided in curative treatment of patients because of concerns of a disproportionate increase in late normal tissue toxicity. Radiobiological modelling of the effect of radiation on lung tumours and late-reacting normal tissues, which are more sensitive to large radiation fractions, has been undertaken. The biological effect of radiation on tumours is increased as the overall treatment time is shortened but this is not true for late-reacting normal tissue. Sample data are shown in which the relative increases in radiation effect on the tumour and late-reacting normal tissues are similar after hypofractionation. A favourable therapeutic ratio can be achieved because the bulk of normal tissue will receive a lower dose of radiation at a lower dose per fraction than the tumour, especially with current techniques where the volume of normal tissue irradiated can be sharply reduced. The clinical evidence confirms that lung toxicity is volume-dependent. It is the small Stage I and II tumours which are most likely to benefit from hypofractionated regimens, as the volumes to be treated are smaller and they have a lower incidence of distant metastases. Patients with Stage III tumours with favourable prognostic factors are nowadays treated with combined chemotherapy and radiotherapy and so for this group more conservative hypofractionation regimens are being explored. However, more advanced tumours may be treated with hypofractionation to lower total doses to achieve palliation and a modest degree of survival benefit.

Asbestos and mesothelioma in South Africa.

Asbestos has been used by man since 4000 before the Christian era (BCE) in many different parts of the world and for a wide range of functions. Blue asbestos (crocidolite) was first discovered in South Africa in 1805 and within a few years was being mined there extensively. Mining reached its peak in 1977 with >380,000 tons being exported and 20,000 miners employed in the industry. South Africa also has large deposits of white asbestos (chrysotile) and brown asbestos (amosite) both of which have been mined extensively. At the turn of the 20th century, it was noted that those working with asbestos suffered lung disease and in 1960, the link between asbestosis and mesothelioma was established in the Kimberley area of South Africa. Further studies in the 1970s and 1980s showed an alarming incidence of mesothelioma based on pathology reports. The majority of the reported mesothelioma cases result from exposure to asbestos in its many uses in secondary industry although incidence of the condition among miners is also significant. A high proportion of mesothelioma in patients in South Africa is attributed to environmental origin with a high incidence of women and children affected.

Pulmonary complications of radiation therapy.

There have been important developments in understanding the difference in pathogenesis and clinical significance between acute or sporadic pneumonitis and late radiation fibrosis. Corticosteroid therapy and other forms of therapy are useful in the treatment of acute pneumonitis. Late radiation fibrosis is refractory to treatment; therefore, minimizing the likelihood of developing it is particularly important. Baseline lung assessments are appropriate in patients who are clinically at risk. A new development is the use of the DVH to compare radiation treatment plans to minimize the volume of normal lung irradiated in patients who are at risk. It is hoped that the study of mechanisms that lead to the development of radiation fibrosis will point the way to possible future therapies. Patients who are included in studies of novel irradiation treatments for lung cancer need, in particular, to be monitored for late radiation lung toxicity.

Vandetanib plus pemetrexed for the second-line treatment of advanced non-small-cell lung cancer: a randomized, double-blind phase III trial.

PURPOSE: Vandetanib is a once-daily oral inhibitor of vascular endothelial growth factor receptor and epidermal growth factor receptor signaling. This randomized, placebo-controlled phase III study assessed the efficacy of vandetanib plus pemetrexed as second-line therapy in advanced non-small-cell lung cancer. PATIENTS AND METHODS: Patients (N = 534) were randomly assigned to receive vandetanib 100 mg/d plus pemetrexed 500 mg/m(2) every 21 days (n = 256) or placebo plus pemetrexed (n = 278). Progression-free survival (PFS) was the primary end point; overall survival, objective response rate, disease control rate, time to deterioration of symptoms, and safety were secondary assessments. RESULTS: There was no significant difference in PFS between treatment arms (hazard ratio [HR], 0.86; 97.58% CI, 0.69 to 1.06; P = .108). Overall survival was also not significantly different (HR, 0.86; 97.54% CI, 0.65 to 1.13; P = .219). Statistically significant improvements in objective response rate (19% v 8%; P < .001) and time to deterioration of symptoms (HR, 0.71; P = .0052; median, 18.1 weeks for vandetanib and 12.1 weeks for placebo) were observed in patients receiving vandetanib. Adding vandetanib to pemetrexed increased the incidence of some adverse events, including rash, diarrhea, and hypertension, while showing a reduced incidence of nausea, vomiting, anemia, fatigue, and asthenia with no reduction in the dose intensity of pemetrexed. CONCLUSION: This study did not meet the primary end point of statistically significant PFS prolongation with vandetanib plus pemetrexed versus placebo plus pemetrexed. The vandetanib combination showed a significantly higher objective response rate and a significant delay in the time to worsening of lung cancer symptoms versus the placebo arm as well as an acceptable safety profile in this patient population.