Herpes zoster in patients with carcinoma of the lung

Herpes zoster was observed in only four of 250 (1.6 percent) patients with small cell carcinoma of the lung, who were treated in a prospective, combined modality therapy trial. Induction chemotherapy in this study consisted of six courses of cyclophosphamide, doxorubicin, and vincristine (CAV), followed by intrathoracic and cranial irradiation. Those with extensive disease also received single doses of upper half-body irradiation. Patients did not receive maintenance chemotherapy (CAV2 protocol). This contrasted with our previous study (CAV1 protocol), which consisted of three courses of the same induction chemotherapy, the same intrathoracic irradiation, but with one year of oral maintenance chemotherapy. During the CAV1 regimen, we observed that herpes zoster developed in 13 of 161 (8.1 percent) patients in association with their therapy. A retrospective analysis of 6,576 patients with lung cancer revealed that herpes zoster developed in 58 (0.9 percent). This complication developed in 10 of 622 (1.6 percent) patients with small cell carcinoma of the lung, as compared to 48 of 5,954 (0.8 percent) patients with non-small cell carcinoma of the lung. The risk of development of herpes zoster in the CAV1 group was significantly greater than the historical group (p = 0.007) and was also greater than the CAV2 group (p = 0.031). However, there was no significant difference between the historical group and the CAV2 group. Attempts to explain the differences in the rate of herpes zoster in our three studies and those in the literature suggest that the duration of therapy, the type of chemotherapy used, and the improving survival rate may be important contributing factors to this complication in patients aggressively treated for small cell carcinoma of the lung. The literature and our own studies suggest that procarbazine is the most likely chemotherapeutic agent predisposing to this complication.